Academic literature on the topic 'Pharmaceutical emulsions'
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Journal articles on the topic "Pharmaceutical emulsions"
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Fu, Wei, Yang Liu, Chen Yang, Wen Hua Wang, Man Wang, and Yuan Yuan Jia. "Stabilization of Pickering Emulsions by Bacterial Cellulose Nanofibrils." Key Engineering Materials 645-646 (May 2015): 1247–54. http://dx.doi.org/10.4028/www.scientific.net/kem.645-646.1247.
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In order to develop safe and sustainable food and pharmaceutical emulsions, bacterial cellulose (BC) nanofibrils were prepared to stabilize maize oil/water Pickering emulsions. The influence of BC content and pH value on the emulsion stability was explored. Droplet diameters decreased with BC contents in emulsions. At pH 12, the emulsions were most stable among all tested pH values. The transformation of emulsion structure from liquid to gel-like at 8-15°C with BC content higher than 1.55 g/L is predominantly depended on the viscoelastic entangled BC network. These results can have meaningful inspiration of designing edible food and pharmaceutical emulsions.
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Sovilj, Verica, Jelena Saletic, Lidija Petrovic, and Petar Dokic. "Properties of hydroxypropylmethyl cellulose stabilized emulsion in the presence of sodium dodecylsulfate." Acta Periodica Technologica, no. 35 (2004): 141–48. http://dx.doi.org/10.2298/apt0435141s.
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Many food, pharmaceutical, cosmetic and chemical products exist in the form of emulsions. A common problem with emulsions is their instability. One method of effective protection against coalescence of the particles is to raise the viscosity and lower surface tension by adding a polymer and low-molar-mass surfactant. Interaction between polymer and surfactant could change the adsorption layer around the oil droplets in emulsion which effects emulsion stability. In this paper, the influence of low-molar-mass anionic surfactant, sodium dodecylsulfate (SDS), on the properties of hydroxypropylmethyl cellulose (HPMC) stabilized emulsion, has been investigated. Changes of viscosity and rheological properties of emulsion caused by the HPMC-SDS interaction in continuous phase were measured and stability of emulsions was observed during two months of storage. Significant increase in viscosity and stability of the emulsions was found at SDS concentrations leading to HPMC-SDS interaction in the continuous phase. Stability of emulsions changed with time and was influenced by the HPMC-SDS interaction.
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Khan, Barkat Ali, Naveed Akhtar, Haroon Khan, and Valdir de Andrade Braga. "Development, characterization and antioxidant activity of polysorbate based O/W emulsion containing polyphenols derived from Hippophae rhamnoides and Cassia fistula." Brazilian Journal of Pharmaceutical Sciences 49, no. 4 (December 2013): 763–73. http://dx.doi.org/10.1590/s1984-82502013000400016.
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The objective of this study was to develop a pharmaceutical O/W emulsion containing plant-derived polyphenol extracts and evaluate its stability and antioxidant activity. O/W emulsions were prepared using ionic surfactant polysorbate 80 (Tween 80®). The odorwas adjusted with few drops of blue sea fragrance. DPPH (1,1-diphenyl-2-picrylhydrazyl) assay was used to evaluate the antioxidant activity of the plant extracts alone and emulsions containing these extracts. Physical stability was assessed by submitting the emulsions to storage at 8 ºC, 25 ºC, 40 ºC and 40 ºC + 70% RH (relative humidity) for two months. Various physical characteristics of emulsions monitored, include color, creaming, liquefaction, centrifugation and pH. Brookfield rotational rheometer was used to determined viscosities and rheological behavior of emulsions. Different types of emulsion were determined microscopically, while pH values of emulsions were measured by a pH meter. Electrical conductivity data confirmed that the outer phase was water. Samples presented an acceptable pH value for an external topical use. Shear thinning behaviour was observed for all emulsions. The polyphenol-rich-plant-derived extracts alone and the extract containing emulsions showed good antioxidant activities. This research confirmed that the method used was suitable for preparing emulsions with Hippophae rhamnoids and Cassia fistula extracts, suggesting that those emulsions are suitable for topical use.
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Bastola, Rakesh, Jo-Eun Seo, Taekwang Keum, Gyubin Noh, Jae Woong Choi, Jong Il Shin, Ju Hun Kim, and Sangkil Lee. "Preparation of Squalene Oil-Based Emulsion Adjuvants Employing a Self-Emulsifying Drug Delivery System and Assessment of Mycoplasma hyopneumoniae-Specific Antibody Titers in BALB/c Mice." Pharmaceutics 11, no. 12 (December 10, 2019): 667. http://dx.doi.org/10.3390/pharmaceutics11120667.
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In this study, a self-emulsifying drug delivery system (SEDDS) was employed to prepare novel squalene oil-based emulsion adjuvants. Deionized water, 0.01% and 0.02% (w/v) carbomer solutions of C-971P NF and C-940 grades were used to prepare emulsions containing 3%, 5% and 10% of squalene oil. Altogether 15 candidate emulsions were prepared and used as adjuvants for the delivery of a combination vaccine containing a porcine circovirus type 2 (PCV2) antigen and inactivated Mycoplasma hyopneumoniae (J101 strain) antigen. Most of the emulsions showed droplet sizes in the submicron range and maintained zeta potential values between −40 mV to 0 mV for six months, indicating good physical stability as a vaccine adjuvant. Emulsion-based candidate adjuvants prepared with SEDDS technology stimulated IgG, IgG1 and IgG2a like a currently commercially available adjuvant, Montanide ISATM 201, and they were safe and their Mycoplasma hyopneumoniae-specific antibody titers were considered as comparable with that of Montanide ISATM 201.
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Abruzzo, Angela, Bruno Saladini, Francesco Dalena, Fiore P. Nicoletta, Barbara Luppi, Federica Bigucci, and Teresa Cerchiara. "Dry Emulsions based on Alpha Cyclodextrin and Vegetable Oils for Buccal Delivery of Lipophilic Drugs." Drug Delivery Letters 10, no. 3 (September 10, 2020): 219–27. http://dx.doi.org/10.2174/2210303110666200303125449.
