Dissertations / Theses on the topic 'Floating controlled drug delivery system'

Mestrado em Ciência e Engenharia de Materiais<br>A Drug Delivery System (DDS) may provide the precise transportation of the medical drug inside the patient’s body, directly to the pathological area or alternatively it may be also locally administrated. Once at the site of interest, the ideal DDS is expected to release the drug in a sustained manner according to the specific needs of the patient. As compared to other routes of drug administration, an appropriately designed DDS which active components are conveniently targeted should also ensure the desired in situ treatment without harmful effects of the drug over healthy tissues. The inorganic part of the human bone is mainly composed by hydroxyapatite (Ca10(PO4)6(OH)2) (HAP). Chitosan (CH), a natural polymer, is a linear glucose based polysaccharide. These two compounds are non-toxic, biodegradable and highly biocompatible and hence widely used for various biomedical applications (DDS, tissue engineering, implants, etc.). Moreover, some unique features including the amphiphilicity and good mucoadhesive properties of chitosan together with the ability of HAP to adsorb and then release different chemical species make these compounds challenging materials for DDS design. The present work addresses the combination of HAP and CH with a drug model aimed at engineering a DDS with a controlled drug release. Dexamethasone (DEX) is the drug model here selected. DEX is a corticosteroid with anti-inflammatory, antineoplastic and immunosuppressant effects, which is used for the treatment of various diseases like endocrine, dermatologic and neoplastic disorders and cancer among others. In the present research, composite granules with different ratios of HAP and CH components were produced by spray drying aqueous suspension of HAP, chitosan and DEX. To reduce polymer swelling, Glutaraldehyde (GA) was used to cross-link CH. Granules were also produced by a double spray drying technique, which so far has not been yet reported in the literature. The morphology and crystal phase composition of the produced granules were evaluated by scanning electron microscopy (SEM), N2 adsorption using the BET isotherm (BET), and X-ray diffraction (XRD). The obtained results showed that the variation of (HAP/CH) ratio affected the morphology of the granules as when that ratio increases the granules morphology changes from spherical with rough surface to a shape with concavities and smooth surface. Regarding the granules obtained by double spray drying, their morphological characteristics indicated that a core-shell structure was obtained. The drug release experiments were carried out by immersing the DEX loaded granules into phosphate buffer solution (PBS), kept at 37 °C under constant stirring. Aliquots of PBS were withdrawn after different times and their drug content evaluated by UV-Vis spectroscopy at λ= 241,5 nm. The results showed that granules with different composition could display different drug release patterns: HAP/CH granules cross-linked with GA (0,2 wt %) exhibit a more sustained drug release than granules with the same HAP/CH ratio without modification; as for double spray dried granules, a characteristic profile with a double plateau was observed, in line with a core-shell structure. Attempting to elucidate the mechanisms underlying DEX release, different mathematical models were compared with the measured release profiles. It was found that Peppas-Sahlin and Weibull equations are appropriate models for predicting the drug release from the produced granules. In conclusion, the cross-linking and morphology engineering (core-shell structure) via double spray drying allowed improving DEX release profile of HAP/CH DDSs.<br>Um sistema de libertação de fármacos (DDS) pode transportar de forma precisa o fármaco para o sítio alvo,,i.e., directamente para a zona patológica ou ser administrado localmente. Uma vez no local de interesse, o DDS deve libertar o fármaco de forma controlada, de acordo com as necessidades específicas do paciente, garantindo in situ o tratamento desejado, sem efeitos nocivos sobre os tecidos saudáveis. A parte inorgânica do osso humano é composta principalmente por hidroxiapatite (Ca10(PO4)6(OH)2) (HAP). O quitosano (CH), um polímero natural e abundante. Para além de altamente biocompatíveis estes dois compostos são biodegradáveis, podendo ser utilizados em várias aplicações biomédicas (DDS, engenharia de tecidos, implantes, etc.). Além disso, as características de anfifilicidade e as boas propriedades mucoadesivas do quitosano, somadas à capacidade da HAP para absorver diferentes espécies químicas fazem destes compostos materiais desafiantes para um projecto de DDS. O presente trabalho aborda a combinação de HAP com CH para produção de um DDS. A dexametasona (DEX), que é um corticosteróide com acção anti-inflamatória, anti-neoplásica e efeitos imunossupressores, foi o fármaco modelo seleccionado. Neste trabalho produziram-se grânulos compósitos, com diferentes proporções de HAP e CH, por atomização de suspensões aquosas de HAP, quitosano e DEX. Utilizou-se glutaraldeído (GA) para reticular o CH e procedeu-se também à dupla atomização dos grânulos, uma técnica ainda não reportada na literatura. Os ensaios de libertação do fármaco foram efectuados por imersão dos grânulos carregadas com DEX em solução de fosfato tampão mantida a 37 ° C e sob agitação constante. Alíquotas de PBS foram retiradas após diferentes períodos de tempo e a sua concentração de fármaco avaliada por UV-Vis a λ = 241,5 nm. As características morfológicas e a composição de fases cristalinas dos grânulos atomizados foram avaliadas por micróscopia eletrónica de varrimento (SEM), por adsorção de N2 usando a isotérmica de BET e por difração de raios-X (XRD). Os resultados obtidos mostraram que a variação da razão (HAP / CH) afectou a morfologia dos grânulos: quando a razão aumenta a morfologia dos grânulos evolui de esférica e rugosa para lisa e com concavidades. Por outro lado as características morfológicas dos grânulos duplamente atomizados indicam uma estrutura core-shell. No que se refere aos resultados de libertação de DEX, verificou-se que grânulos de composição diferente evidenciam perfis de libertação distintos: os grânulos reticulados com GA (0,2 %) apresentam uma curva de libertação mais lenta do que a observada para os grânulos com igual razão HAP/CH mas não modificados; quanto aos grânulos com dupla atomização, estes apresentam um padrão de libertação característico, com duplo patamar, em linha com a referida estrutura core-shell. Na tentativa de elucidar os mecanismos subjacentes à libertação de DEX, compararam-se os perfis medidos com diferentes modelos matemáticos. Verificou-se que o padrão de libertação da DEX pode ser adequadamente descrito pela equação de Peppas-Sahlin e de Weibull. Em conclusão, a reticulação e a engenharia de morfologia (estrutura core-shell) pela via da dupla atomização permitiram melhorar o perfil de libertação de DEX do DDS à base de grânulos compósitos de HAP/CH.

La presente tesis doctoral, titulada "Nanotecnología y química supramolecular en procesos de liberación controlada y reconocimiento molecular para aplicaciones biomédicas", se centra en dos temas importantes: el reconocimiento molecular y los procesos de liberación controlada. Esta tesis doctoral está estructurada en cuatro capítulos. El primer capítulo introduce el concepto de materiales híbridos orgánicos-inorgánicos funcionalizados con puertas moleculares y sus aplicaciones biomédicas como nanomateriales para dirigir y controlar la liberación controlada de fármacos. Además se introduce una breve descripción sobre sensors colorimétricos basados en la base de la quimica supramolecular, particularmente en los procesos de reconocimiento molecular. En particular, el capítulo 2 describe la preparacion de cinco nanodispositivos que responden a enzimas. Estos materiales híbridos se componen de dos unidades principales: un soporte mesoporoso basado en sílice inorgánica, capaz de encapsular moléculas orgánicas y un compuesto orgánico anclado en la superficie externa del soporte mesoporoso inorgánico que actúa como puerta molecular. Todos los sistemas propuestos utilizan puertas moleculares peptídicas que responden a temperatura o enzimas como estímulo. La segunda parte de esta tesis doctoral se centra en el diseño y desarrollo de un nuevo compuesto químico capaz de detectar monóxido de carbono in vivo. En resumen, para todos los resultados antes mencionados podemos decir que esta tesis doctoral constituye una contribución científica original al desarrollo de la química supramolecular. Sus resultados derivados de los estudios presentados dejan rutas abiertas para continuar el estudio y el desarrollo de nuevos materiales híbridos y sensors químicos más eficientes para aplicaciones biomédicas y terapeuticas.<br>This PhD thesis entitled "Nanotechnology and supramolecular chemistry in controlled release and molecular recognition processes for biomedical applications", is focused on two important subjects: molecular recognition and controlled delivery processes. This PhD thesis is structured in four chapters. The first chapter introduces the concept of organic-inorganic hybrid materials containing switchable "gate-like" ensembles and their biomedical applications as nanomaterials for targeting and control drug delivery. Furthermore, is introduced a short review about chromo-fluorogenic chemosensors based on basic principles of supramolecular chemistry, particulary in molecular recognition processes. In particular, in chapter 2 is focus on the development of enzymatic-driven nanodevices. These hybrid materials are composed of two main units: an inorganic silica based mesoporous scaffold, able to store organic molecules and an organic compound anchored on the external surface of the inorganic mesoporous support than acts as molecular gate. All the systems proposed use peptidic gates that respond to temperature or enzimatic stimulis. The second part of this PhD thesis is focused on the design and development of a new chemical compound capable of detecting carbon monoxide in vivo. In summary, for all the results above mentioned we can say that this PhD thesis constitutes an original scientific contribution to the development of supramolecular chemistry. Its results derived from the studies presented leaves open routes to continue the study and development of new hybrid materials and more efficient chemical sensors with biomedical and therapeutic applications.<br>La present tesi doctoral, titulada "Nanotecnologia i química supramolecular en processos d'alliberament controlat i reconeixement molecular per a aplicacions biomèdiques", es centra en dos temes importants de la química: el reconeixement molecular i els processos d'alliberament controlat. Aquesta tesi doctoral està estructurada en quatre capítols. El primer capítol introdueix el concepte de materials híbrids orgànics-inorgànics funcionalitzats amb portes moleculars i les seves aplicacions biomèdiques com nanomaterials per dirigir i controlar l'alliberament controlat de fàrmacs. A més s'introdueix una breu descripció sobre sensors colorimètrics fonamentats en la base de la química supramolecular, particularment en els processos de reconeixement molecular. En particular, el capítol 2 descriu la preparació de cinc nanodispositius que responen a enzims. Aquests materials híbrids es componen de dues unitats principals: un suport mesoporos basat en sílice inorgànica, capaç d'encapsular molècules orgàniques i un compost orgànic ancorat a la superfície externa del suport mesoporós inorgànic que actua com a porta molecular. La segona part d'aquesta tesi doctoral es centra en el disseny i desenvolupaent d'un nou compost químic capaç de detectar monòxid de carboni in vivo. En resum, per a tots els resultats abans mencionats podem dir que esta tesi doctoral constituïx una contribució científica original al desenvolupament de la química supramolecular. Els seus resultats derivats dels estudis presentats deixen rutes obertes per a continuar l'estudi i el desenvolupament de nous materials hibrids i sensors químics més eficients per a aplicacions biomèdiques i terapeutiques.<br>De La Torre Paredes, C. (2017). Nanotechnology and supramolecular chemistry in controlled release and molecular recognition proceses for biomedical applications" [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/94043<br>TESIS

