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Emulsion Solvent Evaporation Method (emulsion + solvent_evaporation_method)
Selected AbstractsMicroencapsulation of rosmarinic acid using polycaprolactone and various surfactantsINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 3 2010H.-J. Kim Synopsis Rosmarinic acid (RA) has a number of interesting biological activities, e.g. anti-viral, anti-bacterial, anti-inflammatory and antioxidant. The antioxidant activity of RA is stronger than that of vitamin E. Despite its strong antioxidant activity, it was limited to use in cosmetics because of the low water solubility, discolouration and chemical instability. The purpose of this study was to prepare RA-loaded polycaprolactone (PCL) microspheres using emulsion solvent evaporation method and characterize them with different surfactants used in the formation process. Finally, long-term stability of RA was evaluated in the cosmetic formulation. As a result, PCL microspheres were found to be spherical in shape, with zwitterionic surfactant-PCL particles being the smallest size distribution and highest entrapment efficiency of RA. Emulsions containing RA-loaded PCL microspheres showed a better long-term stability of the RA compared with those containing only RA. These results suggest that RA may be stably and efficiently encapsulated into polycaprolactone microspheres. Résumé Micro encapsulation d'acide rosmarinique utilisant la polycaprolactone et divers surfactants L'acide rosmarinique a un certain nombre d'activités biologiques intéressantes, par exemple antivirales, antibactériennes, anti-inflammatoires et antioxydantes. L'activité antioxydante de l'acide rosmarinique est plus puissante que celle de la vitamine E. Malgré sa forte activité antioxydante, son usage en cosmétique est limité en raison de sa faible solubilité dans l'eau, sa décoloration et son instabilité chimique. Le but de cette étude était de préparer des microsphères de PCL chargées d'acide rosmarinique par la méthode d'émulsification par d'évaporation de solvant et de les caractériser selon les différents surfactants utilisés dans le processus de fabrication. Enfin, la stabilitéà long terme de l'acide rosmarinique a étéévaluée dans la formulation cosmétique. Les microsphères PCL ont été trouvé de forme sphérique, avec les surfactants zwitterioniques, les particules PCL offrent une distribution de petites tailles et une efficacité de piégeage en acide rosmarinique la plus élevée. Les émulsions contenant des microsphères PCL chargées d'acide rosmarinique ont montréà long terme une meilleure stabilité en acide rosmarinique que celles contenant l'acide seul. Ces résultats suggèrent que l'acide rosmarinique peut être encapsulé de façon efficace et stable dans des microsphères de polycaprolactone. [source] Preparation, physiochemical characterization, and oral immunogenicity of A,(1,12), A,(29,40), and A,(1,42) loaded PLG microparticles formulationsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 6 2009R. Rajkannan Abstract Alzheimer's disease (AD) is caused by the deposition of ,-amyloid (A,) protein in brain. The current AD immunotherapy aims to prevent A, plaque deposition and enhance its degradation in the brain. In this work, the peptides B-cell epitope A,(1,12), T-cell epitope A,(29,40) and full-length A,(1,42) were loaded separately to the poly (D,L -lactide co-glycolide) (PLG) microparticles by using W/O/W double emulsion solvent evaporation method with entrapment efficacy of 70.46%, 60.93%, and 65.98%, respectively. The prepared A, PLG microparticles were smooth, spherical, individual, and nonporous in nature with diameters ranging from 2 to 12 µm. The cumulative in vitro release profiles of A,(1,12), A,(29,40), and A,(1,42) from PLG microparticles sustained for long periods and progressively reached to 73.89%, 69.29%, and 70.08% by week 15. In vitro degradation studies showed that the PLG microparticles maintained the surface integrity up to week 8 and eroded completely by week 16. Oral immunization of A, peptides loaded microparticles in mice elicited stronger immune response by inducing anti-A, antibodies for prolonged time (24 weeks). The physicochemical characterization and immunogenic potency of A, peptides incorporated PLG microparticles suggest that the microparticles formulation of A, can be a potential oral AD vaccine. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:2027,2039, 2009 [source] Preparation and characterization of quercetin-loaded polymethyl methacrylate microcapsules using a polyol-in-oil-in-polyol emulsion solvent evaporation methodJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 12 2007Dong-Hwan Lee Flavonoids and related compounds exhibit a wide range of useful pharmacological properties but present challenges related to their stability and solubility in commonly available solvents. In this study, polymethyl methacrylate (PMMA) microcapsules were prepared using a novel polyol-in-oil-in-polyol (P/O/P) emulsion solvent evaporation method as a means of stabilizing the flavonoids, using quercetin as a model flavonoid drug. The morphology of the microcapsules was evaluated using a scanning electron microscope, revealing a spherical shape with a smooth surface. The cross-section image of the PMMA microcapsules prepared with an amphiphilic polymer in the inner polyol phase showed that the microcapsule was filled with several submicron microspheres. The mean diameter varied from 1.03 ± 0.12 ,m to 2.39 ± 0.42 ,m, and the encapsulation efficiency ranged