对乙酰氨基酚复合微囊缓释栓的制备及体外释放度研究

目的:采用复凝聚法制备对乙酰氨基酚(AAP)微囊并考察其体外释药行为。制备AAP复合微囊栓剂,具有良好释放效果。方法:考察复凝聚法制备AAP微囊过程的处方和工艺因素,并进行正交试验设计,筛选出最佳条件制备AAP微囊并考察其体外释药行为。同时采用复合缓释技术(速释部分+微囊缓释)制备复合微囊缓释栓剂,考察其释药行为。结果:建立了复凝聚法制备AAP微囊方法,优化后的制备条件为:明胶阿拉伯胶囊材用量各为7 g(溶液浓度7%),药物用量为8 g,搅拌速度为300 r·min^-1,制备温度55℃。此条件制备的微囊形态圆整,粒径均匀,重复性好,包封率为(79.71±0.10)%,载药量为23.11±0.69%。微囊有缓释效果,拟合缓释方程符合一级方程。制备的复合微囊栓与普通栓剂相比,具有更好的释放效果,其中缓释过程药物释放符合Higuchi方程。结论:基于普通栓剂与复合微囊技术制备的新型AAP栓具有更佳的释药特性。     

雌二醇生物可降解缓释微球的制备四氢呋喃的加入对微球性质的影响

目的　在本实验中 ,以生物可降解和生物相容性良好的聚乳酸 (PLA)或乳酸 -乙醇酸共聚物 (PLGA)为载体材料制备含有雌二醇药物的缓释微球 ,考察在制备过程中水溶性更强的四氢呋喃的加入对微球性质的影响。方法　以乙酸乙酯和四氢呋喃为有机溶剂、采用乳化 -溶剂萃取法制备含药微球 ,分别从成球性、粒径、包封率和体外释药等方面 ,进行制备工艺研究以及微球相关性质的研究。结果　在乙酸乙酯中加入四氢呋喃 ,使包封率降低 ,但在乙酸乙酯体积比大于 5 0 %时 ,增加四氢呋喃的用量对包封率无明显影响。相同条件下 ,在考察范围内 ,粒径随四氢呋喃用量比例的增大而增大 ,而载体的性质和微球含药量是影响微球释药的主要因素。结论　尽管在制备过程中的油相中加入了水溶性更强的四氢呋喃 ,但是通过控制制备工艺和条件 ,仍然可以得到球形态好、有适当粒径分布范围、载药量高并且突释程度小的雌二醇生物可降解缓释微球     

盐酸克林霉素微囊的体外释药及其影响因素的考察

目的 采用液中干燥法制备盐酸克林霉素微囊，并考察其体外释药特性。方法 以乙基纤维素为囊材制备微囊．用浆法研究其体外释药的影响因素。结果 药物释放速率随微囊粒径减小而增加；囊材粘度增加，药物释放速率降低；附加剂滑石粉对药物释放的影响较复杂，随着滑石粉比例增加．药物释放速率增加．但至一定比例后．速率降低。与市售胶囊相比．有明显缓释作用。结论 液中干燥法制备的盐酸克林霉素微囊有显著的缓释作用．有良好的开发应用前景。     

关节腔注射用氟比洛芬PLGA缓释微球的制备及体外释放特性研究

目的制备关节腔注射用氟比洛芬(FP)缓释微球并研究其体外释药特性。方法以聚乳酸-羟基乙酸共聚物(PLGA)为材料,采用乳化-溶剂挥发法制备微球;正交设计法优化微球的制备工艺;采用透析法研究体外释药特性,UV法测定FP的含量。结果正交试验表明,PLGA的浓度是影响微球包封率的非常显著性因素。微球粒径范围为1.5~24.3μm,平均粒径为10.6μm,载药量为7.1%(W/W),包封率为92.7%,体外释药符合Higuchi方程,释放时间显著延长。结论本法制备的FP微球粒径大小适宜,具有明显的缓释作用,符合关节腔注射给药设计要求。     