[EN] The present PhD thesis, which is entitled "Design of new bio-gated nanodevices for advanced communication processes and targeted controlled release of therapeutic agents" is focused on the development of new functional hybrid organic-inorganic materials for applications in the field of the controlled delivery of target molecules. The first chapter of the present thesis gives an introduction to the organic-inorganic hybrid materials functionalized with "molecular gates" and its application in controlled release processes. The second chapter of this thesis is focused on the development of a new nanodevice able to deliver its cargo as a function of the glucose concentration. The nanodevice is based on mesoporous silica nanoparticles loaded with a suitable fluorophore and functionalized with propylbenzymidazole moieties on the pore outlets. The mesopores are then capped with an active cyclodextrin modified glucose oxidase enzyme (through the formation of an inclusion complex between the cyclodextrins and the propylbenzymidazole group anchored to the solid support). When glucose is added its enzymatic oxidation produced gluconic acid. This acid induced a decrease in the pH of the medium and the protonation of the benzymidazole group that might result in the inclusion complex dethreading and the subsequent cargo release. The third chapter of the thesis is focused on the development of a new redox-responsive material for the controlled delivery of cytotoxic drugs in cancer cells. The system is based on mesoporous silica nanoparticles loaded with a reporter (safranin O) and functionalized with two different sized polyethylene glycol chains in the pore outlets using a disulfide linkage. In presence of glutathione, the disulfide bonds are cleaved allowing the release of the entrapped cargo. Once confirmed the aperture protocol, the uptake of the gated nanoparticles and their ability to deliver the cargo (fluorophore or cytotoxic agent) in HeLa cells were tested. Moreover, cell viability assays were also performed. The fourth chapter of the thesis is focused on the preparation and the study of a nanodevice for the controlled delivery in senescent cells in a murine model of pulmonary fibrosis. The material is prepared using mesoporous silica nanoparticles (as an inorganic support) and galactoligosaccharide (molecular gate) moieties anchored on the external surface. In presence of senescent cells, which overexpress ß-galactosidase enzyme, the hydrolysis of the galactooligosaccharide capping molecules take place and the cargo release from the inner of the pores is produced (rhodamine B). After the in vitro studies, the ability of nanoparticles to accumulate and release their payload in tissues with abundance of senescent cells was evaluated in vivo. For that purpose, mice with induced pulmonary fibrosis, pathogenesis with associated increased alveolar senescence, were treated with the synthesized material and subsequently examined to assess its ability to accumulate and release its payload (fluorophore) in lung's damaged areas. In the fifth chapter of the thesis it has been explored the concept of cascade chemical communication using different types of nanodevices, each of them loaded with a certain messenger and externally functionalized with a gate-like entity that controls the release of the payload. When the enzyme able to hydrolyze the molecular gate that blocks the pores of the first type of nanoparticles (S1), is added to an aqueous suspension containing the three nanoparticles, the delivery of the chemical messenger 1 is produced. This messenger is able to open the second type of nanoparticles (S2) which delivers the messenger 2. Finally, the messenger 2 triggers the aperture of the third group of gated system (S3), which ultimately delivers its load (a dye) as a final response.<br>[ES] La presente tesis doctoral titulada "Diseño de nuevos nanodispositivos para procesos avanzados de comunicación y liberación controlada y dirigida de agentes terapéuticos" está centrada en el desarrollo de nuevos materiales híbridos orgánico-inorgánicos funcionales para aplicaciones en el campo de la liberación controlada de moléculas de interés. El primer capítulo de la tesis ofrece una introducción a los materiales híbridos orgánico-inorgánicos funcionalizados con "puertas moleculares" y su aplicación en procesos de liberación controlada. En el segundo capítulo de la tesis se aborda el desarrollo de un nanodispositivo capaz de responder y liberar su carga en función de la concentración de glucosa. Este nanodispositivo está basado en nanoparticulas de sílice mesoporosa funcionalizadas en su superficie externa con grupos benzimidazol y con los poros cargados con un fluoróforo. Los poros se cierran al añadir la enzima glucosa oxidasa funcionalizada con ciclodextrinas (por formación de un complejo de inclusión entre el benzimidazol y los oligosacáridos cíclicos). Al adicionar glucosa se produce su oxidación enzimática dando ácido glucónico. Este ácido induce una bajada del pH del medio con la consiguiente protonación de los benzimidazoles y la ruptura de los complejos de inclusión. Esta ruptura provoca la salida de la enzima de la superficie y la liberación del colorante atrapado en los poros. El tercer capítulo de la tesis se ha centrado en el desarrollo de un material para la liberación controlada de agentes citotóxicos en células cancerosas en respuesta a cambios en el potencial redox. De nuevo se emplean nanopartículas de sílice mesoporosa con los poros cargados con un colorante (safranina O) y la superficie externa funcionalizada con dos polietilenglicoles conteniendo enlaces disulfuro. En presencia de glutatión se produce la reducción del enlace disulfuro con la consiguiente liberación del colorante. Una vez confirmado el protocolo de apertura, se estudió la internalización y la liberación de un fluoróforo y de un agente citotóxico en el modelo celular HeLa, realizando además ensayos de viabilidad. En el cuarto capítulo de la tesis se ha preparado y ensayado un nanodispositivo para la liberación controlada en células senescentes en un modelo murino de fibrosis pulmonar. El material se prepara empleando nanopartículas de sílice mesoporosa y un galactooligosacárido anclado en la superficie externa. En presencia de células senescentes, que sobreexpresan la enzima ¿-galactosidasa, se produce la hidrólisis del oligosacárido con la consiguiente liberación de la carga atrapada en los poros del soporte (rodamina B). Tras los estudios in vitro, la capacidad del nanodispositivo de acumularse y liberar su carga en tejidos ricos en células senescentes se evaluó in vivo. Para ello, ratones con fibrosis pulmonar inducida, patología en la que se ha descrito la aparición de senescencia, se trataron con el material sintetizado y posteriormente fueron examinados para comprobar la capacidad de acumularse y liberar su carga (fluoróforo) en la zona pulmonar dañada. En el quinto capítulo se ha explorado el proceso de comunicación química en cascada empleando tres tipos de nanopartículas mesoporosas de sílice cargadas con diferentes mensajeros y funcionalizadas con tres puertas moleculares distintas. Cuando sobre una suspensión de las tres nanopartículas se añade la enzima capaz de hidrolizar la puerta molecular que bloquea los poros del primer tipo de nanopartículas (S1), se produce la liberación del mensajero 1. Este mensajero es capaz de inducir la apertura del segundo tipo de nanopartículas (S2), que a su vez liberan al medio el mensajero 2. Por último, el mensajero 2 es capaz de abrir la puerta molecular del tercer tipo de nanopartículas (S3), que liberan finalmente su carga (un colorante) como respuesta final.<br>[CAT] La present tesis doctoral titulada "Disseny de nous nanodispositius per a processos avançats de comunicació i lliberació controlada i dirigida d'agents terapèutics" està centrada en el desenvolupament de nous materials híbrids orgànic-inorgànic funcionals per a aplicacions en el camp de la lliberació controlada de molècules d'interès. El primer capítol de la tesis ofereix una introducció als materials híbrids orgànic-inorgànic funcionalitzats amb "portes moleculars" i la seua aplicació en processos de lliberació controlada. En el segon capítol de la tesis s'aborda el desenvolupament d'un nanodispositiu capaç de respondre i lliberar la seua càrrega en funció de la concentració de glucosa. Este nanodispositiu està basat en nanopartícules de sílice mesoporoses funcionalitzades a la seua superfície externa amb grups benzimidazol i amb els pors carregats amb un fluoròfor. Els pors queden bloquejats al afegir el enzim glucosa oxidasa funcionalitzada amb ciclodextrines (per formació d'un complex d'inclusió entre el benzimidazol i els oligosacàrids cíclics). Al afegir glucosa es produeix la seua oxidació enzimàtica donant lloc a àcid glucònic. Este àcid indueix una baixada del pH del medi amb la consegüent protonació dels benzimidazols i el trencament dels complexes d'inclusió. Este trencament provoca l'eixida del enzim de la superfície i la lliberació del colorant atrapat als pors. El tercer capítol de la tesis s'ha centrat en la preparació d'un material per a la lliberació controlada d'agents citotòxics en cèl¿lules canceroses en resposta a canvis en el potencia redox. De nou s'empren nanopartícules de sílice mesoporoses amb els pors carregats amb un colorant (safranina O) i la superfície externa funcionalitzada amb dos polietilenglicols (de diferent pes molecular) contenint enllaços disulfur. En presència de glutatió es produeix la reducció del enllaç disulfur amb la consegüent lliberació del colorant. Una volta confirmat el protocol d'obertura, es va estudiar la internalització i la lliberació d'un fluoròfor i d'un agent citotòxic en el model cel¿lular HeLa, realitzant ademés assajos de viabilitat. En el quart capítol de la tesis s'ha preparat i s'ha estudiat un nanodispositiu per a la lliberació controlada en cèl¿lules senescents, en un model murí de fibrosis pulmonar. El material es prepara emprant nanopartícules de sílice mesoporoses i un galactooligosacàrid anclat a la superfície externa del material. En presència de cèl¿lules senescents, que sobreexpresen el enzim ¿-galactosidasa, es produeix la hidròlisis del oligosacàrid amb el consegüent alliberament de la càrrega atrapada en els pors del suport (rodamina B). Després dels estudis in vitro, la capacitat del nanodispositiu d'acumular-se i lliberar la càrrega en teixits rics en cèl¿lules senecents es va evaluar in vivo. Amb este propòsit, ratolins amb fibrosis pulmonar induïda, patologia en la que s'ha descrit l'aparició de senescència en els teixits danyats, es van tractar amb el material sintetitzat i posteriorment van ser examinats per a comprovar la capacitat d'acumular-se i lliberar la seua càrrega (fluoròfor) en la zona dels pulmons afectada. En el quint capítol s'ha explorat el procés de comunicació química en cascada utilitzant tres tipus de nanopartícules mesoporoses de sílice carregades amb diferents missatgers i funcionalitzades amb tres portes moleculars diferents. Quan, sobre una suspensió de les tres nanopartícules, s'afegeix l'enzim capaç d'hidrolitzar la porta molecular que bloqueja els pors del primer tipus de nanopartícules (S1), es produeix la lliberació del missatger 1 des de S1. Este missatger és capaç d'induir l'obertura del segon tipus de nanopartícules (S2), les quals lliberen al medi el missatger 2. Per últim, el missatger 2 és capaç d'obrir la porta molecular del tercer tipus de nanopartícules (S3), que lliberen finalment la seua càrr<br>Giménez Morales, C. (2016). Design of new bio-gated nanodevices for advanced communication processes and targeted controlled release of therapeutic agents [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62822<br>TESIS

Pharmaceutics;<br>Ph.D.<br>The objectives of this project encompass the design and development of a drug delivery system to continuously deliver therapeutic agents from the stomach to the proximal region of the intestine. The delivery system designed would have sufficient gastric residence time together with near zero-order release kinetics. The physicochemical properties pertaining to the formulation development of the model drug (alfuzosin HCl) were evaluated. Excipients were selected based on the studies of their physicochemical properties and compatibility with the active ingredient. Gastro-retentive dosage forms have been the topic of interest in recent years as a practical approach in drug deliveries to the upper GI tract or for release prolongation and absorption. These dosage forms are particularly suitable for drugs that have local effects on the gastric mucosa in the stomach. Other candidates include drugs that are likely to be absorbed in the upper small intestine, or drugs that are unstable in basic environment of distal intestine and colon or those with low solubility at elevated pH conditions (i.e. weak bases). To develop a gastro-retentive delivery system the following steps were taken. First, to investigate the possible incompatibility issues between the model drug and excipients to be used for the delivery system. Stability and physicochemical properties of the active agent and its mixture with excipients were studied using analytical techniques such as Raman spectroscopy and Differential scanning calorimetry (DSC). No incompatibility issues were detected. Second, Kollidon SR as a relatively new release-rate controlling polymer was incorporated in the final formulation. For solid dosage form the ability of the final powder mix to flow well during manufacturing and the intrinsic characteristics that make it compressible are critical. The in-depth compaction study of Kollidon SR was assessed with the help of a compaction simulator. The flowability, swelling and erosion behavior together with release-rate retarding properties of Kollidon SR were also assessed. The final oral delivery system was based on Kollidon SR and Polyethylene Oxide (PEO) 303 as a monolithic matrix system. The noneffervescent monolithic matrix was made by direct compression. In vitro evaluation of the designed system released the active content in a near zero manner. The dosage form was bouyant in pH 2.0 acidic buffer with no floatation lag time which minimizes the possibility of early gastric emptying.