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Background: Buccal delivery of drugs can be used as an alternative administration route to conventional oral route avoiding the liver first-pass effect and improving patient compliance. Objective: The goal of this work was to develop dry emulsions for buccal delivery of ketoprofen, used as a lipophilic model drug. The influence of two vegetable oils, olive oil or wheat germ oil, in the presence of α-cyclodextrin and different drying techniques on the dry emulsion properties was evaluated. Methods: Emulsions were prepared by adding olive oil or wheat germ oil to an aqueous solution of α-cyclodextrin and subsequently dried through an oven, freeze-dryer or spray-dryer. Dry emulsions were characterized in terms of yield, encapsulation efficiency, morphology and drug solid-state. In vitro drug release and permeation studies were carried out to evaluate dry emulsion ability to release the drug and to allow its permeation through the esophageal porcine epithelium. Results: The formation of stable and milky emulsion was assured by cyclodextrin ability to interact with oil components obtaining an inclusion complex with amphiphilic property able to act as a surfaceactive agent. The drying process influenced the yield and the encapsulation efficiency, while no significant differences were observed between olive oil and wheat germ oil. Freeze-dried emulsions, selected as the best formulations, resulted in fast release of drug thereby ensuring its permeation across the epithelium. Conclusion: Dry emulsions prepared with a simple and easy method, using natural ingredients and avoiding synthetic surfactants and organic solvents, could be used for buccal delivery of lipophilic drugs.
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Lallemand, Frederic, Philippe Daull, Simon Benita, Ronald Buggage, and Jean-Sebastien Garrigue. "Successfully Improving Ocular Drug Delivery Using the Cationic Nanoemulsion, Novasorb." Journal of Drug Delivery 2012 (February 27, 2012): 1–16. http://dx.doi.org/10.1155/2012/604204.
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Topical ophthalmic delivery of active ingredients can be achieved using cationic nanoemulsions. In the last decade, Novagali Pharma has successfully developed and marketed Novasorb, an advanced pharmaceutical technology for the treatment of ophthalmic diseases. This paper describes the main steps in the development of cationic nanoemulsions from formulation to evaluation in clinical trials. A major challenge of the formulation work was the selection of a cationic agent with an acceptable safety profile that would ensure a sufficient ocular surface retention time. Then, toxicity and pharmacokinetic studies were performed showing that the cationic emulsions were safe and well tolerated. Even in the absence of an active ingredient, cationic emulsions were observed in preclinical studies to have an inherent benefit on the ocular surface. Moreover, clinical trials demonstrated the efficacy and safety of cationic emulsions loaded with cyclosporine A in patients with dry eye disease. Ongoing studies evaluating latanoprost emulsion in patients with ocular surface disease and glaucoma suggest that the beneficial effects on reducing ocular surface damage may also extend to this patient population. The culmination of these efforts has been the marketing of Cationorm, a preservative-free cationic emulsion indicated for the symptomatic treatment of dry eye.
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Akram, Salman, Nicolas Anton, Ziad Omran, and Thierry Vandamme. "Water-in-Oil Nano-Emulsions Prepared by Spontaneous Emulsification: New Insights on the Formulation Process." Pharmaceutics 13, no. 7 (July 7, 2021): 1030. http://dx.doi.org/10.3390/pharmaceutics13071030.
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Nano-emulsions consist of stable suspensions of nano-scaled droplets that have huge loading capacities and are formulated with safe compounds. For these reasons, a large number of studies have described the potential uses of nano-emulsions, focusing on various aspects such as formulation processes, loading capabilities, and surface modifications. These studies typically concern direct nano-emulsions (i.e., oil-in-water), whereas studies on reverse nano-emulsions (i.e., water-in-oil) remain anecdotal. However, reverse nano-emulsion technology is very promising (e.g., as an alternative to liposome technology) for the development of drug delivery systems that encapsulate hydrophilic compounds within double droplets. The spontaneous emulsification process has the added advantages of optimization of the energetic yield, potential for industrial scale-up, improved loading capabilities, and preservation of fragile compounds targeted for encapsulation. In this study, we propose a detailed investigation of the processes and formulation parameters involved in the spontaneous nano-emulsification that produces water-in-oil nano-emulsions. The following details were addressed: (i) the order of mixing of the different compounds (method A and method B), (ii) mixing rates, (iii) amount of surfactants, (iv) type and mixture of surfactants, (v) amount of dispersed phase, and (vi) influence of the nature of the oil. The results emphasized the effects of the formulation parameters (e.g., the volume fraction of the dispersed phase, nature or concentration of surfactant, or nature of the oil) on the nature and properties of the nano-emulsions formed.
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Avlani, Dhruti, Vaibhav Agarwal, Vansh Khattry, Gopa Roy Biswas, and Sutapa Biswas Majee. "EXPLORING PROPERTIES OF SWEET BASIL SEED MUCILAGE IN DEVELOPMENT OF PHARMACEUTICAL SUSPENSIONS AND SURFACTANT-FREE STABLE EMULSIONS." International Journal of Applied Pharmaceutics 11, no. 1 (January 9, 2019): 124. http://dx.doi.org/10.22159/ijap.2019v11i1.29877.
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Objective: The objective of the investigation was to isolate mucilage from sweet basil seeds and explore its physicochemical properties for the development of pharmaceutical suspensions and surfactant-free stable emulsions.Methods: Possible applications of sweet basil seed mucilage in the pharmaceutical field for dosage form development are being explored. The physicochemical and functional properties of the mucilage from the seeds of the Ocimum basilicum L. (Sweet basil) have been investigated for stabilization of suspensions and emulsions. The following analyses were performed: FTIR spectroscopy, phytochemical tests, XRD, swelling and rheological studies.Results: The analyses showed that the mucilage is rich in glucose, mannose, and xylose. High swelling index values varying from 100±10 to 200±13%, high water-holding capacity of 97.5±2.4 g/g mucilage and reasonable oil holding capacity of the mucilage (13.2±1.3 g/g mucilage) makes it an ideal candidate for utilization as viscosifier and stabilizer of suspensions and surfactant-free emulsions. Adult and paediatric paracetamol suspension formulations with 1%w/v mucilage have exhibited flocculated nature and good stability owing to its high sedimentation volume(F= 0.85-0.98) and good redispersibility. Sunflower oil emulsions prepared with 0.25%w/v mucilage demonstrated emulsion stability index of 105.714 on 5th day and extremely low creaming rate of 0.0004 cm/h thus confirming maximum stability compared to emulsions developed with 0.3-0.5% w/v mucilage.Conclusion: The mucilage isolated from Ocimum basilicum L. seeds may be regarded as a functional biomaterial for pharmaceutical use to ensure quality and stability of liquid dosage forms.
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Francke, Nadine Monika, Frederic Schneider, Knut Baumann, and Heike Bunjes. "Formulation of Cannabidiol in Colloidal Lipid Carriers." Molecules 26, no. 5 (March 8, 2021): 1469. http://dx.doi.org/10.3390/molecules26051469.