甲睾酮聚乳酸缓释微球的制备

目的：制备甲睾酮聚乳酸缓释微球。方法：用乳化溶剂挥发法制备甲睾酮聚乳酸缓释微球。先设计单因素试验筛选制备微球的处方中的聚乳酸分子量、聚乳酸浓度、投药比（甲睾酮：聚乳酸）;再采用正交试验优化制备微球的温度、转速、聚乳酸浓度、投药比。考察微球表面形态、粒径、载药量、包封率、168h体外累积释药率,并对微球的体外释药模型进行零级、一级、Higuchi、双相动力学方程拟合。结果：优选结果为聚乳酸分子量11万、温度30℃、转速500r·min-1、聚乳酸浓度0.1g·mL-1、投药比1：5。采用最佳工艺条件制备的微球形态圆整,平均粒径为（2.5±0.2）μm,载药量为6.18%～6.62%,包封率为89.9%～91.3%,168h体外累积释药率为（41.8±0.1）%,微球的体外释药符合双相动力学方程（r=0.9945）。结论：甲睾酮聚乳酸缓释微球制备工艺稳定,具有良好的缓释能力。     

喷雾干燥法制备丹酚酸壳聚糖微囊

目的以壳聚糖为载体制备丹酚酸微囊,并对其体外释药模式进行研究。方法以收率和载药量为指标,考察处方及工艺因素对微囊的影响,并对处方和工艺进行优化。结果壳聚糖质量浓度1.5%,丹酚酸与壳聚糖的质量比1∶3,进风温度190℃,蠕动泵速度300mL.h-1,所制得的微囊表面圆整,载药量为25.99%,收率为51.88%,包封率为86.21%,平均粒径为105.6nm。体外具有一定的缓释特性,在0～240min内拟合一级释药模型方程ln(1-Q)=-0.236 9 t+4.591 7,r=0.920 3。结论采用喷雾干燥法制得的丹酚酸微囊,收率和载药量较高,制备工艺简单,可望成为实现中药微球工业化的有效方法。     

酮咯酸氨丁三醇微囊的研究

目的制备酮咯酸氨丁三醇的海藻酸钠-壳聚糖微囊，对其体外释药特性进行考察。方法采用滴液法制备微囊，以均匀设计优化制备工艺，溶出度测定法考察微囊体外释药特性。结果80％微囊粒径在200-250μm，微囊表面光滑圆整无粘连，包封率达90．56％，载药量达43．65％；微囊在人工胃液和蒸馏水中的释药规律符合Higuchi方程。结论酮咯酸氨丁三醇的海藻酸钠-壳聚糖微囊在人工胃液和蒸馏水中具有缓释作用。     

米托蒽醌聚乳酸缓释毫微粒针剂的制备

在单因素实验的基础上用均匀设计优化了米托蒽醌聚乳酸缓释微粒的制备方法。空白和载药微粒的平均粒径分别为１２９．９６和１３３．１５ｎｍ;包封率为９９．２３％;载药量为１３．５６％;制备收率为９９．３％。以乳和支架剂制得的冻干针剂外型美观、理化性质稳定,再分散后平均粒径为１５２．０２ｎｍ。用动态透析系统考察了不同分子量聚乳酸毫微粒冻干针剂的体外释药特性,结果显示高分子量聚乳酸微粒的释药速度明显慢于低分子     

雌二醇阴道用缓释胶囊的制备及体外释放行为的考察

目的制备雌二醇阴道用缓释胶囊,并考察其体外释药行为。方法以聚维酮K30为载体,溶剂法制备雌二醇固体分散微粒;采用溶出度测定仪和动态透析2种方法分别评价优化后的处方及对照片剂的体外药物释放情况。结果优化的处方与雌二醇阴道片释放行为较为接近,具有良好的持续性低剂量释药的作用。结论雌二醇阴道用缓释胶囊是一种理想的阴道给药新剂型。     

