Log in

Relevant bibliographies by topics / Sustained and controlled release

Contents

Journal articles
Dissertations / Theses
Books
Book chapters
Conference papers
Reports

Academic literature on the topic 'Sustained and controlled release'

Author: Grafiati

Published: 5 June 2025

Last updated: 24 June 2025

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Sustained and controlled release.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Journal articles on the topic "Sustained and controlled release"

1

Gauthier, Serge, and Donna Amyot. "Sustained Release Antiparkinson Agents: Controlled Release Levodopa." Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 19, S1 (1992): 153–55. http://dx.doi.org/10.1017/s0317167100041548.

Full text

Abstract:

ABSTRACT:The rationale for sustained release oral levodopa preparations is to deliver levodopa in the areas of maximal intestinal absorption in a slow and predictable way, leading to stable plasma levodopa levels and brain dopamine levels, therefore resulting in a lengthened duration of action. Sinemet CR is the prototype of such preparations, with demonstrated efficacy in decreasing periods of akinesia in parkinsonian patients with mild to moderate motor fluctuations. Total doses of levodopa are raised 10 to 30% because of the lowered bioavailability; diphasic dyskinesias may increase at the end of the day. Tolerance is good in de novo patients and studies are in progress to establish if early treatment with Sinemet CR delays the onset or attenuates the severity of motor fluctuations as compared to standard Sinemet.

APA, Harvard, Vancouver, ISO, and other styles

2

Kumar, Deepak, ,. Archana, and Abadhesh Kumar Niranjan. "A Comprehensive Review on Sustained Release Matrix Drug Delivery System." Journal of Drug Delivery and Therapeutics 12, no. 4-S (2022): 249–53. http://dx.doi.org/10.22270/jddt.v12i4-s.5540.

Full text

Abstract:

Formulations for sustained medication release are very useful in the treatment of chronic disorders. The oral route has selected matrix tablets as the most likely type of prolonged drug release. In order to generate therapeutic activity for a protracted duration, matrix tablets maintain a stable plasma drug concentration and sustain the rate of release of the drug throughout time. In preparations with a short half-life and high dosage frequency, extended-release is crucial. The matrix regulates how quickly the medication is released. Retardants such polyglycolic acid, polymethyl methacrylate, and hydroxypropyl methylcellulose (HPMC) are used. The retardant's matrix core contains the medication. The matrices employed can be mineral-based, hydrophobic, or biodegradable. Drug release is regulated in matrix tablets that can be made using wet granulation or direct compression techniques by the use of various kinds of polymers. Drug release from matrix tablets is controlled by both diffusion- and dissolution-controlled process. As a result, matrix tablets increase therapeutic efficacy while reducing the frequency of drug administration and increasing patient compliance. Keywords: Sustained release, Matrix Tablets, HPMC, Retardants, Biodegradable

APA, Harvard, Vancouver, ISO, and other styles

3

Kalyani Shelar, Gauri Mahajan, Nikita Pagare, Prachiti Sahane, and Sakshi Bhosale. "Review on Sustained Release Tablet." International Journal of Scientific Research in Science and Technology 11, no. 6 (2024): 698–708. https://doi.org/10.32628/ijsrst241161126.

Full text

Abstract:

This review highlights the advantages of SR formulations, including reduced side effects, enhanced drug utilization, improved treatment efficacy, and better patient compliance. Key considerations for developing sustained release tablet involve the drug's physicochemical properties and biological factors, such as absorption and metabolism. Various formulation strategies, including diffusion-controlled, dissolution-controlled, and osmotic systems, are discussed alongside essential evaluation parameters like density, hardness, and in-vitro drug release profiles. The outlook for sustained release tablets is bright , as their growing use in the pharmaceutical industry focuses on enhancing therapeutic effectiveness. Overall, sustained release tablet formulations represent a significant advancement in modern pharmacotherapy, enhancing efficacy and patient adherence to treatment regimens.

APA, Harvard, Vancouver, ISO, and other styles

4

Addanki, Anusha, Ponnekanti Krishnaphanisri, Tiwari Ramanuj, Swapna L., Mabrur Hussain Md, and Siddhardha A. "A review of medicines with sustained release." World Journal of Biology Pharmacy and Health Sciences 13, no. 3 (2023): 221–33. https://doi.org/10.5281/zenodo.8036007.

Full text

Abstract:

Sustained-release matrix tablets allow for continuous drug release while also optimizing a drug's biologic, pharmacokinetic, and pharmacodynamic properties for maximum therapeutic efficacy. The matrix regulates the rate at which the drug is released. Because it facilitates prolonged release, the major excipient in the formulation is a release retardant. The technology may promote patient compliance and efficiently treat chronic illnesses by decreasing the overall dosage and dosing schedule. The drug is supplied in this system via diffusion- and dissolution-controlled methods. The primary goal of this analysis is to provide comprehensive information on the sustained release system and to discuss the many selection criteria for medicines used in medication administration system

APA, Harvard, Vancouver, ISO, and other styles

5

Addanki Anusha, Krishnaphanisri Ponnekanti, Ramanuj Tiwari, L. Swapna, Md Mabrur Hussain, and A Siddhardha. "A review of medicines with sustained release." World Journal of Biology Pharmacy and Health Sciences 13, no. 3 (2023): 221–33. http://dx.doi.org/10.30574/wjbphs.2023.13.3.0141.

Full text

Abstract:

Sustained-release matrix tablets allow for continuous drug release while also optimizing a drug's biologic, pharmacokinetic, and pharmacodynamic properties for maximum therapeutic efficacy. The matrix regulates the rate at which the drug is released. Because it facilitates prolonged release, the major excipient in the formulation is a release retardant. The technology may promote patient compliance and efficiently treat chronic illnesses by decreasing the overall dosage and dosing schedule. The drug is supplied in this system via diffusion- and dissolution-controlled methods. The primary goal of this analysis is to provide comprehensive information on the sustained release system and to discuss the many selection criteria for medicines used in medication administration system

APA, Harvard, Vancouver, ISO, and other styles

6

KATO, Yasutomi, Hisakazu SUNADA, Yorinobu YONEZAWA, and Ryuzo ISHINO. "Sustained Release Mechanisms of Wax Matrix System for Controlled Release." CHEMICAL & PHARMACEUTICAL BULLETIN 42, no. 8 (1994): 1646–50. http://dx.doi.org/10.1248/cpb.42.1646.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Khoder, Mouhamad, Henry Gbormoi, Ali Ryan, Ayman Karam, and Raid Alany. "Potential Use of the Maillard Reaction for Pharmaceutical Applications: Gastric and Intestinal Controlled Release Alginate-Albumin Beads." Pharmaceutics 11, no. 2 (2019): 83. http://dx.doi.org/10.3390/pharmaceutics11020083.

Full text

Abstract:

In this study, bovine serum albumin (BSA) and alginate (ALG) conjugates were synthesized by the Maillard reaction in order to evaluate their potential to develop controlled release drug delivery systems. The progress of the Maillard reaction was evidenced using ultraviolet (UV) absorbance, determination of BSA remaining free amino groups, and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). BSA-ALG conjugates possessed enhanced and tunable viscosity, foamability and foam stability. Foam generated from BSA-ALG conjugate solution was used to prepare floating gastroretentive calcium ALG beads. Unlike traditional ALG beads, BSA-ALG foam beads were able to float and sustain the ciprofloxacin (CIP) release in gastric medium. Interestingly, intestinal beads made of ALG, BSA-ALG physical mixture and BSA-ALG conjugate resulted in different release rates and orders of indomethacin (IND) in simulated intestinal fluids; while beads based on a physical mixture of BSA-ALG resulted in a first order sustained release profile, both systems based on ALG and BSA-ALG conjugate displayed zero order sustained release profiles with IND being released at a slower rate from the conjugate beads.