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In this study, the general processability of cannabidiol (CBD) in colloidal lipid carriers was investigated. Due to its many pharmacological effects, the pharmaceutical use of this poorly water-soluble drug is currently under intensive research and colloidal lipid emulsions are a well-established formulation option for such lipophilic substances. To obtain a better understanding of the formulability of CBD in lipid emulsions, different aspects of CBD loading and its interaction with the emulsion droplets were investigated. Very high drug loads (>40% related to lipid content) could be achieved in emulsions of medium chain triglycerides, rapeseed oil, soybean oil and trimyristin. The maximum CBD load depended on the type of lipid matrix. CBD loading increased the particle size and the density of the lipid matrix. The loading capacity of a trimyristin emulsion for CBD was superior to that of a suspension of solid lipid nanoparticles based on trimyristin (69% vs. 30% related to the lipid matrix). In addition to its localization within the lipid core of the emulsion droplets, cannabidiol was associated with the droplet interface to a remarkable extent. According to a stress test, CBD destabilized the emulsions, with phospholipid-stabilized emulsions being more stable than poloxamer-stabilized ones. Furthermore, it was possible to produce emulsions with pure CBD as the dispersed phase, since CBD demonstrated such a pronounced supercooling tendency that it did not recrystallize, even if cooled to −60 °C.
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Arriagada, Francisco, Catalina Ugarte, Germán Günther, María Angélica Larraín, Víctor Guarnizo-Herrero, Santi Nonell, and Javier Morales. "Carminic Acid Linked to Silica Nanoparticles as Pigment/Antioxidant Bifunctional Excipient for Pharmaceutical Emulsions." Pharmaceutics 12, no. 4 (April 19, 2020): 376. http://dx.doi.org/10.3390/pharmaceutics12040376.
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The incorporation of pigments and natural polyphenols into inorganic matrices, resulting in a hybrid material that improves the resistance and chemical stability of the pigments and the antioxidant capacity of the materials, has been of great interest to the pharmaceutical, chemical and food industries. The aim of this work was to prepare and characterize a bifunctional pigment–antioxidant nanomaterial-based carminic acid-decorated solid core-mesoporous shell silica nanoparticles, evaluating its properties as a pigment, its antioxidant capacity and its properties as a chemical stabilizer of emulsions. The chemical stability of oil-in-water (O/W) Pickering emulsions was evaluated determining the stability of vitamin E solubilized in the oil phase. Carminic acid was attached through the action of coupling ethylcarbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) agents, and the resulting spherical and homogeneous nanoparticles showed a diameter close to 175 nm. A notorious change of emulsion color was observed by the addition of the nanomaterial. Emulsions showed an attractive pink color, and when the pH was adjusted to pH 3 and pH 9, a change in color was observed, analogous to carminic acid in solution. The nanomaterial incorporation also improved chemical stability, decreasing vitamin E consumption to 9.26% of the initial value, demonstrating an important antioxidant effect of the developed nanomaterial.
Dissertations / Theses on the topic "Pharmaceutical emulsions"
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Corswant, Christian von. "Lecithin-based microemulsions for pharmaceutical use phase behavior and solution structure /." Lund : Lund University, 1998. http://catalog.hathitrust.org/api/volumes/oclc/68945035.html.
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Khalil, Enam A. S. A. "A thermodynamic study of binary and ternary mixtures of some alkanes and alkanols." Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328889.
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Johnson, Olufunmilayo Lily. "The formulation of bio-compatible perfluorocarbon emulsions." Thesis, University of Nottingham, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315115.
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Pi, i. Boleda Berta. "Desenvolupament i recerca de formulacions per a vacunes veterinàries." Doctoral thesis, Universitat de Barcelona, 2019. http://hdl.handle.net/10803/668481.
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INTRODUCCIÓ: Aquesta tesi doctoral està inclosa dins del Pla de Doctorats Industrials de la Generalitat de Catalunya i s’ha realitzat conjuntament entre la Universitat de Barcelona i una empresa veterinària privada: Laboratoris Hipra, S.A.
OBJECTIUS: L’objectiu principal d’aquesta tesi ha estat obtenir emulsions estables, amb poder adjuvant i compatibles amb antígens per a la formulació de vacunes veterinàries.
MATERIALS I MÈTODES: Com que les emulsions són composicions afectades per múltiples factors, tots els experiments s’han plantejat mitjançant la metodologia del disseny d’experiments.
RESULTATS I DISCUSSIÓ: En la formulació d’emulsions o/w, l’objectiu ha estat trobar un substitut de l’Espessant A per evitar diferències de viscositat en l’emulsió resultant causades per la naturalesa de l’espessant en funció del lot utilitzat. S’ha començat substituint l’Espessant A per espessants sintètics sense modificar cap més factor de la formulació de partida, però no ha resultat ser un bon mètode per mantenir l’estabilitat de les emulsions formulades. Seguidament, amb l’assaig de diversos factors alhora, s’han aconseguit les primeres emulsions estables sense Espessant A. A partir d’una d’aquestes emulsions, la qual està composta pels espessants Espessant B i Espessant C, s’han plantejat diversos dissenys per buscar més alternatives d’espessants. Per una banda, s’han buscat més espessants principals per substituir el Espessant B i tenir més alternatives possibles de l’Espessant A. I per altra banda, com que la Espessant C és un espessant d’origen natural i, igual que l’Espessant A, proporciona diferències de viscositat segons el lot utilitzat, també se li han buscat substituts. Així doncs, s’ha aconseguit substituir la Espessant C per Espessant F i el Espessant D' ha resultat ser un bon espessant principal, mantenint en els dos casos l’estabilitat de les emulsions. A partir de tots els resultats d’estabilitat i viscositat obtinguts i de les preferències de l’empresa sobre els components de la formulació, s’ha obtingut una formulació definitiva composta per Espessant D', Espessant F i amb menys concentració de tensioactius i fase antigènica que la formulació de partida. Un cop optimitzades les concentracions dels espessants, s’ha fet un estudi amb diferents lots dels espessants que ha demostrat diferències significatives en la viscositat de l’emulsió en funció del lot de Espessant F utilitzat. S’ha vist que el motiu d’aquestes diferències és que el Espessant F necessita ser sotmès a un procés d’activació prèviament a la formulació per poder actuar correctament. Després de
repetir l’optimització amb el Espessant F activat i d’adequar el procés de formulació a nivell de producció industrial, s’ha confirmat que la formulació és robusta i no pateix diferències significatives en funció dels lots utilitzats. Per acabar, s’ha elaborat un estudi d’estabilitat durant 12 mesos que ha corroborat la possible substitució de la formulació de partida per la formulació dissenyada.
En la formulació d’emulsions w/o, l’objectiu ha estat substituir una fase oliosa de composició no coneguda per una fase de composició coneguda i senzilla de formular. S’han plantejat nombrosos dissenys per arribar a tenir una emulsió de signe w/o, estable i d’aspecte fluid. El problema ha estat aconseguir el signe d’emulsió desitjat, cosa que s’ha aconseguit disminuint la concentració del tensioactiu hidròfil de les formulacions. Un cop aconseguides algunes emulsions w/o estables, aquestes no han estat robustes ja que la seva repetició no ha donat els mateixos resultats o no s’han pogut formular amb PBS, fet necessari perquè una emulsió sigui compatible també amb antígens. Finalment, s’ha aconseguit una emulsió de signe w/o, aspecte fluid i estable composta per Oli K, Tensioactiu X, Tensioactiu S’ i Estabilitzant M. S’ha elaborat un estudi d’estabilitat durant 6 mesos que ha corroborat la possible substitució de la formulació de partida per la formulació dissenyada.