难溶性药物布洛芬药物树脂复合物的制备及其体外释放研究

目的:制备布洛芬药物树脂复合物,并考察其体外释药动力学。方法:将布洛芬制备成可溶性的钠盐,采用不同交联度的离子交换树脂为载体以静态法制备布洛芬树脂复合物,并对布洛芬树脂复合物释放的影响因素进行考察。结果:随着树脂交联度的减小,树脂对布洛芬的载药速率变快,载药量增加。体外释药动力学研究表明,布洛芬药物树脂的释药速率随着释放介质离子强度的增加,温度的升高,以及树脂交联度和粒径的减小而加快;且布洛芬药物树脂的释放为pH依赖型。结论:采用离子交换树脂为载体制备的布洛芬树脂复合物具有一定的缓释特征。     

Preparation and evaluation of poly (D,L-lactic acid) (PLA) or D,L-lactide/glycolide copolymer (PLGA) microspheres with estradiol

PLA/PLGA was used for biodegradable and biocompatible carriers to achieve sustained release of estradiol. Microspheres were formed by an emulsification-solvent evaporation method, and then their properties and in vitro drug release behavior were examined including amongst others the effects of the concentration of PVA in the aqueous phase, the concentration of PLA in the organic phase, the stirring speed, the volume ratio of O/W, the weight ratio of E2/PLA fed, and the type and molecular weight of the polymers.     

Characterization of Poly(glycolide-co-D,L-lactide)/Poly(D,L-lactide) Microspheres for Controlled Release of GM-CSF

Purpose. This study describes the preparation and characterization of a controlled release formulation of granulocyte-macrophage colony-stimulating factor (GM-CSF) encapsulated in poly(glycolide-co-D,L-lactide) (PLGA) and poly(D,L-lactide) (PLA) microspheres. Methods. GM-CSF was encapsulated in PLGA/PLA microspheres by a novel silicone oil based phase separation process. Several different blends of PLGA and low molecular weight PLA were used to prepare the microspheres. The microspheres and the encapsulated GM-CSF were extensively characterized both in vitroand in vivo. Results. Steady release of GM-CSF was achieved over a period of about one week without significant 'burst' of protein from the microspheres. Analysis of microsphere degradation kinetics by gel permeation chromatography (GPC) indicated that low molecular weight PLA enhanced the degradation of the PLGA and thereby affected release kinetics. GM-CSF released from the microspheres was found to be biologically active and physically intact by bioassay and chromato-graphic analysis. Analysis of serum from mice receiving huGM-CSF indicated that the GM-CSF was biologically active and that a concentration of greater than 10 ng/mL was maintained for a period lasting at least nine days. MuGM-CSF was not detected followingin vivo administration of muGM-CSF microspheres. The tissues of mice receiving muGM-CSF microspheres were characterized by infiltration of neutrophils, and macrophages which were in significant excess of those found in mice administered with placebo controls (i.e. microspheres without GM-CSF). Conclusions. This study demonstrates the influence of formulation parameters on the encapsulation of GM-CSF in PLGA/PLA microspheres and its controlled release in biologically active form. The intense local tissue reaction in mice to muGM-CSF microspheres demonstrates the importance of the mode of delivery on the pharmacologic activity of GM-CSF.     

Preparation, characterization, cytotoxicity and transfection efficiency of poly(DL-lactide-co-glycolide) and poly(DL-lactic acid) cationic nanoparticles for controlled delivery of plasmid DNA