APA, Harvard, Vancouver, ISO, and other styles

8

Bayer, Ilker S. "Controlled Drug Release from Nanoengineered Polysaccharides." Pharmaceutics 15, no. 5 (2023): 1364. http://dx.doi.org/10.3390/pharmaceutics15051364.

Full text

Abstract:

Polysaccharides are naturally occurring complex molecules with exceptional physicochemical properties and bioactivities. They originate from plant, animal, and microbial-based resources and processes and can be chemically modified. The biocompatibility and biodegradability of polysaccharides enable their increased use in nanoscale synthesis and engineering for drug encapsulation and release. This review focuses on sustained drug release studies from nanoscale polysaccharides in the fields of nanotechnology and biomedical sciences. Particular emphasis is placed on drug release kinetics and relevant mathematical models. An effective release model can be used to envision the behavior of specific nanoscale polysaccharide matrices and reduce impending experimental trial and error, saving time and resources. A robust model can also assist in translating from in vitro to in vivo experiments. The main aim of this review is to demonstrate that any study that establishes sustained release from nanoscale polysaccharide matrices should be accompanied by a detailed analysis of drug release kinetics by modeling since sustained release from polysaccharides not only involves diffusion and degradation but also surface erosion, complicated swelling dynamics, crosslinking, and drug-polymer interactions. As such, in the first part, we discuss the classification and role of polysaccharides in various applications and later elaborate on the specific pharmaceutical processes of polysaccharides in ionic gelling, stabilization, cross-linking, grafting, and encapsulation of drugs. We also document several drug release models applied to nanoscale hydrogels, nanofibers, and nanoparticles of polysaccharides and conclude that, at times, more than one model can accurately describe the sustained release profiles, indicating the existence of release mechanisms running in parallel. Finally, we conclude with the future opportunities and advanced applications of nanoengineered polysaccharides and their theranostic aptitudes for future clinical applications.

APA, Harvard, Vancouver, ISO, and other styles

9

Sadhu, Venkateswara Rao, Priyanka Bopparaju, and Padmalatha Kantamneni. "Bilayer tablet technology: A novel approach." GSC Biological and Pharmaceutical Sciences 7, no. 2 (2019): 022–28. https://doi.org/10.5281/zenodo.4286145.

Full text

Abstract:

Bilayer tablet is new era for the successful development of controlled release formulation along with various features to provide a way of successful drug delivery system. Controlled release dosage forms have been extensively used to improve therapy with several important drugs. Use of bilayer tablet is a very different aspect for anti-inflammatory and analgesic. Bilayer tablet is suitable for sequential release of two drugs in combination, separate two incompatible substances and also for sustained release tablet in which one Layer is immediate release as initial dose and second layer is maintenance dose. Bilayer tablet is improved beneficial technology to overcome the shortcoming of the single layered tablet. This article provides an overview of the bilayer tablet technology, highlighting the main benefits of this type of oral dosage forms while providing a description of current challenges and advances toward improving manufacturing practices and product quality.

APA, Harvard, Vancouver, ISO, and other styles

10

CHRYSANT, S., and M. COHEN. "Sustained blood pressure control with controlled-release isradipine." American Journal of Hypertension 8, no. 1 (1995): 87–89. http://dx.doi.org/10.1016/0895-7061(94)00158-8.

Full text

APA, Harvard, Vancouver, ISO, and other styles

More sources

Dissertations / Theses on the topic "Sustained and controlled release"

1

Rodriguez, Lidia Betsabe. "Controlled Release System for Localized and Sustained Drug Delivery Applications." University of Toledo / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1365107103.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Khamanga, Sandile Maswazi Malungelo. "Formulation and assessment of verapamil sustained release tablets." Thesis, Rhodes University, 2005. http://hdl.handle.net/10962/d1018236.

Full text

Abstract:

The oral route of drug administration is most extensively used due to the obvious ease of administration. Verapamil hydrochloride is a WHO listed phenylalkylarnine, L-type calcium channel antagonist that is mainly indicated for cardiovascular disorders such as angina pectoris, supraventricular tachycardia and hypertension. Due to its relatively short half-life of approximately 4.0 hours, the formulation of a sustained-release dosage form is useful to improve patient compliance and to achieve predictable and optimized therapeutic plasma concentrations. Direct compression and wet granulation were initially used as methods for tablet manufacture. The direct compression method of manufacture produced tablets that exhibited formulation and manufacturing difficulties. Mini-tablets containing veraparnil hydrochloride were then prepared by wet granulation using Surelease® E-7-19010.and Eudragit® NE 30D as the granulating agents after which the granules were incorporated with an hydrophilic matrix material, Carbopol® 974P NF. Granule and powder blends were evaluated using the angle of repose, loose and tapped bulk density, Can's compressibility index, Hausner's ratio and drug content. Granules with good flow properties and satisfactory compressibility were used for further studies. Tablets were subjected to thickness, diameter and weight variation tests, crushing strength, tensile strength, friability and content uniformity studies. Tablets that showed acceptable pharmaco-technical properties were selected for further analysis. Drug content uniformity and dissolution release rates were determined using a validated isocratic HPLC method. Initially, USP apparatus 1 and 3 dissolution apparatus were used to determine in-vitro drug release rates from the formulations over a 22-hour period. USP apparatus 3 was finally selected as it offers the advantages of mimicking, in part, the changes in the physicochemical environment experienced by products in the gastro-intestinal tract. Differences in release rates between the test formulations and a commercially available product, Isoptin® SR were observed at different pH's using USP apparatus 1. The release of veraparnil hydrochloride from matrix tablets was pH dependent and was markedly reduced at higher pH values. This may be due, in part, to the poor solubility of veraparnil hydrochloride at these pH values and also the possible interaction of verapamil hydrochloride with anionic polymers used in these formulations. Swelling and erosion behaviour of the tablets were evaluated and differences in behaviour were observed which may be attributed to the physico-chemical characteristics of the polymers used in this study. In-vitro dissolution profiles were characterized by the difference (j1) and similarity factor (j2) and also by a new similarity factor, Sct. In addition, the mechanism of drug release from these dosage forms was mainly evaluated using the Korsmeyer-Peppas model and the kinetics of drug release assessed using other models, including Zero order, First order, Higuchi, HixsonCrowell, Weibull and the Baker-Lonsdale model. Dissolution kinetics were best described by application of the Weibull model, and the Korsmeyer-Peppas model. The release exponent, n, confirmed that drug release from these dosage forms was due to the mixed effects of diffusion and swelling and therefore, anomalous release kinetics are predominant. In conclusion, two test batches were found to be comparable to the reference product Isoptin® SR with respect to their in-vitro release profiles.

APA, Harvard, Vancouver, ISO, and other styles

3

McLellan, Bradley John. "Development of an Intraruminal Controlled-Release Device." The University of Waikato, 2007. http://hdl.handle.net/10289/2527.