ABSTRACT In the late stage of the disease, breast cancer patients often develop bone metastases, a major cause of cancer-related death among women worldwide. The common treatment currently used clinically includes the anti-neoplastic agent paclitaxel combined with the bisphosphonate alendronate. Paclitaxel is an anti-neoplastic drug which cytotoxic effect is mainly attributed to its ability to promote the assembly of microtubules as well as prevent the depolymerisation of these microtubules. Stabilization of the microtubule networks stops mitotic functions that, in sequence, blocks cell division. Paclitaxel is approved for treatment of ovarian, breast, and non-small cell lung cancers at late stage. However, the anti-tumour drug is highly hydrophobic and consequently is poorly soluble in water. Additionally, the formulation of paclitaxel currently used clinically, known as Taxol, contains the anti-neoplastic drug dissolved in a mixture of Cremophor EL and ethanol in order to increase its solubility. Nevertheless, administration of Cremophor EL results in serious dose-limiting toxicities such as hypersensitivity responses and neuropathy. Furthermore, the chemotherapeutic agent suffers from poor selectivity towards tumours, leading to damage of normal healthy cells. As a result, much effort has been made into the development of novel formulations of paclitaxel using biocompatible and biodegradable polymeric systems. Additionally, bone metastases are of considerable concern for patients with advanced breast cancer. Patients may tackle supplemental challenges to the cancer itself as their skeletal health declines and contributes to a manifest decrease in their quality of life and survival. Several bisphosphonates have been assessed in patients with bone metastases from breast primary tumour, including alendronate, in order to reduce bone resorption and tumour progression. The present project aims at developing a new nano-drug delivery system for site target, and controlled release of anti-tumour drug. The model developed is a polymer-drug conjugate where the anti-tumour drug Paclitaxel and alendronate, are attached to a natural polymeric carrier, Pullulan, through a spacer. The polymer-drug conjugate designed for controlled release under specific physiological conditions uses two main mechanisms for the release, including an enzymatic hydrolysis and non-enzymatic hydrolysis. The choice of spacers between the polymer and the drug was made so that the drug release only occurs once the system reaches the bone metastasis, using an enzymatic hydrolysis first. When polymer-drug conjugates are elaborated for tumour delivery, the linkage between the drug and the polymer must be necessarily stable under physiological conditions until the tumour target is reached. The drug is then cleaved rapidly to be activated. The colloidal carrier was designed to improve the biopharmaceutical and therapeutic properties of the anti tumoural drug paclitaxel, increasing the paclitaxel solubility in water and targeting the tumour itself. The alendronate bisphosphonate was chosen as a targeting agent to confer a high affinity of the conjugate toward the apatite structure of bone metastases by exploiting the strong bone seeking properties of bisphosphonates, together with the micro-environment of bone metastases, in order to ensure a selective release and accumulation of the anti-tumour drug at the desired site of action; the bone metastases. First, preliminary studies investigated the influence of the time of oxidation of pullulan onto its architecture (molecular weight and polydispersivity). Pullulan was modified by periodate oxidation to obtain a highly reactive polysaccharide towards amines. Given the results of the preliminary studies, it was chosen to prepare a 30% oxidised pullulan. The Cathepsin K sensitive spacer Gly-Gly-Pro-Nle was then synthesised by solid phase peptide synthesis (SPPS) using the Fmoc strategy. Pactitaxel was coupled to the enzyme sensitive spacer and a self-immolative spacer via a six step synthesis to form a prodrug. Consecutively, the bone targeting agent alendronate was PEGylated via an activated carboxylic acid with N-hydroxysuccinimide. Finally, both “prodrugs” were successively anchored to the polysaccharide backbone through Schiff base formation and reductive amination. Once the polymer-drug conjugate, named Pull-PTX-ALN, was fully synthesised, physico-chemical characteristics of the colloid were investigated. All synthesised conjugates were characterised in terms of PTX and ALN contents, purity and stability under physiological conditions. These conjugates showed release of the anti-neoplastic drug only in presence of Cathepsin K at pH 5.5, confirming that, the type of bond chosen allows for the drug release under precise physiological conditions, in the bone metastases environment only. The polymer-drug conjugate bearing PTX and ALN also presented a high affinity for hydroxyapatite in vitro, proving the potential of alendronate as targeting agent. Cytotoxic activity was similar to free drug or in combination with alendronate in 4T1 cells (murine mammary adenocarcinoma cell line), MDA-MB-231 BM (human mammary adenocarcinoma from Bone Metastases cell line) and SAOS-2 (osteosarcoma cell line). Anti-angiogenic properties of alendronate in combination with paclitaxel were also assessed, as well as polymer conjugates challenging the materials with HUVEC (Human Umbilical Vein Endothelial Cells). PTX and ALN together in their free form or conjugated onto Pullulan backbone presented a similar inhibition of proliferation and migration of HUVEC. Additionally, a reduction of capillary-like tube formation, by approximately 40-50%, was observed after 8hour incubation with the primary cell line.<br>RIASSUNTO Nell'ultima fase della malattia, i pazienti che hanno il cancro al seno spesso sviluppano metastasi ossee, una delle principali cause di morte legata al cancro tra le donne nel mondo. Il trattamento comune attualmente utilizzato clinicamente include l'agente anti-neoplastico paclitaxel (PTX) e il bisfosfonato alendronato (ALN). Il paclitaxel è un farmaco anti-neoplastico a quale l’effetto citotossico è attribuito principalmente alla sua capacità di impedire la depolimerizzazione dei microtubuli. La stabilizzazione dei microtubuli mitotici interrompe le funzioni che, in sequenza, blocca la divisione cellulare. Il paclitaxel è approvato per il trattamento del cancro dell'ovaio, della mammella, e del cancro ai polmoni in fase avanzata. Tuttavia, il farmaco anti-tumoure è altamente idrofobico e, di conseguenza, è scarsamente solubile in acqua. Inoltre, la formulazione di paclitaxel attualmente utilizzata in ambito clinico, nota come Taxolo, contiene il farmaco anti-neoplastico disciolto in una miscela di Cremophor EL ed etanolo per aumentarne la solubilità. Tuttavia, la somministrazione di Cremophor EL causa grave dose-limitante tossicità, come ipersensibilità e neuropatia. Infine, l'agente chemioterapeutico soffre di scarsa selettività verso i tumouri, e risulta in danneggiare le cellule normale e sane. Come risultato, molti sforzi sono stati compiuti per lo sviluppo di nuova formulazione di paclitaxel mediante polimerici biocompatibili e biodegradabili. Inoltre, metastasi ossee sono fonte di notevole preoccupazione per i pazienti con carcinoma della mammella in fase avanzata. I pazienti possono affrontare sfide supplementari al cancro come il declino della loro salute del squelette, e contribuisce a una manifesta diminuzione della qualità di vita e sopravvivenza. Alcuni bisfosfonati sono stati valutati in pazienti con metastasi ossee da tumoure primario della mammella, e più particolarmente l'alendronato, al fine di ridurre riassorbimento osseo e progressione del tumore. Il presente progetto mira allo sviluppo di un nuovo nano-sistema di veiculazione di farmaco al sito target, ed il rilascio controllato di farmaco anti-tumoure. Il modello sviluppato è un coniugato polimero-farmaco dove il farmaco anti-tumoure Paclitaxel - utilizzato per trattare il cancro della mammella - e l'alendronato, sono collegati ad un supporto polimerico naturale, il Pullulano, attraverso un distanziatore. Il coniugato polimero-farmaco, progettato per il rilascio controllato in particolare condizione fisiologiche, utilizza due meccanismi principali per il rilascio, compreso un idrolisi enzimatica e un idrolisi non-enzimatica. La scelta del distanziatore tra il polimero e il farmaco è stato fatta in modo che il rilascio del farmaco si verifica solo una volta che il sistema raggiunge le metastasi ossee, rilascio utilizzando una idrolisi enzimatica prima. Quando i coniugati polimero-farmaco sono elaborati per tumoure, il legame tra il farmaco e il polimero deve essere necessariamente stabile in condizioni fisiologiche fino a quando raggiunge il bersaglio tumourale. Il veicolo colloidale è stato progettato per migliorare la biofarmaceutica e le proprietà terapeutiche del farmaco anti-tumoure paclitaxel, aumentando la solubilità in acqua e l'individuazione del tumoure stesso. Il bisfosfonato alendronato è stato scelto come agente di mira a conferire una elevata affinità del coniugato verso la struttura di apatite di metastasi ossee, sfruttando la forte proprietà di grande affinità per l'osso dei bisfosfonati, insieme con il micro-ambiente di metastasi ossee, al fine di garantire un rilascio selettivo e l'accumulo dei farmaci anti-tumouri nel punto di azione desiderato; le metastasi ossee. Primo, gli studi preliminari sono state eseguiti studiando l'influenza del tempo di ossidazione del Pullulano sulla sua architettura (peso molecolare e polydispersivity). Il Pullulano è stato modificato per ossidazione con periodato in vista di ottenere un polisaccaride altamente reattivo verso le ammine. Dagli risultati di studi preliminari, si è scelto di preparare un Pullulano ossidato a 30%. Il distanziatore GlyGlyProNle sensibile alla Catepsina K è stato poi sintetizzato mediante il metodo sintesi di peptidi in fase solida (SPPS) usando la strategia Fmoc. Pactitaxel è stato accoppiato con il distanziatore sensibile all'enzima, ed con un distanziatore auto-immolative tramite una sintesi in sei passi, per formare un profarmaco. Consecutivamente, il targeting delle ossa è stato eseguito con l’alendronato, PEGilato tramite un acido carbossilico attivato con N-idrossisuccinimide. Infine, i due "profarmaci" sono stati successivamente ancorati al backbone del polisaccaride via formazione di base di Schiff e amminazione riduttiva. Una volta che il coniugato polimero-farmaco, chiamato Pull-PTX-ALN, è stato completamente sintetizzato, caratteristiche chimico-fisiche del colloide sono state investigate. Tutti gli coniugati sintetizzati sono stati caratterizzati in termine di contenuto in PTX e ALN, purezza e stabilità in condizioni fisiologiche. Questi coniugati hanno mostrato il rilascio del farmaco anti-neoplastici solo in presenza di catepsina K a pH 5,5 , confermando che il tipo di legame scelto consente il rilascio del farmaco sotto precise condizioni fisiologiche, solo nel ambiente delle metastasi ossee. Il coniugato polimero-farmaco, veiculando PTX e ALN, anche presenta un'alta affinità per l’idrossiapatite in vitro, dimostrando il potenziale del alendronato come agente di mira. L’attività citotossica era simile al farmaco libero o in combinazione con alendronato in linea cellululare 4T1 (linea cellulare adenocarcinoma mammario in murine), MDA-MB-231 BM (linea cellulare del adenocarcinoma mammario umano da metastasi ossee) e SAOS-2 (linea cellulare di osteosarcoma). Le proprietà anti-angiogeniche dell'alendronato in combinazione con paclitaxel sono state valutate con HUVEC (cellule umane endoteliali di vena ombelicale), anche per i coniugati polimero-farmaco. Il PTX e ALN insieme, nella loro forma libera, e coniugati al Pullulano, hanno presentato un'inibizione notevole della proliferazione e della migrazione delle cellule HUVEC. Inoltre, una riduzione della formazione di tubi capillari di circa 40-50 %, è stata osservata dopo 8 ore di incubazione con la linea cellulare.