The objective of this study was to investigate the effect of formulation parameters (i.e. polymer molecular weight and homogenization speed) on various physicochemical and biological properties of cationic nanoparticles. Cationic nanoparticles were prepared using different molecular weights of poly(DL-lactide-co-glycolide) (PLGA) and poly(DL-lactic acid) (PLA) by double emulsion solvent evaporation at two different homogenization speeds, and were characterized in terms of size, surface charge, morphology, loading efficiency, plasmid release, plasmid integrity, cytotoxicity, and transfection efficiency. Cationic surfactant, cetyltrimethylammonium bromide (CTAB), was used to provide positive charge on the surface of nanoparticles. Reporter plasmid gWIZ Beta-gal was loaded on the surface of nanoparticles by incubation. Use of higher homogenization speed and lower molecular weight polymer led to a decrease in mean particle size, increase in zeta potential, increase in plasmid loading efficiency, and a decrease in burst release. The nanoparticles displayed good morphology as evident from scanning electron micrographs. In vitro cytotoxicity study by MTT assay showed a low toxicity. Structural integrity of the pDNA released from nanoparticles was maintained. Transfecting human embryonic kidney (HEK293) cells with nanoparticles prepared from low molecular weight PLGA and PLA resulted in an increased expression of beta-galactosidase as compared to those prepared from high molecular weight polymer. Our results demonstrate that the PLGA and PLA cationic nanoparticles can be used to achieve prolonged release of pDNA, and the plasmid release rate and transfection efficiency are dependent on the formulation variables.     

Physicomechanical properties of biodegradable poly(D,L-lactide) and poly(D,L-lactide-co-glycolide) films in the dry and wet states

The objective of this study was to investigate the mechanical properties (% elongation and puncture strength) of poly(D,L-lactide) (PLA) and poly(D,L-lactide-co-glycolide) (PLGA) films as a function of exposure time to an aqueous medium and to correlate the mechanical properties to the degradation/erosion of the polymer as a function of the type of polymer [PLA, weight-average molecular weight (M(W)) 270,300, or PLGA 50:50, M(W) 56,500], the type of plasticizer [(triethyl citrate (TEC) or acetyltributyl citrate (ATBC)], and the exposure time to pH 7.4 phosphate buffer. The glass transition temperature of the films was measured by differential scanning calorimetry (DSC), the molecular weight by size exclusion chromatography (SEC), and the polymer erosion and hydration gravimetrically. The mechanical properties were strongly affected by the type of polymer and plasticizer. PLGA films showed a faster loss of mechanical integrity. TEC, the water-soluble plasticizer, leached from the films, resulting in major differences in the mechanical properties (flexibility) when compared with films plasticized with the more permanent, water-insoluble ATBC. A significant difference in M(W) decrease was seen between plasticizer-free and plasticizer-containing PLA films, but not for PLGA films. Plasticized PLA films, which were above their glass transition temperature in the rubbery state, showed a faster decrease in M(W) than plasticizer-free PLA ones, which were in the glassy state. The plasticizer addition to the lower M(W) PLGA did not enhance the polymer degradation; the plasticizer-free PLGA was already in the rubbery state. Major differences between the two polymers were also seen in the mass loss and the water uptake studies. After 4 weeks, the mass loss was between 2.6 and 7.0% and the water uptake between 10.1 and 21.1% for PLA films, whereas for PLGA films, the mass loss was between 40.3 and 51.3% and the water uptake between 221.9 and 350.6%. 2000 Wiley-Liss, Inc.     

Ketotifen-loaded microspheres prepared by spray-drying poly(D,L-lactide) and poly(D,L-lactide-co-glycolide) polymers: characterization and in vivo evaluation

Ketotifen (KT) was encapsulated into poly(D,L-lactide) (PLA) and poly(D,L-lactide-co-glycolide) (PLGA 50/50) by spray-drying to investigate the use of biodegradable drug-loaded microspheres as delivery systems in the intraperitoneal cavity. Ketotifen stability was evaluated by HPLC, and degradation was not observed. Drug entrapment efficiency was 74 +/- 7% (82 +/- 8 microg KT/mg for PLA) and 81 +/- 6% (90 +/- 7 microg KT/mg for PLGA 50/50). PLA microspheres released ketotifen (57% of encapsulated KT) in 350 h at two release rates (221 microg/h, 15 min to 2 h; 1.13 microg/h, 5-350 h). A quicker release of ketotifen took place from PLGA 50/50 microspheres (67.4% of encapsulated KT) in 50 h (322 microg/h, 15 min to 2 h; 16.18 microg/h, 5-50 h). After intraperitoneal administration (10 mg KT/kg b.w.), microsphere aggregations were detected in adipose tissue. Ketotifen concentration was determined in plasma by HPLC. The drug released from PLA and PLGA 50/50 microspheres was detected at 384 and 336 h, respectively. Noncompartmental analysis was performed to determine pharmacokinetic parameters. The inclusion of ketotifen in PLGA and PLA microspheres resulted in significant changes in the plasma disposition of the drug. Overall, these ketotifen-loaded microspheres yielded an intraperitoneal drug release that may be suitable for use as delivery systems in the treatment of inflammatory response in portal hypertension.     