Full text

Abstract:

Slow-release devices retained in the rumen, are a simple method for continuous administration of bioactives to ruminant animals. To satisfy regulatory requirements and avoid waste of bioactive due to under- or over-dosing, it is advantageous to have a constant and predictable release rate. Existing intraruminal controlled-release technologies cannot easily be adapted for different bioactives or rates of release and can be influenced by the variable physiological environment in the rumen. Some existing commercial products use the pressure generated by a hydrogen gas-producing cell to extrude fluids from a syringe-like device. This technology may provide advantages for ruminal controlled-release as the gas production rate is unaffected by environment in the rumen and can be easily adjusted using electrical resistance applied to the gas cell. This technology was adapted for use in the rumen in these studies. Initial experiments identified the need for greater understanding of the rate that hydrogen is produced by the gas cell and the rate that gas diffuses through the barrel walls. Gas production rate was found to be inversely proportional to the resistance applied to the gas-producing cell. Factors affecting gas diffusion rate from the device were studied and a polymer was identified that reduced hydrogen diffusion to 5% of that for the initial components used. A relationship was developed to predict the release profile of a device. Controlled-release devices were constructed from selected materials. They released blank formulation at in vitro at a constant rate, which was within experimental variation of predicted values. Release rates from the devices used in vivo were slightly higher than predicted. The presence of rumen gases inside in vivo devices suggested that the difference may be due to inward diffusion of these gases; these may be eliminated by further study of barrel materials. Recommendations on the redesign of this technology for use as a generic intraruminal delivery system are given.

APA, Harvard, Vancouver, ISO, and other styles

4

Sachikonye, Tinotenda Chipo Victoria. "Development and assessment of minocycline sustained release capsule formulations." Thesis, Rhodes University, 2010. http://hdl.handle.net/10962/d1013127.

Full text

Abstract:

The use of minocycline for the treatment of a broad range of systemic infections and for severe acne has been associated with vestibular side effects. The severity of side effects may lead to poor adherence to therapy by patients. The use of sustained release formulations of minocycline that display slow dissolution of minocycline following administration may be beneficial in reducing the incidence and severity of side effects. Therefore, sustained release capsule dosage forms containing 100 mg minocycline (base) were manufactured and assessed for use as sustained release oral dosage forms of minocycline. Minocycline sustained release capsules were manufactured based on matrix technologies using hydroxypropylmethyl cellulose (HPMC) and Compritol® as release retarding polymers. The rate and extent of minocycline release from the capsules was evaluated using USP Apparatus 1 and samples were analysed using a validated High Performance Liquid Chromatographic (HPLC) method with ultraviolet (UV) detection. Differences in the rate and extent of minocycline release from formulations manufactured using HPMC or Compritol® were influenced by the concentration of polymer used in the formulations. The rate and extent of minocycline release was faster and greater when low concentrations of polymer were used in formulations. The effect of different excipients on the release pattern(s) of minocycline and particularly their potential to optimise minocycline release from experimental formulations was investigated. The use of diluents such as lactose and microcrystalline cellulose (MCC) revealed that lactose facilitated minocycline release when HPMC was used as the polymer matrix. In contrast, the use of lactose as diluent resulted in slower release of minocycline from Compritol® based formulations. The addition of sodium starch glycolate to HPMC based formulations resulted in slower release of minocycline than when no sodium starch glycolate was used. Compritol® based formulations were observed to release minocycline faster following addition of sodium starch glycolate and Poloxamer 188 to experimental formulations. In vitro dissolution profiles were compared to a target or reference profile using the difference and similarity factors, ƒ1 and ƒ2 , and a one way analysis of variance (ANOVA). In addition, the mechanism of minocycline release was elucidated following fitting of dissolution data to the Korsmeyer-Peppas, Higuchi and Zero order models. Minocycline release kinetics were best described by the Korsmeyer-Peppas model and the values of the release exponent, n (italics), revealed that drug release was a result of the combined effects of minocycline diffusion through matrices and erosion of the matrices. These in vitro dissolution profiles were better fit to the Higuchi model than to the Zero order model. Two formulations that displayed a fit to the Zero order model were identified for further studies as potential dosage forms for sustained release minocycline.

APA, Harvard, Vancouver, ISO, and other styles

5

Kao, Chen-Yu. "Developing a Minimally Invasive Sustained Release System for Glioma Therapy." Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19757.

Full text

Abstract:

Malignant brain tumor is one of the most lethal forms of cancers. In the United States alone, approximately 20,500 new cases of primary malignant brain and central nervous system tumors are expected to be diagnosed in 2007 with 12,740 deaths estimated. Treatment of malignant brain tumor remains a major challenge despite recent advance in surgery and other adjuvant therapies, such as chemotherapy. The failure of potential effective chemotherapeutics for brain tumor treatment is usually not due to the lack of potency of the drug, but rather can be attributed to lack of therapeutic strategies capable of overcoming blood brain barrier for effective delivery of drug to the brain tumor. In this thesis, we developed a minimally invasive sustained release system for glioma therapy. The present study was initiated in an effort to incorporated Doxorubicin (DOX) loaded PLGA particle into an agarose gel, which can provide a continuous release of DOX locally to the tumor site. DOX, a toposiomearase II inhibitor, is not currently used clinically for brain tumor treatment because when delivered systemically it does not cross BBB. Our hydrogel particle system can overcome this shortcoming of DOX. The results from this study demonstrate that the DOX/PLGA particle gel system can maintain the bioactivity of DOX and sustained release DOX for at least 15 day in vitro. The result of in vivo study showed the DOX/PLGA particle gel treated group had significantly extend the medium survival of 9L glioma bearing rat from 21 days to 29 days. Therefore, the success experience of this local and sustained delivery device might benefit the development of future glioma therapy strategy.

APA, Harvard, Vancouver, ISO, and other styles

6

Yeh, Hsi-wei. "Investigation of Polymeric Composites for Controlled Drug Release." VCU Scholars Compass, 2017. http://scholarscompass.vcu.edu/etd/4971.

Full text

Abstract:

The Electrospray (ES) technique is a promising particle generation method for drug delivery due to its capabilities of producing monodisperse PLGA composite particles with unique configurations and high drug encapsulation efficiency. In the dissertation work, the coaxial dual capillary ES was used to generate drug-loaded core-shell PLGA particles to study the effects of particle filling materials, drug loading locations and particle shell thicknesses on the resultant in vitro release behaviors of the hydrophilic and/ or hydrophobic model drugs. Through release profile characterization of drug-loaded PLGA particles (particle size: 400 nm and 1 μm), it was confirmed that the co-encapsulation of Budesonide (BUD, the hydrophobic small-molecule model drug) and Theophylline (THY, the hydrophilic small-molecule model drug) in the particle cores is the most effective drug loading strategy for extended release of the fixed combined BUD and THY. Particles composed of PLGA fillers with lower molecular weights and with greater shell layer thicknesses could release THY in a well controlled fashion. On the other hand, a slower release rate of Bovine Serum Albumin (BSA, the protein model drug) from PLGA particles with greater shell thickness was also observed. Sequential release of BSA and Paclitaxel (PTX, the hydrophobic small-molecule anti-cancer model drug) was achieved by the 400-nm PLGA (Mw: 7,000-17,000 g/mol, LA/GA: 50/50) particles with potential biopharmaceutical applications in cancer therapy.