Drug delivery is an increasingly investigated field, aiming at distributing a therapeutic substance precisely to the area, tissue or cell where needed and consequently controlling its release, thus guaranteeing optimal efficiency. Besides, this targeted action can also bring significant advantages in other diverse sectors. The delivery systems designed and fabricated in this work were meant to overcome some of the issues related to current therapies for different illnesses. Specifically, polylactic acid (PLA) was exploited to produce nanoparticles which were functionalized and encapsulated in polyelectrolyte Layer-by-Layer (LbL) microcontainers to support mucolytic enzymes’ action, with the aim of overcoming thick mucus barriers in cystic fibrosis patients’ upper airways, and reducing their viscosity. Moreover, nanoparticles were also modified with cyclodextrins to carry small hydrophobic anti-inflammatory drugs. Alginate was used to produce multicompartment hydrogels containing LbL capsules loaded with a chemotherapeutic drug, to achieve a local prolonged delivery in solid tumour resection cavities. However, as a general consideration, these systems can act as delivery carriers for a wide variety of drugs and can be exploited for various purposes, also other than the delivery of therapeuticals, which still remains the main focus of this thesis. An example of the engineering point of view is represented by LbL capsules, which can carry nanoparticles as well as small water-soluble chemotherapeutic drugs with slight or no modification of the production procedure, as above mentioned. Another example, showing strongly different fields of application of the same system, is constituted by cyclodextrins-modified PLA nanoparticles, which demonstrated the ability to complex with an anti-inflammatory drug, namely ketoprofen, as well as with an industrial pollutant, namely alizarin red s, without being modified. Finally, PLA was also used in a novel approach to obtain specific geometries of microchambers and microcapsules for the retention of small hydrophilic molecules. In this case, the great potential relies on the fabrication technique used for these carriers. Specifically, the use of PDMS molds offers a reproducible fabrication of differently sized and shaped bottomless microchambers and capsules. Once the stamps are covered with the chosen polymer but still open, they can be loaded with various techniques, from the in-liquid to the dry powder loading. This allows to fill those carriers with smaller or bigger molecules, being water soluble or insoluble, potentially using almost all the available inner volume of the carrier, which is a reversal of the traditional carrier filling in drug delivery. This production method also pavents the way for industrial scalability of drug delivery systems, potentially overcoming some of the biggest obstacles to this modern way of re-thinking pharmaceutical dosages. The overall findings of this thesis support the efforts in making drug delivery carriers a greatly promising tool for pharmaceutical therapies and dosages. Specifically, biopolymers can allow a great advance in the fields of drug delivery and materials engineering.

[EN] Nowadays, one of the biggest concerns that permanently keep the attention of main important sectors of human society is health. Modern medical science is compromised with not only providing good adequate treatments but also effective specific solutions for each type of disease or human pathology. In this direction, innovative approaches like tissue engineering or regenerative medicine, controlled drug delivery systems and nanomedicines emerge to bring alternatives to situations hard to solve with conventional treatment and strategies, including the replacement of damaged or diseases tissues and/or organs. Specifically, this research is mainly aimed to design a combined system for controlled, stable and localized release of therapeutic agents that are able to exert their effect selectively on the area that warrants treatment. This construct will have enough versatility to be adapted to almost any kind of treatment, from cancer to tissue regeneration, always that the key requirement of the treatment was the need to provide the treatment of localized, stable and controlled manner. With the purposes of making easier the understanding as well as the design of the system, I was decided, for the proof of concept, to use drugs and materials with known activity applied on tissue regeneration and for the treatment of chronic wounds. The system in question consists of three main elements: 1) The first element is the polymer conjugates of therapeutic agents, which contribute to increasing the selectivity of the therapeutic action of the drug, as well as improved stability, bioavailability and biocompatibility thereof. If the drug is hydrophobic, conjugation contributes to increase its solubility in water, and in the case of proteins used as therapeutic agents, the combination helps reduce the body's immune response, increasing the chance of successful of the treatment. 2) The second element are the biodegradable polymeric microparticles, which in this case act like encapsulation agents for polymeric conjugate , thus allowing to have a second control point in the release kinetics of the therapeutic agents . Simultaneously, the microparticles also play a role in modifying the texture of the final construct, ascribing mechanical and physicochemical properties that help to improve some biological properties of the final material, such as the affinity, adhesion and cell proliferation. 3) The third element consists of a nanoporous membrane made of a biodegradable polymer by electrospinning, which constitute the unifier element of the whole system. This membrane provides manageability to the construct and is itself the last point of control in the release kinetics of the therapeutic agent or agents. Besides, it must be biocompatible and stable at ambient conditions, since this probably is going to be exposed to the environment while protecting the wound, in the case of this kind of application. These three elements, which themselves are complex systems separately, are systematically combined to achieve a synergistic relationship between them so that each one power the qualities of the other two. The resulting construct was characterized and it demonstrated to have characteristic properties that can be used as a control parameter during manufacture of this new material. Also, preliminary biological studies developed "in vitro" indicated that the proposed system may be a good candidate for deeper studies as alternative treatment for chronic wounds and other pathologies that require localized administration for long periods of time.<br>[ES] Actualmente, una de las mayores preocupaciones que permanentemente laman la atención de los principales sectores de la sociedad humana es la salud. La ciencia médica moderna está comprometida no solo con suministrar tratamientos adecuados, sino más bien ofrecer soluciones efectivas y específicas para cada tipo de enfermedad o patología humana. En este sentido, estrategias innovadoras como la ingeniería de tejidos o la medicina regenerativa, los sistemas de liberación controlada de fármacos y las nanomedicinas, surgen como buenas alternativas para abordar situaciones difíciles de resolver aplicando los tratamientos y estrategias terapéuticas convencionales, como es el caso cuando se hace necesario reemplazar tejidos o incluso órganos dañados por algún traumatismo o enfermedad. Concretamente, el presente trabajo de investigación tiene por objetivo principal diseñar un sistema combinado para la liberación controlada, estable y localizada de agentes terapéuticos que sean capaces de ejercer su efecto de forma selectiva sobre la zona que amerita el tratamiento. Este constructo tendrá la versatilidad suficiente como para poder adaptarse a casi cualquier tipo de tratamiento, desde el cáncer hasta la regeneración de tejido, siempre que el requisito clave del tratamiento sea la necesidad de suministrar el tratamiento de manera localizada, estable y controlada. Para efectos de facilitar la compresión y el diseño del sistema se escogió para la prueba de concepto materiales y fármacos asociados a la regeneración de tejidos, como tratamiento para casos de heridas crónicas. El sistema en cuestión está constituido por tres elementos principales: 1) El primer elemento son los conjugados poliméricos de agentes terapéuticos que contribuirán a aumentar la selectividad de la acción terapéutica del fármaco, así como también a mejora la estabilidad, biodisponibilidad y biocompatibilidad de los mismos. En caso de que el fármaco sea hidrofóbico, la conjugación contribuye a aumentar su solubilidad en agua, y en el caso de usar proteínas como agentes terapéuticos, la conjugación contribuye a disminuir la respuesta inmunológica del cuerpo incrementando las posibilidad de éxito del tratamiento. 2) El segundo elemento son micropartículas poliméricas biodegradables, que en este caso actúan con agentes de encapsulación para los conjugados poliméricos, permitiendo así contar con un segundo punto de control en la cinética de liberación de los agentes terapéuticos. Simultáneamente, las micropartículas también cumplen un papel de modificador de la textura del constructo final, adjudicándole propiedades mecánica y fisicoquímicas que contribuyen a mejorar las propiedades biológicas del material final, como son la afinidad, la adhesión y la proliferación celular. 3) El tercer elemento consiste en una membrana polimérica biodegradable nanoporosa hecha por electrospinning, que constituyen el elemento unificados del sistema, aporta manejabilidad al constructo y es en sí mismo el último punto de control en la cinética de liberación del agente terapéutico. Este último debe ser biocompatible y estable en condiciones ambientales, puesto que probablemente este expuesto al ambiente mientras protege la herida, en el caso concreto de este tipo de aplicación. Estos tres elementos, que en sí mismos constituyen sistemas complejos por separado, se han combinado sistemáticamente para alcanzar una relación sinérgica entre ellos de manera que cada uno potencia las cualidades de los otros dos. El constructo resultante se caracterizó demostrando tener propiedades características que se pueden utilizar como parámetro de control durante la fabricación del mismo. Así mismo estudios in vitro del sistema desarrollado señalan que puede ser un buen candidato para el tratamiento de heridas crónicas entre otras patologías que requieran tratamientos localizados.<br>[CAT] Actualment, una de les majors preocupacions que permanentment llepen l'atenció dels principals sectors de la societat humana és la salut. La ciència mèdica moderna està compromesa no solament amb subministrar tractaments adequats, sinó més aviat oferir solucions efectives i específiques per a cada tipus de malaltia o patologia humana. En aquest sentit, estratègies innovadores com l'enginyeria de teixits o la medicina regenerativa, els sistemes d'alliberament controlat de fàrmacs i les nanomedicines, sorgeixen com a bones alternatives per a abordar situacions difícils de resoldre aplicant els tractaments i estratègies terapèutiques convencionals, com és el cas quan es fa necessari reemplaçar teixits o fins i tot òrgans danyats per algun traumatisme o malaltia. Concretament, el present treball de recerca té per objectiu principal dissenyar un sistema combinat per a l'alliberament controlat, estable i localitzada d'agents terapèutics que seguen capaços d'exercir el seu efecte de forma selectiva sobre la zona que amirita el tractament. Aquest constructe tindrà la versatilitat suficient com per a poder adaptar-se a quasi qualsevol tipus de tractament, des del càncer fins a la regeneració de teixit, sempre que el requisit clau del tractament sega la necessitat de subministrar el tractament de manera localitzada, estable i controlada. Per a efectes de facilitar la compressió i el disseny del sistema es va escollir per a la prova de concepte materials i fàrmacs associats a la regeneració de teixits, com a tractament per a casos de ferides cròniques. El sistema en qüestió està constituït per tres elements principals: 1) El primer element són els conjugats polimèrics d'agents terapèutics que contribuiran a augmentar la selectivitat de l'acció terapèutica del fàrmac, així com també a millora l'estabilitat, biodisponibilitat i biocompatibilitat dels mateixos. En cas que el fàrmac sega hidrofòbic, la conjugació contribueix a augmentar la seua solubilitat en aigua, i en el cas d'usar proteïnes com a agents terapèutics, la conjugació contribueix a disminuir la resposta immunològica del cos incrementant les possibilitat d'èxit del tractament. 2) El segon element són microparticles polimèriques biodegradables, que en aquest cas actuen amb agents d'encapsulació per als conjugats polimèrics, permetent així comptar amb un segon punt de control en la cinètica d'alliberament de l'agent terapèutics. Simultàniament, les microparticles també compleixen un paper de texturitzant del constructe final, adjudicant-li propietats mecànica i fisicoquímiques que contribueixen a millorar la propietats biològiques del material final, com són l'afinitat, l'adhesió i la proliferació cel·lular. 3) El tercer element consisteix en una membrana polimèrica biodegradable nanoporosa feta per electrospinning, que constitueixen el element unificats del sistema, aporta manejabilitat al constructe i és en si mateix el ultimi punt de control en la cinètica d'alliberament de l'agent terapèutic. Aquest últim ha de ser biocompatible i estable en condicions ambientals, ja que probablement aquest exposat a l'ambient mentre protegeix la ferida, en el cas concret d'aquest tipus d'aplicació. Aquests tres elements que en si mateixos constitueixen sistemes complexos per separat, s'han combinat sistemàticament per a aconseguir una relació sinergètica entre ells de manera que cadascun potencia les qualitats dels altres dos. El constructe resultant es va caracteritzar demostrant tenir propietats característiques que es poden utilitzar com a paràmetre de control durant la fabricació del mateix. Així mateix estudis in vitro del sistema desenvolupat assenyalen que pot ser un bon candidat per al tractament de ferides cròniques entre altres patologies que requeriren tractaments localitzats.<br>Rodríguez Escalona, GDJ. (2016). DEVELOPMENT OF CONTROLLED DRUG DELIVERY SYSTEMS OF POLYMERIC NANOMEDICINES ASSOCIATED TO SCAFFOLDS FOR TISSUE REGENERATION [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/63231<br>TESIS

To increase the effectiveness of conventional radiotherapy in the treatment of cancer, different drugs can be administered. The aim of this project is to investigate biodegradable polyanhydride carrier matrices (PCPP-SA; 20:80) as a localized slow release delivery system for halogenated pyrimidines, in our case Bromodeoxyuridine (BrdU). Our in vitro experiments show that RIF-1 cells which have incorporated BrdU into their DNA over 4 doublings show significant increase in the initial slope (alpha-value) of their radiation cell survival curves, indicating an increase in radiosensitivity. To investigate the radiosensitization potential of BrdU in vivo, biodegradable BrdU/polymer combinations (20% w/w) were prepared and implanted directly into RIF-1 tumors, grown subcutaneously on the backs of C3H/Km mice. Clonogenic/excision assays were done with these tumors exposed to BrdU/polymer implants for several cell cycles before irradiation in situ to determine the extent of radiosensitization on the basis of cell survival. Tumor growth delay (TGD) measurements were also used as an index of tumor control following different treatments (single dose or fractionated doses) with and without the drug/polymer implants. All results indicate that BrdU, combined with radiation, increases TGD, while having no effect on non-irradiated tumors. The extent of substitution of thymidine by BrdU in DNA were also determined. This project was supported by the National Cancer Institute of Canada.