CONCLUSIONS: S’han obtingut dues formulacions noves en forma d’emulsió per a l’administració de vacunes per via parenteral d’ús veterinari que són repetibles, robustes, compatibles amb antígens i estables durant el període d’estabilitat assajat.INTRODUCTION: This thesis is the result of a collaboration between Universitat de Barcelona and a private company called Laboratoris Hipra, S.A. Veterinary companies suffer serious economic losses because of diseases such as swine fever. In order to prevent and treat them, veterinary industry makes use of vaccines, for example, in emulsion form. The development of emulsions is not an easy task because emulsions may present stability problems and incompatibility with the antigens selected therefor. AIM: To obtain stable and robust emulsions, which are compatible with the selected antigens. On the one hand, the first specific aim is to replace the natural thickener thickener A present in a commercial o/w emulsion, to avoid viscosity variability depending on thickener batches. On the other hand, the second specific aim is to replace the oil phase present in a commercial w/o vaccine of an unknown composition by a new oil phase. EXPERIMENTAL METHODS: Since emulsions are multifactorial systems, all the trials were planned using experimental design methodology. RESULTS AND DISCUSSION: Regarding the o/w emulsion aim, the substitution of Thickener A by other thickeners was unsuccessfully tested. After many different tests, a stable emulsion comprising Thickener D' and Thickener F as thickeners was obtained. However, this formulation presented variability depending on the batch of Espessant F. This problem was solved by a previous activation of Thickener F. Finally, the definitive formulation with activated Thickener F passed correctly the toxicity test and stability test up to 12 months. Secondly, to develop a w/o emulsion with low viscosity and stable more than 24 hours was a though process. But finally, as a result of many trials combining different oils and surfactants, a formulation comprising ethyl oleate, Span® 80 and Kolliphor® ELP showed positive results regarding stability and viscosity up to 6 months. CONCLUSIONS: Two new emulsions were developed suitable to replace commercial vaccines keeping substantially their initial features such as viscosity, stability and toxicity.
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Sosa, Díaz Lilian Elisa. "Elaboración de formulaciones nanoestructuradas de Anfotericina B para el tratamiento de la Candidiasis, Aspergilosis y Leishmaniosis cutánea." Doctoral thesis, Universitat de Barcelona, 2018. http://hdl.handle.net/10803/665551.
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La piel constituye una de las primeras líneas de defensa de nuestro organismo y, como tal, puede sufrir la agresión de numerosos microorganismos y parásitos. Entre estas patologías cabe mencionar las micosis y la leishmaniosis que pueden tratarse con una variedad de fármacos presentados bajo diferentes formas farmacéuticas diseñadas para las vías de administración correspondientes, siendo las vías más habituales la cutánea, oral y parenteral.
Para el tratamiento de afecciones de la piel y sus anejos, la vía cutánea en principio es la de elección, sin embargo, en algunos casos no aporta los resultados terapéuticos esperados, frecuentemente debido a una escasa penetración y/o retención del fármaco a nivel dérmico. Esta falta de eficacia podría paliarse con el uso de vehículos tales como nanoemulsiones e hidrogeles termorreversibles, dando lugar a nuevas formulaciones que podrían usarse como alternativa a los medicamentos de administración oral o parenteral para el tratamiento de patologías cutáneas.
La Anfotericina B podría ser un buen candidato, dado su potencial nefrotóxico por vía oral y la ausencia en Europa de medicamentos con este principio activo para su administración cutánea.
Si estas nuevas formulaciones fueran viables, supondrían una buena alternativa, dado que en principio se reducirían considerablemente los posibles efectos indeseables del fármaco. Además, comparado con los inyectables, presentarían el beneficio de una administración no invasiva e indolora.
Para el desarrollo de la Tesis se ha realizado un amplio estudio bibliográfico preliminar que viene sintetizado en el capítulo 1 de la memoria. Seguidamente, en el capítulo 2, se exponen los objetivos y plan de trabajo establecido. Los demás capítulos tratan de la parte experimental con sus conclusiones finales.The skin constitutes one of the first lines of defense of our organism and, as such, it can suffer the aggression of many microorganisms and parasites. These pathologies include the mycosis and leishmaniosis that can be treated with a variety of drugs presented under different pharmaceutical forms designed for the corresponding routes of administration, the most common oral, cutaneous and parenteral pathways. For the treatment of skin conditions and their annexes, the skin route in principle is the one of choice, however, in some cases it does not provide the expected therapeutic results, often due to poor penetration and / or retention of the drug at the dermal level. This lack of efficiency could be mitigated by the use of vehicles such as nanoemulsions and thermorreversible hydrogels, giving rise to new formulations that could be used as an alternative to oral or parenteral administration medications for the treatment of cutaneous pathologies. Amphotericin B may be a good candidate, given its oral nephrotoxic potential and the absence in Europe of medications with this active ingredient for its skin administration. If these new formulations were viable, they would be a good alternative, since in principle the potential undesirable effects of the drug would be considerably reduced. In addition, compared with injectables, they would present the benefit of non-invasive and painless administration. For the development of the Thesis, a comprehensive preliminary bibliography study has been carried out which is summarized in Chapter 1 of the report. Next, in Chapter 2, the objectives and established work plan are set out. The other chapters deal with the experimental part with its final conclusions.
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Rosa, Maria Thereza de Moraes Gomes 1986. "Aplicação e potencial das tecnologias de micronização e emulsificação para o processamento de produtos alimentícios e farmacêuticos = Applications and potential of micronization and emulsification technologies in food and pharmaceutical processing." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254914.