APA, Harvard, Vancouver, ISO, and other styles

7

Mohl, Silke. "The Development of a Sustained and Controlled Release Device for Pharmaceutical Proteins based on Lipid Implants." Diss., lmu, 2004. http://nbn-resolving.de/urn:nbn:de:bvb:19-30092.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Patel, Fathima. "The development and assessment of a generic carbamazepine sustained release dosage form." Thesis, Rhodes University, 2006. http://eprints.ru.ac.za/1339/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Wang, Qing. "STRATEGIES FOR SUSTAINED RELEASE OF SMALL HYDROPHILIC DRUGS FROM HYDROGEL BASED MATRICES." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1515164088562922.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Marquette, Sarah. "Stabilization and development of sustained-release formulations of protein/antibody for subcutaneous delivery." Doctoral thesis, Universite Libre de Bruxelles, 2014. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209251.

Full text

Abstract:

ABSTRACT<p><p>This project aimed at developing a drug delivery system (DDS) able to enhance the stability and<p>residence time in vivo of antibodies (Abs). The system will deliver drug by the subcutaneous<p>route (SC), while ensuring accurate control of the drug release and the resulting plasmatic level. This technology platform will allow to reduce frequency of injection, potentially decrease side effects and maintain high concentration of Abs which will improve life of patient having chronic disease such as autoimmune and inflammatory disease. Biodegradable synthetic polymer-based formulations (polylactide-co-glycolide (PLGA)) were selected as carriers for encapsulated Abs. This was because they offer good protection for the Abs and allow sustained release of the Abs for a controlled period of time. After the evaluation of different encapsulation methods such as the water-oil-in-water (w/o/w) and the solid-in-oil-inwater<p>(s/o/w) processes, the encapsulation of the Ab in solid state (s/o/w) appeared to be more appropriate for producing Ab-loaded PLGA microspheres (MS). It allowed us to maintain the<p>Ab in a monomeric conformation and to avoid the formation of unsoluble aggregates mainly present at the water/oil interface. The first part of the project was the optimization of both the method for producing the Ab solid particles (spray-drying process) and the encapsulation of these Ab solid particles into the polymeric MS (s/o/w process) by design of experiment (DoE). These optimizations were carried out using a bovine polyclonal immunoglobulin G (IgG) as model molecule. In further optimization of the spray-drying process by (DoE), aqueous Ab solutions were spray-dried using a mini Spray-Dryer assembly with a 0.7 mm spray nozzle. In accordance with the particle size (d(0.5) ~5 μm), the stability (no loss of monomer measured by<p>size exclusion chromatography (SEC) and the yield of the spray-drying process (> 60 % w/w), the process parameters were set of follow: 3 mL/min as liquid feed flow rate, 130°C /75°C as inlet temperature (inlet T°) / outlet temperature (outlet T°), 800 L/h as atomization flow rate and<p>30 m3/h as drying air flow rate. For the s/o/w, the methylene chloride (MC) commonly used for<p>an encapsulation process was replaced by ethyl acetate (EtAc), which was considered as a more<p>suitable organic solvent in terms of both environmental and human safety. The effects of several processes and formulation factors were evaluated on IgG:PLGA MS properties such as: particle size distribution, drug loading, IgG stability, and encapsulation efficiency (EE%). Several formulations and processing parameters were also statistically identified as critical to get reproducible process (e.g. the PLGA concentration, the volume of the external phase, the emulsification rate, and the quantity of IgG microparticles). The optimized encapsulation<p>method of the IgG has shown a drug loading of up to 6 % (w/w) and an encapsulation efficiency<p>of up to 60 % (w/w) while preserving the integrity of the encapsulated antibody. The produced MS were characterized by a d(0.9) lower than 110 μm and showed burst effect lower than 50 %(w/w). In the second part of the project, the optimized spray-drying and s/o/w processes<p>developed with the IgG were applied to a humanized anti-tumor necrosis factor (TNF) alpha<p>MAb to confirm the preservation of the MAb activity during these processes. The selected s/o/w method allowed us to produce MAb-loaded PLGA MS with an appropriate release profile up to 6 weeks and MAb stability. In order to maintain the Abs’ activity, both during encapsulation and<p>dissolution, the addition of a stabilizer such as trehalose appeared to be crucial, as did the<p>selection of the PLGA. It was demonstrated that the use of a PLGA characterized by a 75:25<p>lactide:glycolide (e.g. Resomer ® RG755S) ratio decreased the formation of low molecular weight species during dissolution, which led to preserve Abs activity through its release from the<p>delivery system. Furthermore, the release profile was adjusted according to the type of polymer<p>and its concentration. E.g. 10 % w/v RG755S allowed Ab MS with a release time of 6 weeks to<p>be obtained. The optimization of both the formulation and the encapsulation process allowed<p>maximum 13 % w/w Ab-loaded MS to be produced. It was demonstrated that the Ab-loaded PLGA MS were stable when stored at 5°C for up to 12 weeks and that the selection of the appropriate type of PLGA was critical to assuring the stability of the system. The better stability observed when using a PLGA characterized by a 75:25 lactide:glycolide ratio was attributed to<p>its slower degradation rate. Finally, the sustained release of Ab from the developed MS and the preservation of its activity was confirmed in vivo in a pharmacokinetic (pK) study realized in<p>rats. In conclusion, the application of the concept of entrapment into a polymer matrix for<p>stabilization and sustained release of biological compounds was demonstrated through this work.<p><p><p><p>RÉSUMÉ<p><p>Ce projet a pour but de développer un système de délivrance de médicament capable d’augmenter la stabilité et le temps de résidence in vivo des anticorps. Ce système sera administré par voie sous-cutanée et permettra un control précis de la libération du produit et de son niveau plasmatique. Cette plateforme technologique nous permettra de réduire la fréquence d’injection, de réduire potentiellement les effets secondaires et de maintenir des concentrations élevées en anticorps tout en améliorant la vie des patients atteints de maladies chroniques autoimmunes ou inflammatoires. Les formulations à base de polymères synthétiques, biodégradables (PLGA) ont été sélectionnés comme véhicules pour encapsuler les anticorps. Ils offrent en effet une bonne protection pour les anticorps and permettent une libération contrôlée de ceux-ci pendant une période définie. Après l’évaluation de différents méthodes d’encapsulation tels que les procédés d’eau-dans-huile-dans-eau (w/o/w) et solide-dans-huile-dans-eau (s/o/w), l’encapsulation des anticorps sous forme solide apparaissait plus apporpriée pour produire des microsphères de polymère chargées en anticorps. Cette technique nous permettait de maintenir l’anticorps sous sa forme monomérique et d’éviter la formation d’agrégats insolubles qui apparaissaient principalement à l’interface eau/huile. La première partie du projet a été d’optimiser à la fois la méthode nous permettant d’obtenir les anticorps sous forme de particules solides (spray-drying) et la méthode d’encapsulation de ces particules d’anticorps dans les microsphères de polymères. Cela a été réalisé par des plans d’expérience en utilisant une IgG bovine polyclonale comme molécule modèle. Durant l’optimisation du procédé de spray-drying,<p>les solutions aqueuses d’anticorps ont été atomisées en utilisant le mini Spray-Dryer assemblé avec une buse de pulvérisation d’un diamètre de 0.7 mm. En accord avec la taille particulaire (d(0.5) ~5 μm), la stabilité (absence de perte en monomère mesurée par chromatographie d’exclusion de taille et le rendement d’atomisation (> 60 % w/w), les paramètres d’atomisation ont été fixés: 3 mL/min pour le débit de liquide, 130°C /75°C pour la température d’entrée / température de sortie, 800 L/h pour le débit d’air d’atomisation et 30 m3/h pour le débit d’air de séchage. Pour le s/o/w, le dichlorométhane communément utilisé dans les procédés d’encapsulation a été remplacé par l’acétate d’éthyle qui est considéré comme un meilleure solvant organique en terme d’environnement et de sécurité. Les effets de plusieurs paramètres de fabrication ou de formulation ont été évalués sur les propriétés des microsphères polymériques d’anticorps (distribution de taille particulaire, taux de charge en anticorps, stabilité de l’anticorps et efficacité d’encapsulation). Plusieurs paramètres de fabrication et de formulation ont été statistiquement identifiés comme critiques pour obtenir un procédé reproductible (par exemple. La concentration en PLGA, le volume de phase externe, la vitesse d’émulsification et la quantité d’anticorps). La méthode d’encapsulation ainsi optimisée permettait d’obtenir un taux<p>de charge jusqu’à 6% (w/w) avec une efficacité d’encapsulation jusqu’à 60 % (w/w) tout en<p>préservant l’intégrité de l’anticorps encapsulé. Les microsphères produites étaient caractérisées<p>par un d(0.9) inférieur à 110 μm et montraient une libération après 24 h inférieure à 50 % (w/w).<p>Dans le seconde partie du projet, les procédés d’atomisation et d’encapsulation développés avec<p>l’IgG ont été appliqués à un anticorps monoclonal anti-TNF alpha humanisé pour confirmer la<p>conservation de l’activité de l’anticorps pendant ces procédés. La méthode s/o/w sélectionnée<p>permettait de produire des microsphères de PLGA chargées en anticorps avec un profil de libération jusqu’à 6 semaines et un maintien de la stabilité de l’actif. Afin de maintenir l’activité de l’anticorps, à la fois pendant le procédé d’encapsulation et pendant la libération, l’ajout d’un stabilisant tel que le tréhalose est apparu crucial ainsi que le choix du type de PLGA. Il a été démontré que l’utilisation du PLGA caractérisé par un ratio lactide :glycolide de 75 :25 (par exemple, Resomer ® RG755S) diminuait la formation d’espèces de faible poids moléculaire<p>pendant la dissolution. Cela contribuait à préserver l’activité de l’anticorps durant la libération à partir des microsphères. De plus, le profil de libération était modulé en fonction du type de polymère et de sa concentration. Par exemple, l’utilisation d’une solution à 10 % w/v RG755S conduisait à la production de microsphères d’anticorps avec un temps de libération sur 6<p>semaines. L’optimisation de la formulation et du procédé d’encapsulation a permis de produire<p>des microsphères avec des taux de charge en anticorps de maximum 13 % w/w. Il a été démontré<p>que ces microsphères, stockées à 5°C, étaient stables jusqu’à 12 semaines et que la sélection du<p>type de PLGA était critique pour assurer la stabilité du système. La meilleure stabilité a été<p>obtenue en utilisant le PLGA caractérisé par un ratio lactide :glycolide de 75 :25. Cela a été<p>attribué à sa plus faible vitesse de dégradation. Enfin, la libération contrôlée de l’anticorps à<p>partir de ces microsphères et la conservation de son activité ont été confirmées in vivo lors d’une<p>étude pharmacocinétique réalisée chez le rat. En conclusion, ce travail a permis de démontrer<p>l’application du concept d’ « emprisonnement » des composés biologiques dans des matrices<p>polymériques afin de les stabiliser et contrôler leur libération.<br>Doctorat en Sciences biomédicales et pharmaceutiques<br>info:eu-repo/semantics/nonPublished