Osteomyelitis is an infection of bone or bone marrow, usually caused by pyogenic bacteria. It can cultivate by hematogen way or it can cultivate by the help of local soft tissue infection. Osteomyelitis often requires prolonged antibiotic therapy and surgery. But for therapy<br>antibiotic must reach to effective dose in the bone. So that<br>for prevention and treatment of osteomyelitis controlled antibiotic release systems can be used. These systems have been developed to deliver antibiotics directly to infected tissue. As a carrier material<br>polymers are widely use. Polymer can be biodegradable or non biodegradable. The advantage of biodegradable polymers is<br>you do not need a second surgery for the removal of the carrier material from the body. In this study<br>vancomycin loaded PLLA/TCP composites were developed and characterized to treat implant related chronic osteomyelitis in experimental rat osteomyelitis model. Some of the composites were prepared by coating the vancomycin loaded composites with PLLA to observe the difference between the coated and uncoated composites. Also, some composites were developed free from the vancomycin to determine the biocompatibility of the composite for the bone tissue. The coating extended the release of the vancomycin up to 5 weeks and changed the surface morphology of the composites. According to the cell culture studies, vancomycin loaded PLLA/TCP composites promoted cell adhesion, cell proliferation and mineralization so<br>the composite was biocompatible with bone tissue. Radiological and microbiological evaluations showed that vancomycin loaded and coated vancomycin loaded PLLA/TCP composites inhibited MRSA proliferation and treat implant related chronic osteomyelitis.

Stable single-unit recordings from the nervous system using microelectrode arrays can have significant implications for the treatment of a wide variety of sensory and movement disorders. However, the long-term performance of the implanted neural electrodes is compromised by the formation of glial scar around these devices, which is a typical consequence of the inflammatory tissue reaction to implantation-induced injury in the CNS. The glial scar is inhibitory to neurons and forms a barrier between the electrode and neurons in the surrounding brain tissue. Therefore, to maintain long-term recording stability, reactive gliosis and other inflammatory processes around the electrode need to be minimized. This work has succeeded in the development of neural electrode coatings that are capable of sustained release of anti-inflammatory agents while not adversely affecting the electrical performance of the electrodes. The effects of coating methods, initial drug loadings on release kinetics were investigated to optimize the coatings. The physical properties of the coatings and the bioactivity of released anti-inflammatory agents were characterized. The effect of the coatings on the electrical property of the electrodes was tested. Two candidate anti-inflammatory agents were screened by evaluating their anti-inflammatory potency in vitro. Finally, neural electrodes coated with the anti-inflammatory coatings were implanted into rat brains to assess the anti-inflammatory potential of the coatings in vivo. This work represents a promising approach to attenuate astroglial scar around the implanted silicon neural electrodes, and may provide a promising strategy to improve the long-term recording stability of silicon neural electrodes.

La salute delle strutture molli e dure del cavo orale è essenziale non solo per preservare le funzioni ad esse direttamente associate, ma anche per promuovere la salute generale dell’organismo. Tra le problematiche di maggiore interesse clinico a carico della cavità orale ritroviamo: i) le complicazioni post-operatorie che possono verificarsi a seguito di comuni avulsioni dentali che, se non trattate tempestivamente, possono sfociare in gravi parodontiti; ii) i fenomeni di osteonecrosi a carico di mascella e mandibola associate a trattamenti farmacologici nonché alla radioterapia; iii) il carcinoma orale a cellule squamose (OSCC) che è tra i più aggressivi tumori del collo e della testa, caratterizzato dal più basso tasso di sopravvivenza a 5 anni. Va inoltre presa in considerazione la posizione anatomica del cavo orale che, essendo facilmente accessibile dall’esterno, è suscettibile ad infezioni batteriche che possono compromettere uno stato di salute già debilitato e/o peggiorare la condizione clinica delle problematiche sopra citate. Nel trattamento delle affezioni del cavo orale è di fondamentale importanza ottenere una rapida remissione della sintomatologia, favorendo la rigenerazione del tessuto leso e prevenendo le complicazioni infettive mediante una terapia mirata, efficace e localizzata. Tuttavia, le strategie terapeutiche attualmente in uso sono spesso invasive e in alcuni casi meramente palliative (es. rimozione chirurgica del tessuto necrotico anche osseo), o spesso la necessità di ricorrere a terapie farmacologiche aggressive non scevre da effetti avversi anche gravi può contribuire ad un peggioramento di una condizione patologica preesistente. Per superare gli inconvenienti dati dai trattamenti convenzionali, recentemente è stato proposto l’utilizzo di sostanze naturali di origine vegetale aventi comprovate proprietà terapeutiche benefiche (es. antiossidanti, antinfiammatorie, antitumorali, antibatteriche), capacità di stimolazione dei processi di rigenerazione tissutale, e soprattutto, effetti collaterali trascurabili. Tra le varie classi di composti naturali che potrebbero rispondere a tali requisiti, i polifenoli sono quella di maggiore interesse scientifico. Si tratta di un gruppo di molecole molto eterogeneo accomunato chimicamente dalla presenza di uno o più gruppi fenolici. Sebbene i polifenoli si trovino in molteplici fonti alimentari e le loro svariate proprietà benefiche siano ben note, il loro utilizzo in ambito clinico è ancora una sfida aperta a causa delle loro caratteristiche chimico-fisiche e farmacocinetiche generalmente sfavorevoli, quali instabilità chimica e fisica, quando soggette ai fenomeni ambientali come le radiazioni ultraviolette, temperatura elevata o pH fortemente acido o alcalino, scarsa solubilità in ambiente acquoso, elevata suscettibilità al metabolismo epatico e, quindi, bassa biodisponibilità a seguito di somministrazione orale. Per superare tali limiti e rendere somministrabili ed efficaci i polifenoli è quindi auspicabile la realizzazione di drug delivery platform o carrier in grado di incorporare efficacemente tali attivi, preservarne l’integrità strutturale e funzionale e modularne il rilascio al sito target. Inoltre, per promuovere la guarigione dagli stati patologici sopra elencati, può risultare utile la co-somministrazione di polifenoli ed antibatterici tra quelli già utilizzati in chirurgia orale. Tenendo in considerazione queste premesse nel presente lavoro di dottorato sono stati realizzati innovativi sistemi di veicolazione capaci di incorporare polifenoli quali Curcumina, Quercetina e Resveratrolo da soli o in co-somministrazione con antibiotici quali il Metronidazolo e la Ciprofloxacina, per il trattamento localizzato delle suddette patologie associate al cavo orale. Una strategia per la veicolazione dei polifenoli consiste nella loro incapsulazione in sistemi micro e nanoparticellari. A tal fine sono state realizzate microparticelle polimeriche contenenti Resveratrolo con la tecnica dello Spray Drying, ottimizzando accuratamente i parametri operativi al fine di ottenere particelle sferiche, di dimensione omogenea ed uniformi in termini di contenuto in attivo. Tale strategia ha consentito la completa amorfizzazione del Resveratrolo, incrementandone notevolmente la solubilità in ambiente acquoso, e promuoverne la permeabilità attraverso la mucosa sublinguale. I Carrier Lipidici Nanostrutturati (NLC), costituiti da particelle di dimensioni nanometriche, si sono rivelati un altro sistema di veicolazione dei polifenoli particolarmente promettente, proprio grazie alla loro natura lipidica che ben si è adattata alle caratteristiche chimico-fisiche dei polifenoli. Un’attenta selezione dei componenti lipidici e del bilanciamento degli stessi in relazione al tipo ed alla quantità di polifenolo da incapsulare, ha consentito la preparazione di miscele omogenee, aventi temperatura di rammollimento opportuna (stabilità, storage e maneggevolezza) ma soprattutto contenenti il polifenolo nella sua forma amorfa. Sono stati pertanto preparati e caratterizzati diversi sistemi NLC contenenti rispettivamente Curcumina, Quercetina e Resveratrolo. L’ottimizzazione della tecnica di preparazione top-down ad alta energia caratterizzata da omogeneizzazione seguita da sonicazione ad alte frequenze, ha portato alla produzione di nanoparticelle riproducibili ed omogenee (<500 nm, PDI < 0.600), caratterizzate da un’elevata efficienza di incapsulazione (>95%) ed in grado di controllare il rilascio degli attivi secondo cinetiche ben definite. Per consentire la co-somministrazione dei polifenoli (lipofili) con gli antibiotici precedentemente menzionati (idrofili), sono stati ulteriormente realizzati dei sistemi nanocompositi sotto forma di spugne bioerodibili, costituite da una matrice polimerica biocompatibile e bioerodibile (a base di Chitosano o Acido Ialuronico, e PVP K90) all’interno della quale sono state intrappolate le nanoparticelle lipidiche. I nanocompositi, essendo formulazioni polverulente, hanno mostrato diverse caratteristiche favorevoli, tra cui: omogeneità, elevata porosità, capacità di promuovere l’accumulo degli attivi nei tessuti del cavo orale ed elevata stabilità nel tempo, preservando così i polifenoli dalla degradazione. Inoltre, la “trasformazione” delle dispersioni acquose di NLC in un sistema anidro porta all’ottenimento di una polvere secca estremamente semplice da manipolare ed applicare, consentendo di dosare i principi attivi in modo accurato e riproducibile. Studi in vitro, hanno dimostrato, inoltre, la citocompatibilità delle spugne bioerodibili a base di Curcumina, coì come la citocompatibilità delle NLC cariche di Resveratrolo con i fibroblasti murini, mentre le spugne a base di Quercetina e Ciprofloxacina hanno evidenziato proprietà antibatteriche e antibiofilm nei confronti dello Staphilococcus aureus superiori all’antibiotico in forma libera.Parallelamente, è stata impiegata la tecnica della stampa 3D per la realizzazione di scaffold polimerici carichi sia di Curcumina, in cui l’aggiunta di beta-tricalcio fosfato (bioceramica), è stata in grado di influenzare positivamente le caratteristiche dello scaffold, aumentandone la porosità e promuovendo la stabilità della Curcumina in fase di preparazione. In conclusione, il lavoro di ricerca svolto ha portato allo sviluppo tecnologico, da una parte, di valide ed efficienti delivery platform nano- e micrometriche per la veicolazione dei polifenoli e, dall’altra, alla produzione di sistemi di drug delivery macroscopici (nanocompositi e scaffold) potenzialmente utili per il trattamento delle patologie del cavo orale.

