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Solvent Evaporation Method (solvent + evaporation_method)
Kinds of Solvent Evaporation Method Selected AbstractsTris(8-hydroxyquinoline-5-sulfonate)aluminum Intercalated Mg,Al Layered Double Hydroxide with Blue Luminescence by Hydrothermal SynthesisADVANCED FUNCTIONAL MATERIALS, Issue 17 2010Shuangde Li Abstract Blue luminescent hybrid materials (DDS,AQS(x%)/LDH) are successfully prepared by co-intercalating tris(8-hydroxyquinoline-5-sulfonate)aluminum anions (AQS3,) and dodecyl sulfonate (DDS,) with different molar ratios into Mg,Al layered double hydroxides (LDHs) by the hydrothermal and solution co-precipitation methods. A film of the material on a quartz substrate is obtained by the solvent evaporation method. The results show the blue luminescence is remarkably different from the pristine Na3AQS, which has cyan luminescence (ca. 450,470 nm vs. 495 nm). Furthermore, the hydrothermal product of DDS,AQS(66.67%)/LDH exhibits optimal luminous intensity and a significantly enhanced fluorescence lifetime. Nuclear magnetic resonance and Fourier-transform infrared spectroscopy indicate that the cyan,blue luminescence transition is due to the isomerization of meridianal to facial AQS via ligand flip caused by a host,guest electrostatic interaction, in combination with the dispersion and pre-intercalation effect of DDS. The hydrothermal conditions can promote a more ordered alignment of the intercalated fac -AQS compared with alignment in the solution state, and the rigid LDHs environment can confine the internal mobility of AQS to keep the facial configuration stable. This stability allows a facile preparation of large amounts of blue luminous powder/film, which is a new type of inorganic,organic hybrid photofunctional material. [source] Microencapsulation 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] Feasibility study of aerosolized prostaglandin E1 microspheres as a noninvasive therapy for pulmonary arterial hypertensionJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 4 2010Vivek Gupta Abstract This study was designed to test the feasibility of polymeric microspheres as an inhalable carrier for prostaglandin E1 (PGE1) for treatment of pulmonary arterial hypertension. Poly(lactic- co -glycolic acid) (PLGA) microspheres were prepared by a double emulsion,solvent evaporation method. Six different microspheric formulations were prepared using two different blends of PLGA (50:50 and 85:15) and varying concentrations of polyvinyl alcohol (PVA) in the external aqueous phase (EAP). The particles were characterized for morphology, size, aerodynamic diameter, entrapment efficiency, release patterns, and metabolic stability. Pulmonary absorption was studied in a rat model, and safety of the formulations was evaluated by measuring cytotoxicity in Calu-3 cells and assessing injury markers in bronchoalveolar lavage (BAL) fluid. Both actual particle size and aerodynamic diameter of the formulations decreased with increasing PVA concentration. The mass median aerodynamic diameter of the particles was within the respirable range. Entrapment efficiency increased with increasing PVA concentration; PLGA 85:15 showed better entrapment due to hydrophobic interactions with the drug. Compared to intravenously administered PGE1, microspheres prepared with PLGA 85:15 produced a 160-fold increase in the half-life of PGE1 following pulmonary administration. Although plain PGE1 showed rapid degradation in rat lung homogenate, PGE1 entrapped in the particles remained intact for about 8,h. Optimized formulations were demonstrated to be safe, based on analysis of cytotoxicity and lung-injury markers in BAL fluid. Overall, the data suggest that microspheric PGE1 formulations have the potential to be used as a noninvasive and controlled-release alternative to the current medications used for treatment of pulmonary arterial hypertension that are administered by continuous infusion or require multiple inhalations. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99: 1774,1789, 2010 [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] Lung-specific delivery of paclitaxel by chitosan-modified PLGA nanoparticles via transient formation of microaggregatesJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 3 2009Rui Yang Abstract Chitosan-modified paclitaxel-loaded poly lactic- co -glycolic acid (PLGA) nanoparticles with a mean diameter of 200,300 nm in distilled water were prepared by a solvent evaporation method. The mean diameter increased dramatically in contact with the mouse (CDF1) plasma, as a function of chitosan concentration in the modification solution (e.g., 2670.5 nm for 0.7% chitosan-modified nanoparticles, NP3), but reverted to almost its original size (i.e., 350.7 nm for NP3) following 5 min of gentle agitation. The zeta potential of PLGA nanoparticles was changed to positive by the chitosan modification. The in vitro uptake into, and cytotoxicity of the nanoparticles against, a lung cancer cell line (A549) were significantly increased by the modification. Most importantly, a lung-specific increase in the distribution index of paclitaxel (i.e., AUClung/AUCplasma) was observed for chitosan-modified nanoparticles (e.g., 99.9 for NP3 vs. 5.4 for TaxolÔ) when nanoparticles were administered to lung-metastasized mice via the tail vein at a paclitaxel dose of 10 mg/kg. Transient formation of aggregates in the blood stream followed by enhanced trapping in the lung capillaries, and electrical interaction-mediated enhanced uptake across the endothelial cells of the lung tumor capillary appear to be responsible for the lung-tumor-specific distribution of the chitosan modified nanoparticles. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:970,984, 2009 [source] Methotrexate loaded poly(l -lactic acid) microspheres for intra-articular delivery of methotrexate to the jointJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 4 2004Linda S. Liang Abstract A controlled release delivery system that localizes methotrexate (MTX) in the synovial joint is needed to treat inflammation in rheumatoid arthritis (RA). The purpose of this work was to develop and characterize MTX loaded poly(l -lactic acid) (PLLA) microspheres and evaluate in vivo tolerability and MTX plasma concentrations following intra-articular injection into healthy rabbits. MTX loaded PLLA (2 kg/mole) microspheres were prepared using the solvent evaporation method and characterized in terms of size, molecular weight, thermal properties, and release rates into phosphate buffered saline (PBS) (pH 7.4) at 37°C. Biocompatibility was evaluated by observing the swelling of the joints of the rabbits and histological analysis following the injection of the microspheres. MTX concentrations in the plasma and urine samples of rabbits were evaluated by high-performance liquid chromatography (HPLC). MTX loaded microspheres showed a rapid burst phase followed by a slow release phase. MTX loaded and control microspheres were biocompatible and plasma concentrations of MTX were tenfold higher in rabbits injected intra-articularly with free MTX than MTX microspheres. MTX microspheres may retain the drug in the joint by reducing clearance from the joint into the blood. © 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 93: 943,956, 2004 [source] Improvement of dissolution and oral absorption of ER-34122, a poorly water-soluble dual 5-lipoxygenase/cyclooxygenase inhibitor with anti-inflammatory activity by preparing solid dispersionJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 1 2002Ikuo Kushida Abstract Several formulation approaches were attempted to improve the dissolution and the oral absorption of ER-34122, which is a novel dual 5-lipoxygenase/cyclooxygenase inhibitor with potent anti-inflammatory activity. The solid dispersion of ER-34122 with hydroxypropylmethylcellulose (TC-5RW), which is an inert solid carrier, resulted in a significant improvement in the dissolution rate of ER-34122. The solid dispersion was prepared by a solvent evaporation method using ethanol and water. The solid-state characteristics of the solid dispersion, the corresponding physical mixture, and ER-34122 alone were investigated by X-ray powder diffraction, Fourier transform infrared spectroscopy (FTIR), and an automated controlled-atmosphere microbalance. The X-ray powder diffraction patterns suggest that the solid dispersion exists in a totally amorphous state and the others exist in a crystalline state. The FTIR spectra results suggest that ER-34122 can interact with TC-5RW through intermolecular hydrogen bonding in the solid dispersion. This interaction may cause a stabilization of ER-34122 in the higher-energy, faster-dissolving amorphous state. The dissolution rate of ER-34122 from the solid dispersion was significantly greater than that from the physical mixture or the pure drug. Furthermore, when orally administrated to beagle dogs, ER-34122 showed about a 100-fold increase in both maximum concentration (Cmax) and area under the curve of concentration versus time (AUC) compared with the pure drug. Consequently, it was determined that the solid dispersion technique with TC-5RW provides a promising way to increase the dissolution rate and the oral absorption of poorly water-soluble drugs such as ER-34122. © 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:258,266, 2002 [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] Temperature dependence of electrical resistivity in carbon nanofiber/unsaturated polyester nanocompositesPOLYMER ENGINEERING & SCIENCE, Issue 7 2008Toshiaki Natsuki This article described the temperature dependence of electrical resistivity for carbon nanofiber (CNF)/unsaturated polyester resin (UPR) nanocomposites prepared by a solvent evaporation method. It was found that the CNF/UPR nanocomposites had quite low electrical percolation threshold due to CNFs having a large aspect ratio and being well dispersed into the UPR matrix. A sharp decrease in the electrical resistivity was observed at about 1 wt% CNF content. The influence of CNF content on the electrical resistivity was investigated as a function of temperature in detail. The nanocomposites showed a positive temperature coefficient effect for the resistivity, and had a strong temperature dependence near the percolation threshold. When the number of thermal cycles was increased, the electrical resistivity decreased and had a weak temperature dependence, especially in the case of melting temperature. Moreover, the size influences of CNFs on the electrical properties of nanocomposites were analyzed and discussed. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers [source] 2261: Development and evaluation of PLGA nanoparticles with cyclosporine and the inclusion of HP,CD for ocular useACTA OPHTHALMOLOGICA, Issue 2010K HERMANS Ocular delivery of peptides requires new concepts in order to optimize the bioavailability and its therapeutic effect. The first peptide selected in present research project is Cyclosporine A (CyA) used in the treatment of the dry eye syndrome and against corneal graft rejection. The aim of the project is the development of nanoparticles with physicochemical properties for a suitable and prolonged release of CyA, using a factorial design. These drug delivery systems will be produced employing PLGA using the emulsification solvent evaporation method. Positively charged polymers as chitosan or Eudragit® will be incorporated to obtain nanoparticles with a positive particle charge. Electrostatic interactions with the negatively charged mucins lead to a prolonged residence time at the precorneal area. Nanoparticles will be evaluated on zeta potential, particle size and their in vitro drug release properties. CyA and CyA complexed with HP,CD will be compared. The most suitable preparations will be selected in a next phase of the project for an in vivo study using an animal model. [source] | |||||||||||||