APA, Harvard, Vancouver, ISO, and other styles

More sources

Books on the topic "Sustained and controlled release"

1

M, MacLeod Stuart, and Szefler S. J, eds. Childhood asthma and sustained release theophylline: International workshop, Whistler, Canada. Excerpta Medica, 1986.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

2

Fan, Liang-tseng, and Satish Kumar Singh. Controlled Release. Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-74507-2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

J, Norris R., Wale Laurence, and Revlon Health Care Group, eds. Sustained release verapamil workshop. Medical News Tribune Group, 1985.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

4

Lee, Ping I., and William R. Good, eds. Controlled-Release Technology. American Chemical Society, 1987. http://dx.doi.org/10.1021/bk-1987-0348.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Keen, Fiona Eleanor. Controlled release antioxidants. University of Birmingham, 1989.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

6

Kyodonieus, Agis F. Controlled Release Technologies. Routledge, 2022. https://doi.org/10.1201/9780429297724.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Varadachari, Chandrika. Slow-release and controlled-release nitrogen fertilizers. Published by Indian Nitrogen Group, Society for Conservation of Nature in association with South Asian Nitrogen Centre, International Nitrogen Initiative, 2010.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

8

Purkiss, Ronald. Bioequivalence of sustained release theophylline formulations. Aston University. Department of Pharmaceutical Sciences, 1986.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

9

Dinh, Steven M., John D. DeNuzzio, and Ann R. Comfort, eds. Intelligent Materials for Controlled Release. American Chemical Society, 1999. http://dx.doi.org/10.1021/bk-1999-0728.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

M, Dinh Steven, DeNuzzio John D. 1959-, and Comfort Ann R. 1960-, eds. Intelligent materials for controlled release. American Chemical Society, 1999.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

More sources

Book chapters on the topic "Sustained and controlled release"

1

Sharma, Shivangi, Neeru Dabas, Deepa Sharma, Mohit Kumar, Sanjay Kumar Kataria, and Gautam Jaiswar. "Smart Materials for Sustained and Controlled Drug Release." In Smart Micro- and Nanomaterials for Pharmaceutical Applications. CRC Press, 2024. http://dx.doi.org/10.1201/9781003468431-12.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Ganguly, Sayan, and Shlomo Margel. "General Overview of Controlled and Sustained Release Systems." In Handbook of Nutraceuticals. Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-030-69677-1_22-1.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Sharma, Kartikey, and Vandana Guleria. "Adoption of Smart Materials for Sustained and Controlled Drug Release." In Smart Micro- and Nanomaterials for Drug Delivery. CRC Press, 2024. http://dx.doi.org/10.1201/9781003468424-16.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Toews, Parker M., and Jeffrey S. Bates. "Molecular Imprinted Hydrogels for the Controlled and Sustained Release of Hydrophilic Drug Therapy." In Methods in Molecular Biology. Springer US, 2025. https://doi.org/10.1007/978-1-0716-4402-7_8.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Kumar, Amrish, Sunil K. Jain, Dinesh K. Mishra, and Rupesh Gautam. "Influence of Drug Properties and Routes of Drug Administration on Design of Sustained and Controlled Release Systems." In Novel Carrier Systems for Targeted and Controlled Drug Delivery. Springer Nature Singapore, 2024. https://doi.org/10.1007/978-981-97-4970-6_1.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Nahler, Gerhard. "sustained release." In Dictionary of Pharmaceutical Medicine. Springer Vienna, 2009. http://dx.doi.org/10.1007/978-3-211-89836-9_1374.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Tadros, Tharwat. "Controlled Release." In Encyclopedia of Colloid and Interface Science. Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-20665-8_56.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Huynh, Cong Truc, and Doo Sung Lee. "Controlled Release." In Encyclopedia of Polymeric Nanomaterials. Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-36199-9_314-1.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Smith, Kelly L., and Scott M. Herbig. "Controlled Release." In Membrane Handbook. Springer US, 1992. http://dx.doi.org/10.1007/978-1-4615-3548-5_47.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Altinkaya, Sacide Alsoy. "Controlled Release." In Encyclopedia of Membranes. Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-44324-8_1236.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Conference papers on the topic "Sustained and controlled release"

1

Viglione, Jennavieve F., and Ali Kiapour. "Controlled Release Transdermal Patch." In 2024 IEEE MIT Undergraduate Research Technology Conference (URTC). IEEE, 2024. https://doi.org/10.1109/urtc65039.2024.10937605.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Li, Wenyan, and Luz M. Calle. "Controlled Release Microcapsules for Smart Coatings." In CORROSION 2007. NACE International, 2007. https://doi.org/10.5006/c2007-07228.