L’encapsulation de principes actifs (PA) dans des liposomes est utilisée dans de nombreux domaines tels que les industries pharmaceutiques et cosmétiques. Les liposomes sont des systèmes d’administration de médicaments utilisés pour leur relargage contrôlé des PA. Pour augmenter l’efficacité de peptides comme PA, nous cherchons à optimiser des liposomes en jouant à la fois sur leur composition et la structure des peptides. Les paramètres à améliorer sont leurs interactions, l’efficacité d’encapsulation et la cinétique de relargage. Pour atteindre cet objectif, j’ai évalué l’intérêt de la spectroscopie par Résonance Magnétique Nucléaire (RMN) pour caractériser les peptides, les liposomes et leurs comportements pendant le relargage. Les peptides utilisés dans cette étude sont dérivés de l’apeline, qui a un intérêt pour la régulation homéostatique du système cardiovasculaire. Les structures des liposomes et des peptides ainsi que leurs interactions ont été étudiées par RMN ¹H et ³¹P et par cryo-EM. J’ai montré que les méthodes de diffusion par RMN, en s’appuyant sur la taille apparente des molécules, permettent de différencier les compartiments internes et externes des liposomes et de suivre les cinétiques in situ en temps réel de relargage de peptide, sans perturber le processus. Les cinétiques de relargage ont aussi été quantifiées par intégration spectrale de spectres RMN ¹H. J’ai aussi montré que la méthode de préparation des liposomes avait un impact sur leur structure, leur cinétique de relargage et leurs interactions avec des peptides. L’addition d’une chaîne lipidique augmente les interactions avec les liposomes, mais la longueur et le type de chaîne induisent peu de différences. Les outils de RMN mis en place pourront être étendus à d’autres PA et systèmes d’administration pour des applications pharmaceutiques et cosmétiques<br>The encapsulation of active ingredients (AI) in liposomes is used in several domains such as pharmaceutical and cosmetic industries. Liposomes are drug delivery systems (DDS) used for a controlled release of AIs. To increase the efficiency of peptide drugs, I aim at designing optimized peptide/liposomes formulation by playing both on their composition and peptide structure. Potential parameters to be improved are their interactions, encapsulation efficiency and release kinetics. To reach this goal, I explored the potentiality of Nuclear Magnetic Resonance (NMR) spectroscopy to characterize peptides, liposomes and their behavior during release. The AIs used in this study are apelin-derived peptides that are of interest for homeostasis regulation of the cardiovascular system. Liposome and peptide structures as well as their interactions were characterized by ¹H and ³¹P NMR and cryo-EM. I showed that diffusion NMR methods that report on the apparent size of molecules can discriminate between the inner and the outer space of liposomes and for release quantification in-situ and in real-time without perturbing the process. Moreover, ¹H NMR spectra were used to monitor and quantify peptide release kinetics by spectral integration. I showed that the preparation method of liposomes drastically impacts their structure, release kinetics and interactions with peptides. Addition of a lipid chain increases the interaction with the liposomes, but the type and length of the chain induce only few differences. This approach could certainly be extended to other AIs and DDSs used for pharmaceutical and cosmetic applications

Les matériaux hydroxydes doubles lamellaires (HDL) sont une classe d'argiles anioniques synthétiques dont la structure est basée sur celle du brucite Mg(OH)2 dans lesquelles une partie des cations métalliques divalents sont été remplacés par des ions trivalents donnant ainsi des feuillets chargés positive. Cette charge est équilibrée par l'intercalation d'anions dans la région interlamellaire hydratée. Les identités et les rapports des cations di- et trivalents et l'anion interlamellaire peuvent être varié sur une large gamme, donnant lieu à une large classe de matériaux isostructurales. Le matériau d’origine de cette classe est l’hydrotalcite (HT) et les HDL sont par conséquent également connus comme des matériaux de type hydrotalcite. Bien que les caractéristiques de base de la structure soient bien comprises, des aspects structurels détaillés ont fait l'objet de certaine controverse dans la littérature afin de maîtriser leurs propriétés et leurs applications potentielles. Dans ce travail de thèse nous avons retenu deux types de HDL MgAl et ZnAl qui ont été largement introduits dans diverses applications, tels que la sorption des molécules d'intérêt biologique (enzyme et médicament) et l'élaboration d'électrodes. La spécificité de ce travail repose sur l’immobilisation d’une enzyme modèle, la lactate déshydrogénase dans ces deux matrices ainsi qu’un médicament anti-bactérien, la berbérine, afin d’étudier les interactions entre ces deux biomolécules et la phase HDL introduite et de répondre à leurs exigences d'applications dans le domaine médical. Dans un second temps nous avons tenté d’étudier les deux phases mentionnées de plus en plus fine en termes de structure, morphologie et profil électrochimique en vue de les employer en tant que matériaux d’électrode pour le développement de biopile<br>DHs are a class of synthetic anionic clays whose structure is based on brucite-like layers Mg(OH)2 inwhich some of the divalent cations have been replaced by trivalent ions giving positively-charged sheets.This charge is balanced by intercalation of anions in the hydrated interlayer regions. The identities andratios of the di- and trivalent cations and the interlayer anion may be varied over a wide range, giving rise toa large class of isostructural materials. The parent material of this class is the naturally occurring mineralhydrotalcite and LDHs are consequently also known as hydrotalcite-like materials. Although the basicfeatures of the structure are well understood, detailed structural aspects have been the subject of somecontroversy in the literature. In this thesis, we have selected two types of LDH, MgAl and ZnAl, which havebeen widely introduced in various applications, such as sorption of molecules of biological interest (enzymeand drug) and the development of electrodes. The specificity of this work lies on the immobilization of amodel enzyme, lactate dehydrogenase in both matrices as well as an anti-bacterial drug, berberine, inorder to study the interactions between these two biomolecules and the introduced LDH phase and tobetter address their challenges of applications in the medical field. Second, we have tried to study the twophases mentioned above more and more accurately in terms of structure, morphology and electrochemicalprofile in order to use them as electrode materials for microbial fuel cell device

In this study, attempts were made to develop computer controlled iontophoretic drug delivery system. The iontophoretic set up was made using NI SPEEDY33 voltage buffer, constant current source and specially designed diffusion cell. The stability of constant current source was checked by varying the load resistance and measured the voltage across it. Different wave forms were generated using NI SPEEDY 33 and LABVIEW 8.6 and they were employed in the in vitro drug delivery. The effectiveness of iontophoretic set up was tested using span 80-tween 80 based sunflower oil organogels. The organogels were characterized using SEM, FTIR and XRD studies. Thermal, textural, visco-elastic and electrochemical properties of the organogels were also studied. The in vitro drug release studies were performed using different wave forms viz., sinusoidal waveform ,square waveform and triangular waveform. and also the half wave and full wave of sine waveform . The active drug release from the gels was compared against passive diffusion. The drug release followed the zero order kinetics suggesting the diffusion mediated release. The Krossmeyer-Peppas kinetics suggested the anomalous release of drugs during active diffusion of drugs. The results suggest that the developed iontophoretic set up has a huge potential in the iontophoretic drug delivery system.

The current study describes the development of wireless controlled iontophoretic drug delivery system. The control system was made using ZigBee communication protocol. The circuit performance analysis of the current injecting circuit was performed to ascertain minimal error combined with high efficiency. Finally, the developed controlled system was used to manipulate the functioning of the two independent iontophoretic drug delivery systems. In gist, a wireless controlled drug delivery system based on ZigBee communication protocol was developed and tested successfully.

Multiple dose regimens are frequently required to optimize therapy; however, such therapy is frequently undermined by poor patient adherence. In fact, patient adherence is inversely related to the number of doses a patient is asked to take each drug. Consequently, great efforts are under way to develop drug delivery systems that are able to release drugs over an extended time interval; this could offer considerable benefits including reducing administration frequency. This dissertation describes multiple dose platforms designed to deliver a variety of drugs as a single oral administration are described in this dissertation. We believe these drug delivery systems can be used to enhance patient compliance and achieve better therapeutic outcomes. We developed and tested a novel gastroretentive pulsatile drug delivery platform. This platform could deliver multiple unit doses of a drug in a pulsatile pattern and be controlled by dissolution/erosion of a lag-time interval layer. The platform was designed to be retained in the stomach whilst pulsing drug at various timed intervals. This would allow each dose of the drug to release above or within an optimized absorption window over an extended period of time. To assure the robustness and reproducibility of the platform, various in vitro dissolution studies and physical stability tests were performed and evaluated through drug release characteristics, buoyancy, and structural integrity evaluations. The applicability of the novel multiple dose platform was demonstrated by providing repeated release profiles of ciprofloxacin and verapamil in a single, once-daily delivery system. Ultimately, this dissertation demonstrates that a novel multiple dose platform could be a suitable alternative dosing strategy for a variety of drugs to improve patient adherence and treatment efficacy.<br>text

碩士<br>國立臺灣大學<br>電機工程學研究所<br>89<br>Abstract Drug delivery system with ultrasound has widely been used in clinical therapy, for example, transdermal drug delivery, and sonodynamic therapy, etc. Good drug delivery system requires the suitable administration pathway, targeting to the diseased organ, increased drug efficacy and reduced side effects. We will set up and evaluate a new drug delivery system to control drug release by using ultrasonic cavitation and drug carrier as liposome. In this study, we will produce our drug carrier — liposome, and obtain the optimal conditions of cavitation occurrence by analyzing and processing the reflective acoustic signal of liposomes in order to make liposomes collapse around the diseased organ or tissue. We change the experimental conditions, for example, transmitting cycles, PRF length, transmitting acoustic amplitude and frequency, etc., in order to obtain the optimal conditions of liposome detection and cavitation. Finally, we will discuss the technical requirements of this drug delivery system, and its safety and applications.

碩士<br>淡江大學<br>化學工程與材料工程學系碩士班<br>100<br>In this study, optical-controlled thermal-responsive composites based on thermo-responsive polymers (TRP) and gold nanorod (GNR) were prepared as a potential carrier for drug delivery system. When the composites were irradiated by near IR laser which could penetrate deep into tissues, the GNR could transform the absorbed light into heat due to the surface plasmon effect (SPR) and thus raised the temperature, which leaded to the volume shrinkage of the TRP and thereby releasing the encapsulated drug. Copolymers based on N-isopropyl acrylamide (PNIPAAm) and telechelic oligo(ethylene glycol) methyl ether acrylate (OEGA) were synthesized as the TRP. The OEGA was added into the reaction system to modulate the lower critical solution temperature (LCST) and increase the biocompatibility of the resulting copolymers. First, NIPAAm monomer and semi-telechelic OEGA with different molar ratios were dissolved in DMF. Subsequently, 2-(dodecyl thiocarbonothioylthio)-2-methylpropionic acid (DMP) as the chain transfer agent (CTA) and 4,4′-azobis(4-cyanovaleric acid) (ACVA) as the initiator were added into the solution to undergo the reversible addition-fragmentation chain transfer (RAFT) polymerization. The produced HOOC-P(N-OEG)-CTA copolymers with α-carboxylic acid and ω-dodecyltrithiocarbonate end groups were proved to have a very low dispersity in molecular weight. When the feeding molar ratio of the OEGA was 0.06, the resulting HOOC-P(N-OEG)-CTA copolymer had a LCST value of 38.5°C, slightly higher than the physiological temperature. Subsequently, the terminal trithiocarbonate group of the copolymers was reduced by NaBH4 to obtain thiol-terminated thermo-responsive copolymers. However, it was found that the acrylate side group of the OEGA was reduced as well to carboxylic and even hydroxyl groups, resulting in a decrease in the LCST value. Opto-thermal effect was induced by surface plasmon effect of gold nanorod (GNR). Using the seed-mediated growth method, the synthesized GNR was very uniform in both size and shape with a dimension of 35.9(±4.6) nm in length and 10.2(±1.26) nm in width, thus having an aspect ratio (AR) of 3.52(±0.61) and a corresponding SPL,max of 793 nm. Both the HOOC-PNIPAAm-CTA (MW=8503 kDa, PDI=1.12, LCST=31.6°C) and HOOC-P(N-OEG6)-CTA (MW=11512 kDa, PDI=1.01, LCST=38.5°C) with different amounts were tried to graft onto the GNR to produce opto-thermal responsive TRP/GNR composites. It was found the TRP/GNR composites prepared by grafting 50 mg TRP onto 3 mL GNR (2.11×10-10 M) at pH7 for 24 h had the best stability. STEM results confirmed that the trithiocarbonate group could be adsorbed onto the surface of GNR, and the TEM image showed that the GNR was protected by a surrounding polymer layer. After grafting, the HOOC-PNIPAAm-CTA/GNR and HOOC-P(N-OEG6)-CTA)/GNR had LSCT values at 31.4°C and 38.6°C, respectively, indicating that the grafting process did not affect the LCST values. The TRP/GNR solution was tested for the near-IR irradiation-induced thermo-responsibility and cell compatibility. Because of the surface plasmon effect of GNR, the irradiation of near-IR (808 nm, 1000 mW) for 5 min could induce the temperature to rise from 25°C to 43°C. The thermo-responsibility was also reversible during five test cycles. Moreover, the protection polymer layer could decrease the cytotoxicity of the GNR. Cell viability was increased from 44% for the GNR to 86% and 93% for the HOOC-PNIPAAm-CTA/GNR and HOOC-P(N-OEG6)-CTA/GNR, respectively.

