米托蒽醌聚乳酸缓释毫微粒冻干针剂的体外释药物特性研究

选择含１％维生素Ｃ的生理盐水作释药介质，用动态透析系统和分光光度法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。分离子量聚乳酸毫微粒的释药速度明显慢于低分子量的聚乳酸毫微粒。通过选择适应分子量的聚乳酸制备毫微粒可控制其释药速度。     

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     

聚乳酸分子量对利福平聚乳酸微球性质的影响

目的 :考察聚乳酸分子量对利福平聚乳酸微球性质的影响。方法 :采用分散一溶媒扩散法制备利福平聚乳酸微球 ,测定微球的粒径分布和包封率 ,进行体外释药和稳定性试验。结果 :在本制备方法中 ,聚乳酸分子量对微球粒径分布的影响作用不明显 ;药物包封率随聚乳酸分子量增大而增加 ;聚乳酸分子量减小 ,微球体外释药速度加快。稳定性试验表明 ,微球在 4℃和室温 (2 0～ 2 5℃ )条件下性质稳定 :3 7℃条件下因聚乳酸软化 ,微球发生粘连聚集。结论 :应根据实验目的选择适宜分子量的聚乳酸 ,以获得所需性质的微球。     

聚乳酸及其共聚物在药物释放系统中的研究进展

生物可降解的聚乳酸及其共聚物被广泛用作药物载体 ,以控制释药速度 ,这是目前研究和应用的热点。本文综述聚乳酸及其共聚物在微粒给药系统、植入剂、膜剂等中的研究进展。     

聚乳酸及其共聚物在药物释放系统中的研究进展

生物可降解的聚乳酸及其共聚物被广泛用作药物载体,以控制释药速度,这是目前研究和应用的热点。本文综述聚乳酸及其共聚物在微粒给药系统、植入剂、膜剂等中的研究进展。     

阿克拉霉素A聚乳酸毫微粒冻干针剂在兔体内的血浆药动学研究

目的 :研究阿克拉霉素A聚乳酸毫微粒冻干针剂在兔体内的血浆药代动力学。方法 :采用HPLC法测定给药后的血浆药物浓度。结果 :经3p87药动学程序处理 ,得到两种制剂的药代动力学参数。结论 :与阿克拉霉素A相比 ,阿克拉霉素A聚乳酸毫微粒具有显著的缓释特性     

阿柔比星A聚乳酸毫微粒冻干针剂小鼠体内分布研究

对阿柔比星Ａ冻干针剂与阿柔比星Ａ聚乳酸毫微粒冻干针剂给予小鼠尾静脉注射后体内分布比较，采用ＨＯＬＣ法分别测定小鼠给药后血液及主要脏器中ＡＣＲＢ０Ａ浓度。结果阿柔比星Ａ聚乳酸毫微粒在小鼠肝脏中的浓度高于对照品浓度。     

阿柔比星A聚乳酸毫微粒主要性质研究

目的：对载药毫微粒主要质量指标载药量、包封率及其关系,粒径及其分布进行研究,方法：以阿柔比星Ａ聚乳酸微粒为研究对象,以分光光度测定载药量与包封率,以激光粒度分析仪测定粒径及其分布。结果：阿柔比星Ａ聚乳酸毫微粒平均载药量为１８．５％。平均包封率为８６．７％,平均数目径为８０ｎｍ,平均体积径为２３０ｎｍ。结论：载药量与包封率之间具有一定关系。体积径分布是载药毫微粒粒径分布评价不可忽视的内容。     

生物降解性微粒和毫微粒在药物控释方面的新进展

药学、化工和其它学科的研究者努力设计生物降解聚合物使其降解机理和机械性能符合要求。生物降解聚合物的优点在于完全释药后不需外科手术将其取出，另外可将药物直接输送到体循环。根据实用需要，药物和聚合物的组合方式有多种。其中微粒制剂的应用最广，种类最多：口服、肌注、皮下注射及靶向约药。本文着重介绍生物降解性聚乳酸、聚乙醇酸或其共聚物得的微粒、毫微粒在药物控释中的最新研究进展。     

毫微粒载体研究进展

毫微粒作为药物载体具有许多优点，现已成为药剂学界研究的前沿热点之一。本文以三种常见的可生物降解聚合材料为例，综述了毫微粒的制备方法，同时介绍了毫微粒载体在靶向释药，性能改善方面的最新研究成果。     