Full text

Abstract:

Abstract Corrosion in service is a serious problem for most military operations. The cost of corrosion includes manpower, materials used to repair corrosion damage, equipment downtime, and reduced capacity due to corrosion damage. A considerable number of corrosion problems can be solved by coatings. However, even the best protective coatings can fail by allowing the slow diffusion of oxygen and moisture to the metal surface. Corrosion accelerates when a coating delaminates. Often, the problems start when microscopic nicks or pits on the surface develop during manufacturing or through wear and tear. This problem can be solved by the incorporation of a self-healing function into the coating. Several new concepts are currently under development to incorporate this function into a coating. Conductive polymers, nanoparticles, and microcapsules are used to release corrosion-inhibiting ions at a defect site. The objective of this investigation is to develop a smart coating for the early detection and inhibition of corrosion. The dual function of this new smart coating system is performed by pH-triggered release microcapsules. The microcapsules can be used to deliver healing agents to terminate the corrosion process at its early stage or as corrosion indicators by releasing dyes at the localized corrosion sites. The dyes can be color dyes or fluorescent dyes, with or without pH sensitivity. Corrosion indicator (pH indicator) and corrosion inhibitor containing microcapsules were formed and incorporated into paint systems. Test panels of selected steels and aluminum alloys were coated using these paints. Testing of compatibility between the microcapsule system and different paint systems are in progress. Initial experiments with the microcapsule containing paint show visible color changes at induced corrosion sites and improvement of corrosion protection. Further investigation of the performance of the coating using electrochemical techniques and long-term exposure is currently underway.

APA, Harvard, Vancouver, ISO, and other styles

3

Makovik, I. N., A. V. Dunaev, E. U. Rafailov, and V. V. Dremin. "Controlled Photosensitizer-free Singlet Oxygen Release for Biomedical Applications." In 2024 International Conference Laser Optics (ICLO). IEEE, 2024. http://dx.doi.org/10.1109/iclo59702.2024.10624325.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Starly, Binil, Shih-Feng Lan, and David Schmidtke. "Customized Release of Metronidazole From Composite Casted Rings of Poly-Caprolactone/Alginate for Periodontal Drug Delivery." In ASME 2013 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/sbc2013-14177.

Full text

Abstract:

Dental implants provide support for dental crowns and bridges by serving as abutments for the replacement of missing teeth. The objective of this study was to demonstrate a novel method of controlled localized delivery of antibacterial agents to an implant site using a custom fabricated ring. The study involved incorporating a model antibacterial agent (metronidazole) into custom designed Poly-ε-Caprolactone/Alginate (PCL/Alginate) composite rings to produce the intended controlled release profile. In vitro release studies indicate that pure (100%) alginate rings exhibited an expected burst release of metronidazole in the first few hours, whereas Alginate/PCL composite rings produced a medium burst release followed by a sustained release for a period greater than 4 weeks. By varying the PCL/Alginate weight ratios, we have shown that we can control the amount of antibacterial agents released to provide the minimal inhibitory concentration needed for adequate protection. The developed system demonstrates a controllable drug release profile and the potential for the ring to inhibit bacterial biofilm growth for the prevention of diseases such as peri-implantitis resulting from bacterial infection at the implant site.

APA, Harvard, Vancouver, ISO, and other styles

5

Wu, Juan, Aipeng Deng, Wei Jiang, Renbing Tian, Wei Jiang, and Yewen Shen. "Synthesis and characterization of pH-sensitive magnetic nanoparticles as drug carriers for sustained and controlled release of MTX." In 2016 IEEE 16th International Conference on Nanotechnology (IEEE-NANO). IEEE, 2016. http://dx.doi.org/10.1109/nano.2016.7751295.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Banerjee, Rupak K., Robert J. Lutz, Keyvan Keyhani, Robert L. Dedrick, Brian King, and Michael Robinson. "Comparison of Drug Distribution Between Intravitreal Injection and a Controlled–Release Implant in a Rabbit Eye." In ASME 2000 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/imece2000-2235.

Full text

Abstract:

Abstract Due to physiological barriers within the eye, which limit penetration of many drugs from the systemic circulation into the vitreous, the most common method of treating retinal disease is direct intravitreal injection. However, this common procedure may be inappropriate for a wide range of drugs as it may lead to highly variable concentrations potentially causing higher toxicity for tissues inside the eye and limiting therapeutic effect. A recent procedure is to use surgically implanted drug release device, called implant here, in the vitreous of the eye that allow controlled release of drug over a sustained period of time. For constant release of drug over 15 hours, a substantial reduction in peak drug concentration is predicted near the retina. When compared with the implant, a doubling of drug concentration would be expected for more than 3 hours near the retina for the intravitreal injection.

APA, Harvard, Vancouver, ISO, and other styles

7

Spurr, N., D. Stanley, M. Usie, F. Debenedictis, D. Schneider, and A. Lawler. "Deepwater Application of Proppant Controlled Release Inhibitor Leads to Successful Well Production in Gulf of Mexico." In SPE International Conference and Exhibition on Formation Damage Control. SPE, 2024. http://dx.doi.org/10.2118/217845-ms.

Full text

Abstract:

Abstract Designing and achieving a deep-water frac pack in a new field that delivers low drawdown/low skin and high PI's is always a challenge. Successful design work, planning and execution are all key parameters. With additional challenges of a suspected high asphaltene content crude oil with relatively low onset pressures (AOP), another challenge was posed, "Can you place a solid inhibitor during the completion phase that can prolong expensive remediation treatments, while maximizing value by adjusting the chemical release pressure?" A new solid, controlled release proppant like inhibitor was introduced with a custom designed release pressure close to that of the AOP to solve the operator problem. Frac packs were designed aggressively to achieve high net pressures, which historically achieve low drawdowns, low skin, and high PI's, and consequentially reduce the asphaltene deposition tendencies of the crude due to pressure drops. The controlled release asphaltene inhibitor proppant was tested for performance via asphaltene dispersion testing to ensure inhibitor performance and to obtain a minimum recommended loading. To further determine the best treatment for a new field development of two subsea tieback wells, reservoir conditions, AOP and desired protection points were evaluated. The optimized fracturing design and custom controlled release asphaltene inhibitor proppant for the five treatment zones resulted in higher than expected PI's, lower than expected skins and overall exceptional wells. To date, no asphaltene deposition has been suspected and completion skin has remained low. This paper introduces the next generation of flow assurance proppants that release asphaltene inhibitor when the well needs it the most and close to the AOP leading to less formation damage and a sustained production.

APA, Harvard, Vancouver, ISO, and other styles

8

Giammancheri, M., G. Tassone, Gabriel Carpineta, et al. "Infused Scale-Inhibitor Proppant Ensures Sustained Production Assurance Strategy Against Scale Deposition in Multi-Fractured Wells." In SPE International Hydraulic Fracturing Technology Conference and Exhibition. SPE, 2023. http://dx.doi.org/10.2118/215716-ms.