Hydrophobic drug paclitaxel nanoparticles (PAX NPs) and pH sensitive hydrogels were prepared in this study to build a colon targeting nanoparticle based drug delivery system for oral administration. Negative charged PAX NPs at the size of 110 +/- 10 nm were fabricated, characterized and then encapsulated in synthetic / biomacromolecule shell chitosan, dextran-sulfate using a layer by layer (LbL) self-assembly technique. Surface modifications were performed by covalently conjugating with poly (ethylene glycol) (H2N-PEG-carboxymethyl, Mw 3400) and fluorescence labeled wheat germ agglutinin (F-WGA), so as to build a biocompatible and targeted drug delivery system. Extended release of drug paclitaxel can be realized by adding more polyelectrolyte layers in the shell. High cell viability with PEG conjugated and high binding capacities of WGA modified nanoparticles with Caco-2 cells were observed. Preliminary study on stability of the nanoparticles in suspension at different pH was also performed. Two dextran based pH sensitive and enzyme degradable hydrogels: dextran maleic acid (Dex-MA), and glycidyl methacrylated dextran (Dex-GMA) were synthesized for oral delivery of nanoparticles. Hydrogels of both kinds were stable in simulated gastric fluid, but were prone to swelling and degradation in the presence or absence of enzyme dextranase in simulated intestinal fluid. The release profiles of nanoparticles could be tuned from 5 hr to 24 hr periods of time with more than 85% of the nanoparticle released in the simulated intestinal fluid. The release of PAX NPs was completed with longer time periods (45 hr-120 hr). Two possible release mechanisms were discussed for Dex-MA and Dex-GMA-co-AA hydrogels respectively: degradation controlled, and diffusion controlled. These biodegradable hydrogels, which can release nanoparticles depending on pH changes, together with the biocompatible and targeted nanoparticles, may be suitable as a potential colon targeting system for oral delivery of drug nanoparticles.

博士<br>高雄醫學大學<br>藥學研究所博士班<br>92<br>Epidermal growth factor (EGF) is a polypeptide of 53 amino acid residues with a molecular weight of 6216. Based on it has many bioactivities, it has developed to accelerate wound healing as clinical pharmaceutical formulations. Although several approaches were reported the related studies about the stability of EGF in different solutions and body fluids and in progress to develop pharmaceutical formulations that allow administration of EGF effectively. Until present, there still had no appropriately optimized pharmaceutical formulations due to the instability of EGF and the used materials inappropriately. Herein we enclosed the stability of EGF completely including the physical, chemical and enzymatic stability of EGF, and choose the best prepared condition to design the optimize formulations of EGF, including liposome and collagen sponge, with topical controlled drug release system for bringing the EGF into full play. In these studies, we successfully developed the FTIR micro- spectroscopy to analyze the stability of EGF in physical stability and choose the conditions for preparation. For examples, the temperature of preparation controlled below 40oC, the pHs controlled to natural and 2M sodium chloride added to EGF solution could increase the stability of EGF. It would decrease the stability of EGF in the solutions containing structure perturbants and iodide ion. In chemical stability of EGF, we discussed the reactive kinetics of EGF in different pHs and temperatures. In enzymatic stability of EGF, we found the aminopeptidase inhibitor, Bestatin, could avoid EGF to be broken from enzyme. In addition, pig skins were the most closed to human skin and could be used to modify the burned model as the replaced animal models. It could induce the acid proteases, capthesin B, and increase the endocrine EGF of body after the skin burned. Then, due to the enzyme increased, EGF would be rapidly depredated. In the design of EGF into topical controlled release system, the encapsulation efficacy of EGF-liposome formulation was about 25-75% under the low content of cholesterol and the negative charge of phospholipids encapsulated. And the particles size could be controlled between 0.11~0.21 �慆. Besides, the EGF-collagen sponge modified with the cross-linkage reagent, glutaraldehyde, could be chosen by the patient’s requirement depended on the different size of wound and the released rate of EGF needed. And it contained 3D structure, nice water uptake, stronger mechanical strength, and cell stimulation ability. Therefore, we successfully developed the formulation of EGF with topical controlled release properties from the animal study. It could carry EGF sufficiently into full play and increase the wound healing.

碩士<br>臺北醫學大學<br>藥學研究所<br>96<br>The objective of this study was to (1) find a possible correlation between mechanical characteristics determined by DMA and floating properties measured on coated pellets from studies (2) develop and evaluate ideal floating drug delivery systems (FDDS) consisting of a drug-containing core pellet with a polymeric coating. The mechanical properties (strength and elongation) of acrylic (Eudragit® RS 30D, RL 30D or NE 30D) and cellulosic (Surelease®、EC) polymers with different plasticizer type were studied by the dynamic mechanical analyzer in the dry and wet state. Films prepared from Surelease® and EC resulted in brittle films when compared to the acrylic films. Films of Eudragit® NE 30D were very flexible in both the dry and wet state. Because the plasticizer leached from the polymeric films during exposure to the aqueous medium, wet Eudragit® RS 30D and RL 30D polymer films plasticized with 15% TEC or DEP result in decreasing elongation. When Eudragit® RL 30D was the polymer coating for the floating system, the pellets had excellent floating ability but the sustained release properties could not be achieved. Besides, Eudragit® RL 30D plasticized with 15% DEP and DBP had better floating ability than TEC. The system using Eudragit® RS 30D as polymeric membranes had sustained release properties. However, the pellets did not float because Eudragit® RS 30D might not be permeable enough for medium to generate sufficient amount of CO2. To solve these problems, a 1:1 ratio of Eudragit® RL 30D and RS 30D plasticized with 15% DEP was used as the polymeric membrane in the floating system. Although the release of losartan from the pellets was still too fast as a result of losartan being freely soluble in water, the FDDS coated with Eudragit® RL 30D combined with RS 30D might have potential use for oral delivery of water insoluble drug. Based on these results, although there are some other factors such as water permeability and the solubility of model drug need to be considered, DMA can be a preliminary screening tool to identify film properties for application as floating systems.

碩士<br>國立臺灣海洋大學<br>生物科技研究所<br>99<br>Research in intelligent drug delivery system is considerably interesting in biomedical fields. The system can be specifically stimulated to perform controlled drug release. In this study, mesoporous bioactive glass (MBG) act as an intelligent drug delivery carrier, modification of the pore outlets of the carrier with photo sensitive coumarin derivative may possess a gate-like block which can be stimulated by different wavelength of UV light to form open and close system. Exposure under UV light > 310 nm wavelength may form cyclobutane dimers through the coumarin derivative and trapping the guest molecules inside the pores. While irradiating the dimerized coumarin modified MBG with shorter wavelength UV light (~ 250 nm) will photo-cleavage the dimmers and regenerate coumarin monomer derivative, letting the guest molecules to release. In addition, doping rare earth element, europium, into the MBG structure allowed the MBG have the ability of photoluminescence, and its emission intensity will change with the cumulative released amount of the guest molecules in the carrier. Therefore, the extent of guest molecule release can be easily tracked and monitored by the change of luminescence. Herein, we use a model amino acid L-tryptophan as the guest molecule to test the modified MBG to present as an intelligent multi-controlled drug delivery system. Apart from the photoluminescent ability, lanthanides also have the characteristic of imitating calcium ion, which can replace some part of calcium ions in bone and activated the osteoblasts to promote bone formation and inhibit bone degradation and absorption. This calcium imitating capability makes lanthanide a potential treatment for bone diseases, and also makes the carrier a better intelligent drug delivery system for the application on bone repair treatments. The structural, morphological, textural and optical properties are well characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption/desorption, and photoluminescence spectra, respectively. The results reveal that the lanthanide doped MBG exhibits the typical ordered characteristics of mesostructure. The system demonstrates great potential in light-sensitive intelligent drug delivery systems and disease therapy fields.

This thesis describes evaluation of a gastric retention device (GRD) developed at Oregon State University. The device was originally fabricated from Xanthan gum and Locust bean gum. A modified gastric retention device containing other additives was developed and investigated in this work. The modified device was evaluated in vitro for swelling and dissolution properties using riboflavin as a model drug. Different shapes and sizes of GRDs were tested in dogs to study the gastric retention potential of these devices. The effect of the device on food emptying from the stomach in dogs was also investigated. Endoscopic studies in dogs also showed that the device swells rapidly and considerably in gastric fluid. The bioavailability of riboflavin from three different size GRDs was determined in six fasted human volunteers and compared to an immediate release formulation. The biostudy indicated that the bioavailability of riboflavin from a large size GRD was more than triple that measured after administration of the immediate release formulation. Deconvolution was used to determine gastric residence time of the different size GRDs. A new colonic delivery system made of acetaminophen loaded beads produced by extrusion and spheronization and coated with different ratios of pectin and ethylcellulose coating solutions in a spray coating apparatus was also developed in this work. Such beads release their drug content in the colon due to susceptibility of pectin in the outer coat to enzymatic action of colonic bacteria. The new delivery system was evaluated in vitro by conducting release studies in different dissolution media to mimic transit times, pH and enzyme conditions in the gastrointestinal tract. The gastrointestinal transit behavior of drug beads was also assessed by conducting gamma-scintigraphic studies in dogs. The bioavailability and pharmacokinetic parameters of acetaminophen from several colonic delivery system formulations were determined in human volunteers and compared to the immediate release commercial product Tylenol®. A selected pectin-ethylcellulose coat formulation in the ratio 1:3 was further evaluated in six volunteers under both fed and fasting conditions and was found to be effective and to provide sustained drug release in the colon over a period of 12 hours.<br>Graduation date: 2003

碩士<br>國立清華大學<br>化學工程學系<br>95<br>A series of biodegradable poly (ester-anhydride), Poly(sebacic anhydride-co-ethylene glycol), was prepared by melt condensation for use in advanced drug delivery applications. Sebacic acid, a hydrophobic monomer, was copolymerized with PEG in order to produce water-insoluble polymers capable of providing continuous drug release kinetics following immersion in an aqueous environment. Poly ethylene glycol(PEG) can reduce particle clearance from bloodstream by macrophages and was a FDA approved polymer. In this paper, we changed various amounts of PEG (15~35% by mass) incorporated into the backbone of the polymers to allow tuning of particle surface properties. The diblock copolymers were synthesized with the molecular weight range of 9,500~14,500 Da without any catalyst. Copolymers of higher molecular weights were obtained by increasing poly (sebacic anhydride) content. The self-assembly of this water-insoluble diblock copolymer formed nanoparticles by solvent displacement method. The mean diameters of micelles were less than 200nm and exhibited low polydispersity index. The degradation of polymeric micelles was studies by measuring the sebacic acid concentration in phosphate buffer. The result showed that a rapid degradation occurred during first 6 hr, followed by a slow degradation. After 5 days, about 70~80% of polymeric micelles core were degraded. The drug encapsulation efficiency and the in vitro drug release kinetics were measured by high-performance liquid chromatography (HPLC). Of all, the entrapment efficiency of taxol-loaded micelles were 10.31~40.51%. The longer hydrophobic chain was, the lower its entrapment efficiency was. The drug release from mPEGPSA nanoparticle was found to be biphasic with an initial burst of 60~70% during the first 2hr, followed by a sustained release with 100% accumulative drug release after 5 days.