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Orientadores: Maria Angela de Almeida Meireles Petenate, Diego Tresinari dos SantosTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: O presente trabalho de doutorado está dividido em dois temas principais, um sobre o uso da tecnologia supercrítica para a formação de partículas e outro sobre o uso do ultrassom para a formulação de emulsões. A revisão da literatura sobre o estado da arte do emprego do CO2 supercrítico para formação de micro e nanopartículas e encapsulação mostrou as potencialidades do uso desta tecnologia. A unidade usada para os experimentos de micronização via tecnologia supercrítica foi desenvolvida pelo grupo de pesquisa e validada utilizando uma substância modelo, o sal de ibuprofeno sódico. Esse fármaco foi selecionado devido às informações sobre o sistema CO2-Ibuprofeno encontradas na literatura. O efeito das condições operacionais (temperatura, pressão, vazão da solução, vazão do CO2, tipo de injetor e concentração de ibuprofeno sódico na solução etanólica) no rendimento de precipitação, teor de solvente residual, morfologia das partículas e consumo energético por unidade de produto processado foi investigado utilizando o método split-plot. Sal de ibuprofeno sódico foi micronizado com sucesso via Antissolvente Supercrítico (SAS) utilizando a unidade construída. A vazão de CO2 influenciou estatisticamente no rendimento de precipitação, enquanto que, não houve influência das condições operacionais no teor de solvente residual das partículas micronizadas. Com a apropriada seleção das condições operacionais, foi possível a obtenção de partículas de ibuprofeno sódico com morfologia de folha, sendo ideal para os processos de compressão do fármaco, com baixo teor de solvente residual e alto rendimento de precipitação. Neste trabalho também foi explorado o uso do ultrassom para a formulação de emulsões, contendo extrato rico em 'delta'-tocotrienol, com o intuito de aumentar o valor agregado deste extrato obtido das sementes de urucum por extração supercrítica com dióxido de carbono. As sementes de urucum já são valiosas pela característica de produzir pigmentos, a bixina e a norbixina. Contudo, essas sementes também vêm adquirindo notoriedade por conter outras substâncias de importância para a saúde do homem, como tocoferóis, tocotrienóis e geranil geraniol. Devido à importância desses compostos bioativos, que apresentam propriedades antioxidade, hidratante e fotoprotetora, este estudo visou o desenvolvimento de métodos para formação de emulsões permitindo a proteção desses compostos instáveis às condições adversas, aumentando assim o valor agregado dos extratos obtidos das sementes de urucum. Extrato de raiz de ginseng brasileiro, rico em saponinas, foi utilizado como biossurfactante. Adicionalmente, emulsões foram obtidas utilizando um homogeneizador tipo dispersor de fase múltipla na mesma densidade energética que foi aplicada no ultrassom. A influência do processo de emulsificação, densidade energética, concentração do biosurfactante, tipo de óleo e de biosurfactante no tamanho de gota e estabilidade da emulsão foi investigada. Os resultados indicaram que o extrato rico em saponinas pode ser uma boa opção para formulação de emulsões para aplicação em produtos alimentícios. Miniemulsões, com tamanho de gota variando entre 0,35 e 0,83 µm, foram obtidas, sendo que os menores tamanhos de gota foram observados empregando o extrato de raiz de ginseng e o ultrassom. O processo de emulsificação influenciou estatisticamente a estabilidade das emulsões
Abstract: The presented doctoral work is divided into two main themes under which one is about the use of supercritical technology for particle formation and the another one about the use of ultrasound for emulsion formulation. A literature review about the state of the art in using supercritical CO2 for micro and nanoparticles formation and encapsulation showed the potential of this technology. A homemade experimental apparatuses constructed by our research group and used for micro and nanoparticles formation has been validated using a model substance, the ibuprofen sodium salt. This drug was selected due to the literature information of the CO2-Ibuprofen system. The effect of operational conditions (temperature, pressure, CO2 flow rate, solution flow rate, injector and concentration of ibuprofen sodium in the ethanol solution) on the precipitation yield, energy consumption per unit of manufactured product, residual solvent content and particle morphology have been investigated using split-plot designs. Ibuprofen sodium salt was successfully micronized by Antisolvent Supercritical (SAS) using the constructed unit. The CO2 flow rate influenced the precipitation yield at statistically significant levels meanwhile none operating parameters did influence the residual solvent content in the micronized particles. Selecting appropriate process conditions, it has been shown to facilitate the production of homogeneous sheet-like microparticles of ibuprofen particles, the best for tableting purposes, with low residual solvent and high precipitation yield. In this work, the use of ultrasound has been also explored for fabricating microemulsion of 'delta'-tocotrienol-rich oil in order to add value to these extracts obtained from annatto seeds using supercritical extraction (SFE). The main pigments of annatto seeds are bixin and norbixin, wich are valuable natural colorants. However, these seeds have acquired notoriety by containing other important substances for human health, such as tocopherols, tocotrienols and geranylgeraniol. Due to the bioactive compounds importance, which have moisturizers, sunscreens and antioxidant properties, this study aimed to develop methods for emulsion formulation enabling the protection of these unstable compounds to adverse conditions, thus increasing the value of extracts from annatto seeds. Saponin-rich extract from Brazilian ginseng roots was used as biosurfactant. Additionally, emulsion was generated through mechanical stirring by dispax Reactor at the same energy density than ultrasound. The influence of the emulsification process, energy density, oil type, biosurfactant type and biosurfactant concentration on the size and stability of the resulting droplets was investigated. The results indicated that saponin-rich extract might be an attractive biosurfactant choice for emulsion formulations for use in food and beverage products. Mini-emulsions were obtained in this work; their droplet sizes ranged from 0.35 to 0.83 µm, saponin-rich extract and ultrasound gave the smallest droplet size. The emulsification process significantly affected the emulsion stability values
Doutorado
Engenharia de Alimentos
Doutora em Engenharia de Alimentos
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Serikaku, Daniela. "Avaliação in vitro da liberação, penetração e retenção cutâneas de ciclopirox olamina em formulações de uso tópico por um processo validado." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/9/9139/tde-05122017-142258/.
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Para que um produto de aplicação tópica apresente o efeito terapêutico é necessário que o fármaco seja liberado de seu veículo e atravesse a barreira do estrato córneo, atingindo seus sítios de ação nas camadas da pele nas quais o efeito é esperado. Os estudos de penetração cutânea in vitro, utilizando células de difusão de Franz modificadas, podem fornecer resultados úteis quanto à eficácia do produto. As dermatofitoses são micoses superficiais. São manifestações crônicas e resistentes ao tratamento, fato que se explica não só em decorrência da própria natureza destas afecções como também devido à baixa penetração de fármacos antimicóticos na pele. Dentre os antifúngicos disponíveis na terapêutica, ciclopirox olamina é uma substância que tem demonstrado elevada eficácia no tratamento de dermatofitoses. O presente trabalho teve como objetivo desenvolver formulações de uso tópico contendo 0,5% de ciclopirox olamina e avaliar a performance dessas formulações. Foi possível obter formulações estáveis fisicamente, contendo promotores de penetração cutânea. O sistema de amostragem automática utilizado para realização dos experimentos foi qualificado e apresentou-se em condições adequadas.In order to present the pharmacological effect, a topical product must release the pharmaceutical active ingredient from its vehicle and this active must pass through the stratum corneum barrier, reaching the target layer of the skin, where its effect is desired. In vitro skin penetration studies, using modified diffusion Franz cells, can provide useful results regarding the product efficacy. Dermatophytosis is superficial mycosis resistant to treatment due to the disease nature and also to the low penetration profile of the antifungals into the skin. Among the antifungals available in the therapeutic arsenal, ciclopirox olamine has demonstrated a high efficacy in the treatment of dermatophytosis. The objectives of the present work were to develop topical formulations containing 0,5% of ciclopirox olamine and evaluate their performance. It was possible to obtain physically stable formulae, containing skin penetration enhancers. The automatic sampling system used in the experiments was qualified, showing adequate performance.