Full text

Abstract:

Abstract This paper describes the production assurance strategy adopted to resolve scaling deposition in hydraulically fractured wellbores by means of incorporating a ceramic proppant infused with a controlled release scale inhibitor in the primary completion. This chemical delivery system has been applied as an integral component in the offshore field development program and yielded positive results. Production assurance and scale inhibition chemicals are traditionally injected via a dedicated capillary in the production string, but this approach is often not very efficient or effective as a prevention strategy due to the uncertainty surrounding the severity and timing of the phenomenon. Contributing factors to the scale deposition include variations in the water production rate, water breakthrough from water flooding and changes in the bottom hole flowing pressure and temperature. These variable conditions also complicate the scaling prediction efforts. A ceramic proppant based chemical delivery system was selected to ensure multiyear inhibition of scale with a onetime treatment. The engineered ceramic proppant provides effective chemical delivery, high fracture conductivity and strength so it can be used to replace part of the proppant in hydraulic fracturing and frac pack completions or be incorporated into a gravel pack completion. The strategy was successfully applied in a field in West Africa. Significant learnings from this implementation of controlled release scale technology in the primary completion was realized. The controlled release of the scale-inhibiting chemical into the production stream as it flows through the proppant pack effectively prevents scaling in the fracture, the wellbore, and completion string to surface. The key concept was to eliminate the uncertainty surrounding the onset of the scaling problems, which inevitably results during well selection process due to the variation in water production and chemistry among the wells. Another important goal was to also reduce the frequency of costly interventions in an offshore operating environment and to maximize well and field production uptime. The field application of this delivery system has successfully eased the operational challenges being observed in offset wells which otherwise require repeated treatments of scale inhibitor. Operational benefits resulted from the increased free space on the platform and eliminated any need of well interventions for remedial scale control on these treated wells. The information presented in this paper will benefit production engineers facing similar scale and production challenges and seeking a comprehensive production assurance strategy and desire a cost-effective solution. The application of infused scale inhibitor proppant has shown to provide production assurance as a onetime treatment, regardless of well type, and can provide a sustained multi-year scale prevention solution.

APA, Harvard, Vancouver, ISO, and other styles

9

Li, Xinyan, and Dan Zhao. "Feedback Control of Self-Sustained Nonlinear Combustion Oscillations." In ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-42126.

Full text

Abstract:

Detrimental combustion instability is unwanted in gas turbines, aeroengines and rocket motors. It is typically generated due to the dynamic coupling between unsteady heat release and acoustic pressure. To prevent the onset of combustion instability or dampen large-amplitude oscillations, the coupling must somehow be interrupted. In this work, we design and implement a sliding mode controller and observer to mitigate self-sustained combustion oscillations in an open-ended thermoacoustic system. An acoustically compact heat source is confined and modeled by using a modified form of King’s Law. Coupling the heat source model with a Galerkin series expansion of the acoustic pressure provides an approach to evaluate the performance of the sliding mode control. The thermoacoustic systems with different numbers of eigenmodes and actuators are considered. It is found that self-sustained limit cycle oscillations can be successfully produced from small perturbations in the thermoacoustic systems when the actuators are not actuated. Meanwhile, the system we modeled can be proved to be controllable and observable. In order to gain insight on the thermoacoustic mode selection and triggering, the acoustical energy exchange between neighboring eigenmodes are studied and discussed. As the controller-driven actuators are actuated, the limit cycle oscillations are quickly dampened. And both thermoacoustic systems are stabilized. The successful demonstration indicates that the sliding mode controller can be applied to stabilize unstable thermoacoustic systems, even with multiple eigenmodes.

APA, Harvard, Vancouver, ISO, and other styles

10

Alhajeri, Mubarak Muhammad, Jenn-Tai Liang, and Reza Barati Ghahfarokhi. "Polyelectrolyte Multilayered Nanoparticles as Nanocontainers for Enzyme Breakers During Hydraulic Fracturing Process." In SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/205981-ms.

Full text

Abstract:

Abstract In this study, Layer-by-Layer (LbL) assembled polyelectrolyte multilayered nanoparticles were developed as a technique for targeted and controlled release of enzyme breakers. Polyelectrolyte multilayers (PEMs) were assembled by means of alternate electrostatic adsorption of polyanions and polycations using colloidal structure of polyelectrolyte complexes (PECs) as LbL building blocks. High enzyme concentrations were introduced into polyethyleneimine (PEI), a positively charged polyelectrolyte solution, to form an electrostatic PECs with dextran sulfate (DS), a negatively charged polyelectrolyte solution. Under the right concentrations and pH conditions, PEMs were assembled by alternating deposition of PEI with DS solutions at the colloidal structure of PEI-DS complexes. Stability and reproducibility of PEMs were tested over time. This work demonstrates the significance of PEMs as a technique for the targeted and controlled release of enzymes based on their high loading capacity, high capsulation efficiency, and extreme control over enzyme concentration. Entrapment efficiency (EE%) of polyelectrolyte multilayered nanoparticles were evaluated using concentration measurement methods as enzyme viscometric assays. Controlled release of enzyme entrapped within PEMs was sustained over longer time periods (&gt; 18 hours) through reduction in viscosity, and elastic modulus of borate-crosslinked hydroxypropyl guar (HPG). Long-term fracture conductivity tests at 40℃ under closure stresses of 1,000, 2,000, and 4,000 psi revealed high fracture clean-up efficiency for fracturing fluid mixed with enzyme-loaded PEMs nanoparticles. The retained fracture conductivity improvement from 25% to 60% indicates the impact of controlled distribution of nanoparticles in the filter cake and along the entire fracture face as opposed to the randomly dispersed unentrapped enzyme. Retained fracture conductivity was found to be 34% for fluid systems containing conventional enzyme-loaded PECs. Additionally, enzyme-loaded PEMs demonstrated enhanced nanoparticle distribution, high loading and entrapment efficiency, and sustained release of the enzyme. This allows for the addition of higher enzyme concentrations without compromising the fluid properties during a treatment, thereby effectively degrading the concentrated residual gel to a greater extent. Fluid loss properties of polyelectrolyte multilayered nanoparticles were also studied under static conditions using a high-pressure fluid loss cell. A borate-crosslinked HPG mixed with nanoparticles was filtered against core plugs with similar permeabilities. The addition of multilayered nanoparticles into the fracturing fluid was observed to significantly improve the fluid- loss prevention effect. The spurt-loss coefficient values were also determined to cause lower filtrate volume than those with crosslinked base solutions. The PEI-DS complex bridging effects revealed a denser, colored filter cake indicating a relatively homogenous dispersion and properly sized particles in the filter cake.

APA, Harvard, Vancouver, ISO, and other styles

Reports on the topic "Sustained and controlled release"

1

Mukhtar, Hasan. Sustained Release Oral Nanoformulated Green Tea for Prostate Cancer. Defense Technical Information Center, 2011. http://dx.doi.org/10.21236/ada545577.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Mukhtar, Hasan. Sustained Release Oral Nanoformulated Green Tea for Prostate Cancer Prevention. Defense Technical Information Center, 2013. http://dx.doi.org/10.21236/ada585226.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Mukhtar, Hasan, Nihal Ahmad, Vaqar M. Adhami, and Naghma Khan. Sustained Release Oral Nanoformulated Green Tea for Prostate Cancer Prevention. Defense Technical Information Center, 2012. http://dx.doi.org/10.21236/ada589659.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Chutimaworapan, Suchada, Chaiyo Chaichantippayuth, and Areerat Laopaksa. Formulation of pharmaceutical products of Garcinia mangostana Linn. extracts. Chulalongkorn University, 2006. https://doi.org/10.58837/chula.res.2006.32.