Self-Assembled Biodegradable Nanoparticles Developed by Direct Dialysis for the Delivery of Paclitaxel

Purpose The main objective of this study was to obtain self-assembled biodegradable nanoparticles by a direct dialysis method for the delivery of anticancer drug. The in vitro cellular particle uptake and cytotoxicity to C6 glioma cell line were investigated. Methods Self-assembled anticancer drugs—paclitaxel-loaded poly(d,l-lactic-co-glycolic acid) (PLGA) and poly(l-lactic acid) (PLA) nanoparticles—were achieved by direct dialysis. The physical and chemical properties of nanoparticles were characterized by various state-of-the-art techniques. The encapsulation efficiency and in vitro release profile were measured by high-performance liquid chromatography. Particle cellular uptake was studied using confocal microscopy, microplate reader, and flow cytometry. In addition, the cytotoxicity of this drug delivery system was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on C6 glioma cell line to predict the possible dose response of paclitaxel-loaded PLGA and PLA nanoparticles. Results PLGA and PLA nanoparticles with or without vitamin E tocopherol polyethylene glycol succinate (TPGS) as an additive were obtained, in which the sustained release of paclitaxel of more than 20 days was achieved. The coumarin6-loaded PLGA and PLA nanoparticles could penetrate the C6 glioma cell membrane and be internalized. The cytotoxicity of paclitaxel-loaded nanoparticles seemed to be higher than that of commercial Taxol? after 3 days incubation when paclitaxel concentrations were 10 and 20 μg/ml. Conclusions Direct dialysis could be employed to achieve paclitaxel-loaded PLGA and PLA nanoparticles, which could be internalized by C6 glioma cells and enhance the cytotoxicity of paclitaxel because of its penetration to the cytoplasm and sustained release property.     

Vancomycin release from poly(D,L-lactide) and poly(lactide-co-glycolide) disks

A biodegradable and biocompatible polymeric system was developed for the controlled release of vancomycin for the treatment of brain abscesses. Poly(D,L-lactic acid) (PLA) and its copolymers poly(lactide-co-glycolide) PLGA 90:10 and PLGA 70:30, were prepared. Polymer disks containing vancomycin (VN) were prepared by solvent casting from methylene chloride solutions. Degradation of the polymer disk was studied by scanning electron microscopy, NMR and GPC. SEM revealed an increasing degree of degradation with time with both PLGAs, the effect being more distinct in the PLGA with the higher glycolide content (PLGA 70:30), which was confirmed with GPC, which showed both a decrease in the molecular weights of PLGA and a decrease in the heterogeneity index (chain length distribution) upon incubation in isotonic phosphate buffer at 37#176;C for up to 5 weeks. NMR showed a decrease in the CH 2 contents of the copolymers, implying that the glycolide component of the copolymers is being preferentially degraded. In situ, vancomycin release behaviour of the disks in pH 7.4 phosphate buffer saline (PBS) was followed for ~2 months in a static system. It was observed that release was according to Higuchi kinetics (Q vs. t 1/2) , and introduction of low molecular weight PLA or hydrophilic compounds like PEG increased the release rate.     