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Sharma, Anita. "Water-in Water (W/W) Emulsion Drug Delivery Systems." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1365954454.
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Mirzamani, Marzieh. "Investigating Colloidal Domains of Emulsion- and Gel-Type Formulations Using Neutron Scattering Techniques." University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1623167085524348.
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Zhao, Xiaoning. "Synthesis and applications of functional magnetic polymer beads; synthesis and mass spectrometry analysis of model peptides." Scholarly Commons, 2012. https://scholarlycommons.pacific.edu/uop_etds/156.
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The first part of the thesis describes the synthesis and application of functional magnetic polymer beads. The traditional suspension polymerization approach was used to synthesize polystyrene-iron oxide (Fe 3 O 4 ) based magnetic beads. The beads were coupled to different surface functional groups. The Fe 3 O 4 particles were encapsulated into a polystyrene shell. The surface functional groups were generated by graft-polymerization with functional monomers. The average size of the beads was in the range of 100-500 μm. Chemical tests showed that the beads were stable in strong acid, strong base and polar solvent. The beads had a fast response to an external magnetic field. A self-emulsion-polymerization approach was developed to synthesize smaller magnetic beads with the - OH groups on the surface. A modified approach based on traditional suspension-polymerization was developed to synthesize acid-durable beads with more Fe 3 O 4 encapsulated inside the beads. A novel emulsion-suspension polymerization method was successfully developed to synthesize much smaller magnetic beads ( A new peptide synthesis approach was developed using functional magnetic beads as the resin for solid phase synthesis. In this application, synthesized magnetic beads were further modified by a two-step reaction. The amino group was anchored onto the surface of these beads, followed by coupling with the Rink amide linker. The resulting beads were used as the resin to synthesize several model peptides. The peptides were successfully synthesized, and the sequences were confirmed by mass spectrometry analysis. The yields of the peptides were comparable to those obtained from commercial Rink amide resin. The second part of the thesis describes the synthesis and mass spectrometry analysis of two series of model peptides. One series has the linear (non-cyclic) structure, A n K, KA n , P n K, and AcA n K. The other series contains cyclic peptides, c-Ac-DAKAK and c-Ac-DADapAK. All peptides were synthesized using solid phase peptide synthesis. The relative proton affinities of the model peptides were measured using the collision induced dissociation experiments using a triple quadrupole mass spectrometer. It was found that the effective proton affinity of a cyclic peptide was significantly reduced compared to a linear analogue. The reduced proton affinity implies an increased lipophilicity of the peptide.
Books on the topic "Pharmaceutical emulsions"
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Sarker, Dipak K. Pharmaceutical Emulsions. Chichester, UK: John Wiley & Sons, Ltd, 2013. http://dx.doi.org/10.1002/9781118648384.
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Françoise, Nielloud, and Marti-Mestres Gilberte, eds. Pharmaceutical emulsions and suspensions. New York: Marcel Dekker, Inc., 2000.
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Nielloud, Françoise, and Gilberte Marti-Mestres. Pharmaceutical Emulsions and Suspensions. CRC Press, 2000. http://dx.doi.org/10.1201/b14005.
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Sarker, Dipak Kumar. Pharmaceutical Emulsions: A Drug Developer's Toolbag. Wiley & Sons, Incorporated, John, 2013.
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Sarker, Dipak Kumar. Pharmaceutical Emulsions: A Drug Developer's Toolbag. Wiley & Sons, Incorporated, John, 2013.
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Pharmaceutical Emulsions and Suspensions (Drugs and the Pharmaceutical Sciences). CRC, 2000.
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(Editor), Herbert Lieberman, Martin Rieger (Editor), and Gilbert S. Banker (Editor), eds. Pharmaceutical Dosage Forms. 2nd ed. Informa Healthcare, 1996.
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Nielloud, Francoise, and Gilberte Marti-Mestres. Pharmaceutical Emulsions and Suspensions: Second Edition, Revised and Expanded (Drugs and the Pharmaceutical Sciences). 2nd ed. Informa Healthcare, 2010.
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1920-, Lieberman Herbert A., Rieger Martin M. 1920-, and Banker Gilbert S. 1931-, eds. Pharmaceutical dosage forms--disperse systems. New York: Dekker, 1988.
Find full textBook chapters on the topic "Pharmaceutical emulsions"
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Pacek, Andrzej W. "Emulsions." In Pharmaceutical Blending and Mixing, 183–232. Chichester, UK: John Wiley & Sons, Ltd, 2015. http://dx.doi.org/10.1002/9781118682692.ch9.
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Junginger, H. E. "Pharmaceutical Emulsions and Creams." In Emulsions — A Fundamental and Practical Approach, 189–205. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2460-7_13.
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Brunaugh, Ashlee D., Hugh D. C. Smyth, and Robert O. Williams III. "Disperse Systems: Emulsions." In AAPS Introductions in the Pharmaceutical Sciences, 111–21. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-31745-4_7.
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Shively, Merrick L. "Multiple Emulsions for the Delivery of Proteins." In Pharmaceutical Biotechnology, 199–211. Boston, MA: Springer US, 2002. http://dx.doi.org/10.1007/0-306-46803-4_7.
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"Pharmaceutical Emulsions." In Pharmaceutical Dosage Forms and Drug Delivery, 167–76. CRC Press, 2007. http://dx.doi.org/10.1201/b13576-19.
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"Implants." In Pharmaceutical Emulsions, 109–10. Chichester, UK: John Wiley & Sons, Ltd, 2013. http://dx.doi.org/10.1002/9781118648384.ch10.
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"De NovoScience, Sustainable Novel Products and Platform Applications." In Pharmaceutical Emulsions, 111–15. Chichester, UK: John Wiley & Sons, Ltd, 2013. http://dx.doi.org/10.1002/9781118648384.ch11.
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"Physicochemical Properties." In Pharmaceutical Emulsions, 119–36. Chichester, UK: John Wiley & Sons, Ltd, 2013. http://dx.doi.org/10.1002/9781118648384.ch12.
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"Sizing and Microscopy." In Pharmaceutical Emulsions, 137–39. Chichester, UK: John Wiley & Sons, Ltd, 2013. http://dx.doi.org/10.1002/9781118648384.ch13.