Full text

Abstract:

Part I: The purpose of the investigation was to develop the extraction process that was simple, practical and giving high yield. The maceration of dried powder of Garcinia mangostana fruit husk with ethyl acetate gave yellow crystalline powder of mangostin. The yield was calculated as 7.47%. The identification of the Garcinia mangostanahusk extract was carried out by thin-layer chromatography (TLC) and differential scanning calorimetry. The TLC of mangostin was done by using the alumina sheet and ethyl acetate: hexane (3:1) as mobile phase. The Rf value as compared with standard mangostin was 0.60. The DSC thermogram showed the board melting range of the crude extract at 165.04-166.80 °C. The quantitative analyses of mangostin were developed using the high performance liquid chromatography (HPLC) and ultraviolet (UV) spectrophotometry. The HPLC system using methanol: water (87:13) as mobile phase, clotrimazole as internal standard and using UV detector at 243 nm. The UV spectrophotometric method was carried out using the UV spectrophotometer at 243 nm. The validation of both systems gave high specificity, linearity, accuracy and precision. The solubility study of mangostin showed the low water insolubility. The water solubility was improving with increasing ethanol content. The in vitro microbiological activity of mangostin to Staphylococcus aureus ATCC 25923 and Streptococcus mutans ATCC KPSK2 was studied. The minimum inhibitory concentrations of the extract were 3 µg/ml and 1.5 µg/ml, respectively. The minimum bactericidal concentrations of the extract was 4 µg/ml and 3 µg/ml, respectively.Part II: The purpose of this study was to develop fast dissolving oral strips containing Garcinia mangostana husk extract. The films consisted of low viscosity hydrophilic polymers such as hydroxypropyl methylcellulose and hydroxypropylcellulose, acesulfame potassium as sweetener, and menthol and eucalyptus oil as flavoring agents. The physical and mechanical properties and dissolution time of film bases were compared with commercial product strips A. From the dissolution time data, it was found that the film prepared from mixed polymer between HPMC 3 cps and HPC LV at ratios 2:1, 3:1, 4:1 and 5:1 were not significantly different from commercial product strips A (p>0.05). The films containing extract were light yellow and had porous surface based on observation from scanning electron microscopy. The dissolution profiles of all formulations showed the rapid release more than 80 percent of mangostin from films within 3-7 minutes and the fastest release was from formulation of HPMC 3 cps and HPC LV at ratio 5:1. Differential scanning calorimetry results exhibited that the Garcinia mangostana extract and additives were not in crystalline form in the films. The fast dissolving oral strips containing Garcinia mangostana husk extract showed in vitro antimicrobial activity against oro-dental bacteria, namely, Staphylococcus aureus aTCC 25923 and Streptococcus mutans ATCC KPSK2. Unter strese conditions at 40 degree Celcius and 75 percent relative humidity, the strips showed a good stability.The purpose of the study was to develop monoglyceride-based drug delivery systems containing Garcinia Mangostana extract. The system is based on the ability of mixtures of monoglyceride (dlyceryl monooleate) and triglycerides to form liquid crystals upon contact with water. The drug delivery systems can be administered by syringe and transformed into high-viscous liquid crystalline phases at the injection site. Ternary phase diagrams were constructed from various triglycerides: sesame oil, soybean oil and olive oil. In this study, monoglyceride-based drug delivery systems were prepared in the ratio of triglycerides: monoglyceride: water as 8: 62: 30 and 12: 58: 30. These systems could sustain release of Garcinia Mangostana husk extract over a period of 48 hr and followed squared root of time kinetics during the initial 24 hr of the release phase, indicating that the rate of release was diffusion-controlled. The system containing sesame oil showed the highest drug release. The increasing triglyceride content did not affect the release profiles. Differential scanning calorimetry results demonstrated that Garcinia Mangostana husk extract could be incorporated into drug delivery systems without causing phase transition. In the in vitro test, monoglyceride-based drug delivery systems containing Garcinia mangostana husk extract did not show the antimicrobial activity probably due to the high lipophilicity of the extract therefore it did not diffuse into the medium. Additionally, the drug delivery systems containing Garcinia mangostana husk extract showed good stability under the stress condition.

APA, Harvard, Vancouver, ISO, and other styles

5

Randen, Neil A. Controlled-Release Personal Use Arthropod Repellent Formulation. Phase 2. Defense Technical Information Center, 1986. http://dx.doi.org/10.21236/adb112150.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Randen, Neil A. Controlled-Release Personal Use Arthropod Repellent Formulation. Phase 3. Defense Technical Information Center, 1987. http://dx.doi.org/10.21236/adb116939.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Killorn, Randy, Marianela Gonzalez, Jeffrey Moore, and David Haden. Effect of Controlled-Release N Fertilizer on Corn Grain Yield. Iowa State University, Digital Repository, 2006. http://dx.doi.org/10.31274/farmprogressreports-180814-621.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Citarrella, Maria Clara, Emmanuel Fortunato Gulino, and Roberto Scaffaro. Green composites for fertilizer controlled release produced by compression molding and FDM. Peeref, 2023. http://dx.doi.org/10.54985/peeref.2303p8203188.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Sirivat, Anuvat. Electrically controlled release of drugs from alginate hydrogels for transdermal drug delivery application. Chulalongkorn University, 2014. https://doi.org/10.58837/chula.res.2014.80.

Full text

Abstract:

A drug-loaded conductive polymer/hydrogel blend, benzoic acid-loaded poly(3,4-ethylenedioxythiophene/alginate (BA-loaded PEDOT/Alg) hydrogel, was used as a carrier/matrix for an electrical stimuli transdermal drug delivery system (TDDS). The effects of crosslinking ratio, PEDOT particle size, and electric field strength on the release mechanism and the diffusion coefficient (D) of BA were examined by using a modified Franz-diffusion cell. The diffusion scaling exponent value of BA is close to 0.5 which refers to the diffusion controlled mechanism, or the Fickian diffusion as the BA release mechanism. The D increased when there was a decrease in the crosslinking ratio due to the mesh size-hindering effect. When increasing electric field strength, the D of BA-loaded PEDOT/Alg hydrogel increased because the cathode-BA electrorepulsion, electro-induced alginate expansion, and PEDOT electro-neutralization simultaneously occurred. The highest D belonged to a blend with the smallest PEDOT particle and highest electrical conductivity. The D of BA was a function of the matrix mesh size except when drug size/mesh size was lower than 2.38x10³, where D of BA became mesh size independent as the matrix mesh size was extremely large. Thus, the fabricated conductive polymer hydrogel blends have a great potential to be used in TDDS under electrical stimulation.

APA, Harvard, Vancouver, ISO, and other styles

10

Kardon, Randy. Treatment of Laser-Induced Retinal Injury and Visual Loss Using Sustained Release of Intra-Vitreal Neurotrophic Growth Factors. Addendum. Defense Technical Information Center, 2011. http://dx.doi.org/10.21236/ada558524.

Full text

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!