5-Fluorouracil plasma levels and biodegradation of subcutaneously injected drug-loaded microspheres prepared by spray-drying poly(D,L-lactide) and poly(D,L-lactide-co-glycolide) polymers

Microspheres (MS) of 5-fluorouracil-loaded poly(D,L-lactide) (PLA), poly(D,L-lactide-co-glycolide) 75/25 (PLGA 75/25) and poly(D,L-lactide-co-glycolide) 50/50 (PLGA 50/50) prepared by the spray-drying technique were subcutaneously injected in the back of Wistar rats in order to evaluate the 5-fluorouracil (5-FU) release and the biodegradation characteristics. Determination of plasma 5-FU concentration by HPLC with analysis of data using a non-compartmental model showed drug in plasma between 9 and 14 days after administration of drug-loaded PLGA 50/50 or PLA and PLGA 75/25 microspheres, respectively, with a maximum drug concentration of 2.4+/-0.2microg/mL at 24h (5-FU-loaded PLGA 50/50 MS), 2.5+/-0.1microg/mL at 48h (5-FU-loaded PLGA 75/25 MS), and 2.3+/-0.1microg/mL at 24h (5-FU-loaded PLA MS). Pharmacokinetically, a significant increase of AUC (up to 50 times) and MRT (up to 196 times) of 5-FU with regard to the administration of the drug in solution was observed. Scanning electron microscopy and histological studies indicated that a small fibrous capsule was observed around the microspheres in the site of injection. One month after the injection of PLGA 50/50 MS and 2 months after the injection of PLGA 75/25 and PLA MS, masses of polymers, instead of single microspheres, were observed. Close to them, macrophagic cells were present, and blood vessels were observed in the connective tissue. Total absence of fibrous capsule and injected microspheres was observed after 2 (for PLGA 50/50 MS) or 3 (PLGA 75/25 and PLA MS) months.     

Vancomycin release from poly(D,L-lactide) and poly(lactide-co-glycolide) disks.

A biodegradable and biocompatible polymeric system was developed for the controlled release of vancomycin for the treatment of brain abscesses. Poly(D,L-lactic acid) (PLA) and its copolymers poly(lactide-co-glycolide) PLGA 90:10 and PLGA 70:30, were prepared. Polymer disks containing vancomycin (VN) were prepared by solvent casting from methylene chloride solutions. Degradation of the polymer disk was studied by scanning electron microscopy, NMR and GPC. SEM revealed an increasing degree of degradation with time with both PLGAs, the effect being more distinct in the PLGA with the higher glycolide content (PLGA 70:30), which was confirmed with GPC, which showed both a decrease in the molecular weights of PLGA and a decrease in the heterogeneity index (chain length distribution) upon incubation in isotonic phosphate buffer at 37 degrees C for up to 5 weeks. NMR showed a decrease in the CH2 contents of the copolymers, implying that the glycolide component of the copolymers is being preferentially degraded. In situ, vancomycin release behaviour of the disks in pH 7.4 phosphate buffer saline (PBS) was followed for approximately 2 months in a static system. It was observed that release was according to Higuchi kinetics (Q vs. t(1/2)), and introduction of low molecular weight PLA or hydrophilic compounds like PEG increased the release rate.     

盐酸表柔比星-聚乳酸-羟基乙酸共聚物纳米粒的制备

摘要目的制备盐酸表柔比星 聚乳酸 羟基乙酸（PLGA）共聚物纳米粒,对其进行质量评价。方法采用乳化 溶剂挥发法制备盐酸表柔比星纳米粒;对主要处方因素如PLGA用量、外水相中聚山梨酯 80用量、泊洛沙姆188和聚山梨酯 80比例进行正交设计,以药物的包封率、载药量和药物利用率等为考察指标。结果采用优化后处方制得的纳米粒药物包封率为（32.6±1.2）%,载药量为（7.2±0.5）%,药物利用率为（51.6±3.4）%,纳米粒平均粒径166.6 nm,药物可持续160 h释放。结论该方法制备盐酸表柔比星纳米粒工艺简单,无需使用聚乙烯醇,药物释放缓慢。