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"Rheology, Texture, Consistency and Spreadability." In Pharmaceutical Emulsions, 141–48. Chichester, UK: John Wiley & Sons, Ltd, 2013. http://dx.doi.org/10.1002/9781118648384.ch14.
Full textConference papers on the topic "Pharmaceutical emulsions"
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Raikar, Neha B., Surita R. Bhatia, Michael F. Malone, and Michael A. Henson. "Applications of population balance equation modeling to pharmaceutical emulsions." In 2009 IEEE 35th Annual Northeast Bioengineering Conference. IEEE, 2009. http://dx.doi.org/10.1109/nebc.2009.4967810.
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Unnikrishnan, Saritha, John Donovan, Russell Macpherson, and David Tormey. "Machine vision for the quality assessment of emulsions in pharmaceutical processing." In 2018 4th International Conference on Universal Village (UV). IEEE, 2018. http://dx.doi.org/10.1109/uv.2018.8642158.
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Anicescu, Maria-Cristina, Cristina-Elena Dinu-Pirvu, Mihaela Violeta Ghica, Valentina Anuta, Razvan Mihai Prisada, Marina-Theodora Talianu, and Lacramioara Popa. "Preliminary analysis of emulsion-based formulations containing pumpkin seed oil and hemp seed oil for internal use." In The 8th International Conference on Advanced Materials and Systems. INCDTP - Leather and Footwear Research Institute (ICPI), Bucharest, Romania, 2020. http://dx.doi.org/10.24264/icams-2020.ii.1.
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With a long tradition in pharmaceutical design, emulsions are functional formulations that can maintain their adaptive power connected with the new formulation requirements. Hence, this study proposed preliminary assays concerning the obtaining of natural emulsions for oral administration, incorporating pumpkin seed oil and hemp seed oil as oil phases, with lecithin as emulsifying agent. Using emulsification method, O/W and W/O emulsions were prepared and characterized from a stability point of view considering organoleptic parameters, conductivity properties followed by an extensive superficial analysis by fitting two different goniometric approaches like contact angle and pendant drop models. The emulsions obtained were stable, homogeneous, their properties being reflected by composition. Conductivity values confirmed the type of emulsions, completing their profile. Superficial analysis revealed that lecithin can sustain a proper stability due to a variation of surface tension values around 25 mN/m. The mean contact angle values ranging between 31.87±0.51° and 44.01±5.48° defined an adequate wettability, being correlated with the internal structure. To conclude, this preliminary study offered important data concerning the stability of some emulsions for oral delivery, accessing natural biocompatible components. On this way, it can be created multifunctional systems with nutritional value, but also special vehicles designed for drug delivery.
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Lu, Li, Rebecca M. Irwin, Jeffrey W. Schertzer, and Paul R. Chiarot. "Particulate and Emulsion Sorting Using Microfluidics." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-38298.
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We report on a microfluidic device capable of sorting nanoscale particulates and water-in-oil emulsions at high-throughput. The device is passive, relying solely on hydrodynamic forces and the emulsion mass to achieve separation. We use the microfluidic device to deliver surfactants and lipids to the emulsion surface. This is achieved by immersing the emulsions in a fluid stream with a high concentration of the nano-particulates. The particulates assemble on the surface of the emulsions as they are transported along the stream. The emulsions are then transferred (i.e. separated) into a second fluid stream that is devoid of surrounding material. The performance of the device is evaluated for a range of flow rates, nano-particulate concentrations, and emulsion sizes. We report separation efficiencies that exceed current technologies over a wide range of flow rates. The microfluidic device can be used to produce delivery vehicles for pharmaceuticals and models for membrane biology studies.
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Shahidi, Seyedehsan, Charles R. Koch, and Subir Bhattacharjee. "A Milli-Fluidic Device for Electrical Impedance Spectroscopy of Complex Liquids." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-65293.
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Rapid characterization of complex liquids such as solutions, mixtures, dispersions, and emulsions is useful in a variety of industrial applications ranging from cosmetics, pharmaceuticals, to petroleum production. An electrical impedance spectroscopy (EIS) based technique for rapidly determining the characteristics of liquid-liquid mixtures is presented in this study. A milli-fluidic liquid film impedance measurement cell is developed employing 3D printing technology. The cell is tested using glycerol-water mixtures followed by castor oil in water emulsion samples. Frequency response analysis and equivalent circuit modeling are performed on each sample to quantify the emulsion properties in the form of equivalent capacitance and resistance. The developed technique provides an inexpensive and disposable, yet robust experimental platform for applying EIS to investigation and rapid estimation of different properties of oil-water emulsions.
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Almeida, Ekmagage Don N., Leela Rakesh, Stanley Hirschi, and Anja Mueller. "Solution Rheology of Saline and Polysaccharide Systems." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-15906.
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The problem of the characterization of the solution properties of water soluble polymers is long-standing. These polymers tend to form aggregated supramolecular gels that are resistant to molecular dispersion. These materials are being widely used in a variety of industrial applications. Their principle functions are as rheological modifiers, where they thicken or gel solutions in products such as hair-care, detergents, air fresheners and foods; as flocculants for particle separation as applied to water clarification, sewage, and effluent treatment, and as stabilizers to control the properties of concentrated suspension and emulsions, for example in paints, pesticides, dyes, and pharmaceutical industries. Therefore it is important to understand their rheological properties under various operating conditions such as stress, strain, temperature etc, which will induce gelation. The rheological properties of starch gels of high concentration (up to 86% starch) have been investigated before [1]. In this paper we have investigated experimentally the shear viscosity and viscoelasticity properties of saline and polysaccharide suspensions at various low concentrations and pH at different temperatures using controlled stress and strain rheometers (Vilastic-3 and AR 2000). The data were then fitted with the power law and Cross model for low and higher concentrations respectively. The present results show that the viscosity/elasticity does not significantly change for low concentrations at different pH values. The maximum viscosity/elasticity was obtained around pH 5-7.4 at higher concentrations.
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Neves, Marcos A., Isao Kobayashi, and Mitsutoshi Nakajima. "Scaling-Up Microchannel Emulsification Foreseeing Novel Bioactives Delivery Systems." In ASME 2013 11th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/icnmm2013-73116.