博士<br>淡江大學<br>化學工程與材料工程學系博士班<br>97<br>In the fisrt part of this study, emulsifier-free emulsion polymerization of MMA was initiated directly by the Cu2+/HSO3- redox system. Latex particles with negative charge due to the bonded anionic sulfite ion were successfully synthesized after 2 h of reaction at 40 to 60oC. SEM pictures showed an uniform particle size distribution, and the average size decreased from 223 nm to 165 nm by increasing reaction temperature from 40oC to 60oC. The initiation step in polymerization mechanism was proved to be a redox reaction, in which Cu2+ oxidized the bisulfite ion to produce anionic sulfite radical and proton. The produced anionic sulfite radical then initiated polymerization of MMA. Moreover, Cu2+ not only served as one component in the redox initiator system but also a chain transfer agent that terminated growing polymer chains to produce chains with unsaturated end group (PMMA-CR=CH2). For the present system, about 17 % of PMMA-CR=CH2 was produced. The tacticities of PMMA latex prepared at 40~60oC were almost the same, ca. 62~64 % rr, 33~35 % mr, and 3 % mm. These PMMA latexes had almost the same Tg, 125~127oC, regardless of the reaction temperatures and their weight-average molecular weight was in the range between 254,000 and 315,000. PMMA latex was synthesized in an emulsifier-free emulsion polymerization at 60oC using a Cu2+/HSO3- redox initiator system with different concentrations of Cu2+. The experimental results showed that the monomer conversion reached above 90 % for all systems. Zeta potential was all negative due to the bonded bisulfite ion and the magnitude was greater than 30 mV, providing the stability of PMMA emulsion. The morphology of the latex observed by SEM revealed an uniform particle size and the average particle size increased from 181.9 nm to 234.2 nm as the Cu2+ ion concentration increased from 2.0 mM to 6.0 mM in 1 M of MMA solution. Thermal degradation behavior of synthesized PMMA was studied by TGA, in which a two-stage degradation behavior was observed. These two stages were found to be caused by the degradation of unsaturated end group (PMMA-CR=CH2) and saturated end group (PMMA-H), respectively. In addition, the higher the concentration of Cu2+ ion, the more the proportion of PMMA-CR=CH2 in final product, and in turn giving more weight loss in the first-stage degradation. The copper ion not only acted as a role in the redox initiation, but also as a chain transfer agent to terminate growing polymer chains thus producing PMMA-CR=CH2. The apparent activation energies of the first stage (Ea1) and second stage (Ea2) were calculated by Ozawa’s method as well as Boswell’s method. The results showed that the apparent activation energies of PMMA-CR=CH2 were in the range between 123.6 kJ/mol and 134.8 kJ/mole, and those of PMMA-H were in the range between 156.4 kJ/mol and 213.4 kJ/mole. In the second part this study, Chitosan-PNIPAAm-PEGMA (CS-PN-PEG) microgel copolymers were synthesized with biocompatible Chitosan (CS), thermal-responsive N-isopropylacrylamide (NIPAAm), and non-immunogenic Poly(ethylene glycol) metharcylate (PEGMA) by using ammonium persulfate (APS) as the initiator. In the batch reaction system, two-stage transition behaviors of CS-PN-PEG microgel copolymer were observed because the reaction product was composed of CS-PN-PEG and CS-PN copolymers due to the different monomer reactivity. In the continuous-feeding reaction system, one stage transition behavior of CS-PN-PEG microgel copolymer was observed. At pH4, the LCST values were shifted to higher temperatures from 33.0oC to 39.7oC with increasing the addition of hydrophilic PEGMA monomer. CS-PN-PEG microgel copolymer was immediately shrunk as the temperature reached to LCST due to the well-hydrophilic chitosan chains with excellent mobility tended to disentanglement at acidic condition. At pH7, the LCST values were shifted to higher temperatures from 35.7oC to 45oC with increasing hydrophilic PEGMA monomer. One stage transition behavior of CS-PN-PEG microgel copolymer exhibited slightly delay at neutrality due to the worse chain mobility on chitosan. The average particle size was in the range between 290 nm and 450 nm by using light scattering method. In addition, gold nanorods (AuR) were prepared by a seed-mediated growth approach. The longitudinal surface of plasmon resoncance (SPL) of AuR exhibited red-shifts with increasing the addition of silver ion. As Ag+/Au3+G ratio reached to 0.35, AuR had the maximum yield in which the SPL, max increased to 779 nm. AuR (SPL, max=806 nm and Abs. =2) was obtained by controlling the aging time. Moreover, CS/AuR/CS-PN-PEG10 complex carrier was obtained by using water in oil (W/O) method. After encapsulation of diclofenac sodium (DS), the loading was 0.669 % and encapsulation efficiency was 78 %. When CS/AuR/CS-PN-PEG10 complex carrier was irradiated by near IR light, they transformed the light into heat and thus raised temperature of the carrier. Subsequently, the thermal-responsive component undergoes phase transition causing volume shrinkage to squeeze out DS drug. After 24 hours, drug release amount reached 58.9%.

碩士<br>嘉南藥理科技大學<br>生物科技系暨研究所<br>96<br>The purpose of this study was the preparation and characterization of drug containing polymer gel beads. Natural and biocompatible chitosan was dissolved with drug in 5 wt% acetic acid solution. Different chitosan gel beads were obtained by polyelectrolyte complexation with sodium salt of carboxymethyl cellulose and tripolyphosphate. The effect of drug entrap ratio, gel particle size, morphology and physical properties on drug released behavior were investigated. The results showed that the drug can sustain 16 hrs and its release rate was consistent with T. Higuchi model.

碩士<br>國立交通大學<br>材料科學與工程學系奈米科技碩博士班<br>104<br>Recently, due to the high mortality caused by cancer, development of carriers for cancer therapy had engaged a lot of attentions for many researchers. Among these investigations, superparamagnetic iron oxide nanoparticles (SPIONs) and their derivatives have been widely investigated in numerous medical applications. In this study, we have successfully synthesized superparamagnetic iron oxide nanoparticles by co-precipitation method, and then gold nanoshell was coated by reduction method. This Fe3O4@Au core-shell structure served as a substrate for further applications in multifunctional drug delivery system with both magnetic properties derived from Fe3O4 and optical properties derived from gold nanoshell surface. Because of the specific surface characteristic of gold nanoshell, we could modify special-designed sequence of DNA with thiol bonding. By means of the sequence including not only an aptamer which had been demonstrated with specific binding ability, but also CG-rich fragments which carried doxorubicin (DOX) as anticancer drug, both the drug loading and specific targeting could be achieved . By triggered with high frequency magnetic field (HFMF), high release percentage could be achieved efficiently in relatively short period of time. Besides, by adjusting the concentration of reduction agent, we had synthesized Fe3O4@Au with different size distribution. The thickness of gold nanoshell would influence of Fe3O4@Au in magnetic, surface area and other physical properties, which also affected the performance for cancer therapy. First, temperature increment caused by high frequency magnetic field would decrease with the increasing thickness of nanoshell due to the shield effects. Next, larger surface area, which leads to higher DNA binding concentration, relatively carry more DOX molecules. This phenomenon further results in the difference of chemotherapeutic ability. At last, cytotoxicity of our dsDNA-conjugated Fe3O4@Au drug carrier was investigated under concern for future applications. No obvious apoptosis by in vitro cell viability test exhibited good biocompatibility of our carriers. At the same time, our drug-capsulated carriers had been proved to eliminate cancer cell under HFMF. With both effects of chemotherapy and hyperthermia, lower minimum amount of drug that has to be used was predicted, which means side effects could be reduced effectively. In conclusion, we have successfully built a release- controlled drug delivery system based on a special-designed drug carrier under HFMF treatment, in which chemotherapy, hyperthermia and specific targeting were all integrated.. Moreover, the study of size effect demonstrated that sizes of these particles act as a controllable and efficient factor for drug delivery behavior and the system tend to be more completed consequently.

碩士<br>國立清華大學<br>奈米工程與微系統研究所<br>99<br>Transdermal delivery is an attractive alternative of drug delivery. Comparing to the conventional drug delivery techniques using pills or injections, this approach avoids degradation in the gastrointestinal tract and the pain of injections. But it is limited by the low permeability of skin because the stratum corneum (SC) in the upper skin (10-20 μm) is the main barrier. Hence, we used the Bio-MEMS technique to make microneedle array patch to inset into skin. This microneelde array patch could easily cross the SC but not so long that reach the deeper tissue and simulate nerves to developed a convenient, pain-free, and high efficient transdermal delivery patch. In this study, we present a novel approach to transdermal drug delivery that is two-step controlled-release system based on the skin cancer application. We used fluorescent dyes as model drugs to simulate the slow effect of anti-cancer drug and short half-time of anesthesia and vasoconstrictor. First, we used backside exposure technology of UV-lithography to fabricate microneedle array mold and bio-available PVP polymer with 1st model drug as the microneedle array materal. Second, we used double emulsion technology to fabricate pH-sensitive PLGA HMS (Hollow Micro-Spheres) with 2nd model drug. Sequentially, we combined these two techniques to fabricate the two-step controlled-release microneedle patch. This microneedle patch was shown two-step releasing profiles in vitro, the insertion capability ex vivo, and the transcutaneous delivery in vivo. As a consequence, we conclude that the two-step controlled-release can release two drugs with a time difference to the skin.

碩士<br>國立臺北教育大學<br>自然科學教育學系<br>107<br>Nanotechnology gets more and more popular in many biomedical applications. Peptide self-assembled nanodrug is one of the most promising applications among them because its enhanced permeability and retention effect (EPR). Peptide-originated structures have tremendous advantages including its intrinsic low toxicity, high translation values, excellent biocompability and biodegradability, high tissue permeability, nonimmunogenicity,tunable bioactivity and stimuli responsive at tumor areas. Herein, we report the development of a high drug loading, polypeptide assembled drug delivery nanostructure which can split into smaller carriers responded towards the acidic environment at disease sites. The PLLD nanoparticles is formed by the antitumor drug Doxorubicin and pyrene modified polypeptide (PLL) which was first time applied to be a building block of drug delivery system via non-covalent interaction. The most promising feature of this carrier is the therapeutic itself is considered as one of the building blocks to composite the carriers instead of the conventional one to be encapsulated in the delivery system. The advantages of coassembly the peptide with drugs are the structural stable of carrier, enhanced drug loading efficiency, and fully interpenetrated interacting process of both components in a controlled and modulated way. The PLLD nanocarriers were inspected as uniform spheres under Transmission Electron Microscope (TEM) and found the unique drug release pathway which results in strong cytotoxicity towards human colon cancer cells and great tumour suppression capability in xenograft animal experiments.