from 12.7% to 26.9%. When free quercetin was stored at 42°C, the residual quercetin content gradually decreased to 18% over 28 days as a result of oxidation. However, when encapsulated in PMMA microcapsules with an amphiphilic polymer in the inner polyol phase, the residual quercetin content decreased to just 82%. In-vitro release studies indicated a sustained release pattern throughout the 36-h study. The release kinetics of the microcapsules with an amphiphilic polymer followed a diffusion-controlled mechanism and the microcapsule without amphiphilic polymer followed an anomalous diffusion behaviour. This study suggests that the novel P/O/P emulsion solvent evaporation method can be applied to the encapsulation of flavonoids. [source] Nanoparticle formulation enhances the delivery and activity of a vascular endothelial growth factor antisense oligonucleotide in human retinal pigment epithelial cellsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 9 2003Jithan V. Aukunuru ABSTRACT The objective of this study was to investigate the delivery and activity of a vascular endothelial growth factor (VEGF) antisense oligonucleotide in a human retinal pigment epithelial cell line (ARPE-19) using a biodegradable nanoparticulate delivery system. A 19-mer antisense phosphorothioate oligonucleotide (PS-ODN) complementary to bases 6,24 relative to the translational start site of the VEGF mRNA, a sense PS-ODN and a mismatch PS-ODN were examined for the inhibition of secretion and mRNA expression of VEGF using an enzyme-linked immunosorbent assay and reverse transcription,polymerase chain reaction, respectively. Nanoparticles of the antisense oligonucleotides were formulated using a poly(lactide-co-glycolide) (50:50) copolymer using a double emulsion solvent evaporation method. After preparing nanoparticles, drug loading, encapsulation efficiency and particle size were determined. The cells were exposed to either plain solution of oligonucleotide or nanoparticles of oligonucleotide from Day 3 through Day 6. Alternatively, the cells were incubated with PS-ODNs and lipofectin for 4h on Day 4. In all studies, VEGF secretion and mRNA expression were determined on Day 6. The particle size, drug loading and encapsulation efficiency were 252 nm, 5.5% and 16.5%, respectively. The antisense PS-ODN inhibited VEGF mRNA and protein secretion when delivered using nanoparticles or lipofectin but not in its free form. This was consistent with the ability of nanoparticles and lipofectin to elevate the cellular uptake of the oligonucleotide by 4-fold and 13-fold, respectively. Neither mismatch nor sense oligonucleotides inhibited VEGF secretion. In conclusion, biodegradable nanoparticles enhance cellular delivery of a VEGF antisense oligonucleotide and inhibit VEGF secretion and mRNA expression in a human retinal pigment epithelial cell line. [source] Preparation, characterization and taste-masking properties of polyvinylacetal diethylaminoacetate microspheres containing trimebutineJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 10 2002Yoshimi Hashimoto The objectives of this study were to produce acid soluble, polyvinylacetal diethylaminoacetate (AEA) microspheres containing trimebutine (as maleate), using a water-in-oil-in-water (w/o/w) emulsion solvent evaporation method, to characterize their in-vitro release properties, and to evaluate the taste-masking potential of this formulation in human volunteers. The pH of the external aqueous phase was the critical factor in achieving a high loading efficiency for trimebutine in the microencapsulation process; nearly 90% (w/w) loading efficiency was obtained at above pH 10. Trimebutine was completely released from AEA microspheres within 10 min in a dissolution test at pH 1.2, simulating conditions in the stomach, whereas at pH 6.8, the pH in the mouth, only small quantities of trimebutine were released in the initial 1,2 min. The results of a gustatory sensation test in healthy volunteers confirmed the taste-masking effects of the AEA microspheres. Finally, an attempt was made to encapsulate the salts of other basic drugs (lidocaine, imipramine, desipramine, amitriptyline, promethazine and chlorpheniramine) into AEA microspheres using the w/o/w emulsion evaporation method. The loading efficiencies were ranked in almost inverse proportion with the solubility of the drugs in the external aqueous phase. This study demonstrated the possibility of masking the taste of salts of basic drugs by microencapsulation with AEA using a w/o/w emulsion solvent evaporation method. [source] Biodegradable Polymeric Microcarriers with Controllable Porous Structure for Tissue EngineeringMACROMOLECULAR BIOSCIENCE, Issue 12 2009Xudong Shi Abstract Porous microspheres fabricated by biodegradable polymers show great potential as microcarriers for cell cultivation in tissue engineering. Herein biodegradable poly(DL -lactide) (PLA) was used to fabricate porous microspheres through a modified double emulsion solvent evaporation method. The influence of fabrication parameters, such as the stirring speed of the primary and secondary emulsion, the polymer concentration of the oil phase, and solvent type, as well as the post-hydrolysis treatment of the porous structure of the PLA microspheres are discussed. Good attachment and an active spread of MG-63 cells on the microspheres is observed, which indicates that the PLA microspheres with controllable porous structure are of great potential as cell delivery carriers for tissue engineering. [source] | ||||||||||