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In the recent years, emulsification technologies that generate droplets individually have attracted a great deal attention in various fields, e.g., for chemicals, cosmetics, foods, and pharmaceuticals. Such drop-by-drop emulsification technologies include membrane emulsification using microporous membranes and microchannel (MC) emulsification, among others. The authors developed MC emulsification chips, consisting of parallel microgrooves or compactly arranged straight through-holes. Using this MC emulsification technique, the authors have evaluated the formulation a two-phase system consisting of size-controlled O/W emulsions loaded with bioactive molecules, such as β-carotene or γ-oryzanol, PUFAs or polyphenols. The MC emulsification process enabled the production of β-carotene-loaded O/W emulsions with average droplet size (dav) of 27.6 μm and coefficient of variation (CV) of 2.3% and γ-oryzanol-loaded droplets with dav of 28.8 μm and CV of 3.8%. The highly monodisperse O/W emulsions were physically stable during up 4 months storage in darkness at 5 °C. In addition, we investigated the formation characteristics of O/W emulsion droplets in the presence of electrolyte by MC emulsification using differently charged surfactants. Droplet formation was conducted by pressurizing a dispersed phase (refined soybean oil) through the MC silicon chip into a continuous phase containing 1.0 wt% of sodium dodecyl sulfate (SDS) or polyoxyethylene (20) sorbitan monolaurate (Tween 20), and an electrolyte (NaCl) (0–1.0 mol/L). Monodisperse O/W emulsions with an dav of 26 μm and a CV below 5% were produced when the NaCl concentration was lower than a threshold level that is 0.3 mol/L for SDS and 0.5 mol/L for Tween 20. The authors also developed a large MC emulsification device including a newly designed asymmetric MC array chip to realize the mass production of uniformly sized droplets on a liter per hour scale, so that satisfying the minimum droplet productivity needed for industrial-scale production. The large MC emulsification device has a potential droplet productivity exceeding several tons per year, which could satisfy a minimum industrial-scale production of monodisperse microdispersions containing emulsion droplets, microparticles, and microcapsules loaded with bioactive compounds. Such systems have as continuously increasing potential application in the formulation of functional foods, providing a good opportunity to improve the solubility of bioactive compounds, so that increasing their bioavailability.
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Kobayashi, Isao, and Mitsutoshi Nakajima. "Micro/Nanochannel Emulsification for Generating Monosize Droplets." In ASME 2012 Third International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/mnhmt2012-75238.
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Emulsification is an important process in various fields including foods, pharmaceuticals, cosmetics, and chemicals. Emulsification operation is commonly conducted using conventional emulsification devices, such as high-speed blenders, colloid mills, high-pressure homogenizers, and ultrasonic homogenizers. However, these emulsification devices result in the production of polydisperse emulsions with wide droplet size distributions and poor controllability in droplet size and its distribution. In contrast, monodisperse emulsions consisting of monosize droplets have received a great deal of attentions over the past decade due to their high-tech applications, e.g., monosize microparticles as spacers for electronic devices and monosize micro-carriers for drug delivery systems (DDS). Our group proposed microchannel (MC) emulsification as a promising technique to produce monodisperse emulsions in the mid 1990s. Micro/Nanochannel (MNC) emulsification enables generating monosize droplets with the smallest coefficient of variation (CV) of below 5% using MC and nanochannel (NC) arrays of unique geometry. The resultant droplet size, which ranged from 0.5 to 200 μm, can be precisely controlled by channel geometry. Droplet generation for MNC emulsification is very mild and does not require any external shear stress; a dispersed phase that passed through channels is transformed spontaneously into monosize droplets inside a continuous-phase domain. The aim of this paper is to present recent developments in MNC emulsification chips, particularly focusing on asymmetric straight-through MC arrays for large-scale production of monodisperse emulsions. Asymmetric straight-through MC array chips were fabricated using a silicon-on-insulator wafer. Numerous asymmetric straight-through MCs each consisting of a microslot and a narrow MC were positioned in the central region of the chip. Monosize droplets were stably generated via asymmetric straight-through MCs at high production rates. Below a critical droplet production rate, monosize droplets were generated via asymmetric straight-through MCs, with droplet size and size distribution independent of the droplet productivity. The use of a large asymmetric straight-through MC array chip achieved the mass production of monosize tetradecane oil droplets at ∼1 L/h. The simulation results using CFD (computational fluid dynamics) agreed well with the experimental results and provided useful information, such as the movement of the oil-water interface during droplet generation. Monosize submicron droplets were also obtained using NC emulsification chips made of single-crystal silicon.
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Zammouri, Amel, N. Boudhrioua Mihoubi, and N. Kechaou. "Comparison between bubbling and turbulent regime for the simulation of batch pharmaceutical powders fluidized bed drying." In 21st International Drying Symposium. Valencia: Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/ids2018.2018.7703.
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The two-phase theory has been frequently used to model fluidised bed drying. At high air velocities, a transition from the bubbling regime to the turbulent regime may occur. In this work, we compare a bubbling model and a turbulent model for the simulation of a two pharmaceutical powders drying in a pilot plant and an industrial plant fluidised bed. The bubbling model was based on a discrete variable bubble size. Heat and mass transfer coefficients were based on the Kunii and Levenspiel correlation [1]. Flow regime was supposed to be completely mixed for the emulsion phase. For the turbulent model, the bubble size is not anymore discrete but continuous and bubble phase is less distinguishable than in the bubbling regime. Heat and mass transfer were those proposed by Foka[2]. In addition, the freeboard section was considered since high entrainment is specific of this regime. Gas backmixing was taken into account by considering a plug flow with axial dispersion for the interstitial gas flow. The bubble phase being dilute, was modeled by a plug flow. A plug flow was also considered for the freeboard gas. The solid phase was supposed to be completely mixed. The bubbling regime simulation gave good agreement with experiment in the case of the pilot plant experiment, while the turbulent model better simulated the industrial scale experiment. Key words: batch fluidized bed, pharmaceutical powder, drying, modeling, bubbling, turbulent
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Wang, Yechun, and Panagiotis Dimitrakopoulos. "Computational Studies of Interfacial Dynamics in Microfluidics via a 3D Spectral Boundary Integral Algorithm." In ASME 2009 Second International Conference on Micro/Nanoscale Heat and Mass Transfer. ASMEDC, 2009. http://dx.doi.org/10.1115/mnhmt2009-18556.
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Interfacial dynamics in micron-sized geometries is getting more attention as technologies evolve towards small scales. In pharmaceutical and biochemical applications, fluid droplets moving in microfluidic channels are utilized as “micro-reactors” to precisely control the reaction rate and enhance the mixing efficiency of the reagents. In emulsion generations, low polydispersity of droplets is achieved by the “passive” fission, fusion and sorting of droplets in microfluidic channels. In nanolithography, a micron/nano sized fluid bridge forms between the substrate and the depositing tip. The ability to numerically simulate in a fast and accurate manner the behavior of a small volume of fluid in microfluidic systems is thus demanded. We utilize a 3D Spectral Boundary Element algorithm for interfacial dynamics in microfluidics that exploits all the benefits of the spectral methods (i.e. exponential convergence and numerical stability) but it is not affected by the disadvantage of the spectral methods used in volume discretization to create denser systems. We consider the deformation and migration of droplets in a square microfluidic channel. We investigate the behavior for a single droplet. The effects of droplet size, flow rate and viscosity ratio will be presented.