Evaluation of biodegradable poly(lactide) pellets prepared by direct compression

Biodegradable pellets intended for either parenteral or oral use were successfully prepared from low molecular weight poly(DL-lactide) (low MW PLA, MW' = 2000) or a relatively high molecular weight poly(L-lactide) (L-PLA, MW = 215,000) sample by a simple direct compression technique without the use of heat or organic solvents. The energy imparted during the compression step caused fusion of the low MW PLA particles. Pellets prepared from low MW PLA swelled considerably before eroding in pH 7.4 buffer, but acted as an enteric matrix in 0.1 M HCl. This was attributed to the high carboxyl endgroup:polymer chain ratio which increased with a decrease in molecular weight. Interactions between salts of basic drugs (quinidine sulfate or propranolol hydrochloride) and the polymeric carboxyl endgroups caused retardation in the drug release from low MW PLA pellets. The drug release from L-PLA pellets was independent of the pH of the dissolution media and drug-polymer interactions were absent. The drug release could be increased by admixing sodium chloride prior to compression, or reduced by dipping the pellets into methylene chloride for a short period of time.     

雌二醇聚乳酸类微囊的制备与体外评价

目的　以聚乳酸或乳酸 乙醇酸共聚物为载体材料制备雌二醇缓释微囊。方法　实验中采用乳化 溶剂萃取法制备微囊 ,考察了影响微囊特性以及体外释药的各种因素 ,采用单因素试验方差分析进行因素影响的显著性检验 ,并在此基础上采用T方法进行两两间多重比较 ,进一步考察因素各水平间差异的显著性。结果　结果表明 ,粒径和加水萃取速度对雌二醇微囊的包封率有显著性影响 (P <0 0 1) ;随油相载体的浓度以及加水萃取速度对微囊的粒径影响显著 (P <0 0 1)。体外释药研究表明 ,加水萃取速度和载体的型号和分子量对微囊释药影响显著 (P <0 0 1)。但这些影响因素的各水平之间的差异性并不都具有显著性。结论　通过改变处方以及制备工艺可以得到具有不同性质的雌二醇聚乳酸类缓释微囊     

Production of insulin-loaded poly(ethylene glycol)/poly(l-lactide) (PEG/PLA) nanoparticles by gas antisolvent techniques.

Insulin and insulin/poly(ethylene glycol) (PEG)-loaded poly(l-lactide) (PLA) nanoparticles were produced by gas antisolvent (GAS) CO(2) precipitation starting from homogeneous polymer/protein organic solvent solutions. Different amounts of PEG 6000 (0, 10, 30, 50, 100, and 200% PEG/PLA w/w) or concentration of 30% PEG/PLA with PEGs with different molecular weight (MW; 350, 750, 1900, 6000, 10,000, and 20,000) were used in the preparations. The process resulted in high product yield, extensive organic solvent elimination, and maintenance of > 80% of the insulin hypoglycemic activity. Nanospheres with smooth surface and compact internal structure were observed by scanning electron microscopy. The nanospheres presented a mean particle diameter in the range 400-600 nm and narrow distribution profiles. More than 90% of drug and PEG were trapped in the PLA nanoparticles when low MW PEGs were used in the formulation, whereas the addition of high MW PEGs significantly reduced the loading yield. In all cases, in vitro release studies showed that only a little amount of drug was released from the preparations. However, formulations containing low MW PEGs allowed for a slow but constant drug release throughout 1500 h, whereas a burst was obtained by increasing the PEG MW. In conclusion, the GAS process offers a mean to produce protein-loaded nanoparticles possessing the prerequisites for pharmaceutical applications. The PEG added to the formulation was found to play a key role in the simultaneous solute precipitation phenomena and in determining the release behavior and the chemical-physical properties of the formulation.     

Novel,dynamic on-line analytical separation system for dissolution of drugs from poly(lactic acid) nanoparticles

A novel method for investigating drug release in a dynamic manner from nanoparticles including, but not limited to, biodegradable poly(lactic acid) (PLA) is reported. The PLA nanoparticles were prepared by the nanoprecipitation method. Two poorly soluble drugs, beclomethasone dipropionate (BDP) and indomethacin, were encapsulated into PLA nanoparticles, and their dissolution from the nanoparticles were followed in a dynamic way. The on-line method comprised a short column (vessel) packed with the PLA nanoparticles, on-line connected to an analytical liquid chromatographic column via a multiport switching valve equipped with two loops. The system allowed monitoring of the drug release profiles in real time, and the conditions for the drug release could be precisely controlled and easily changed. The effects of solvent composition and temperature on the rate of dissolution of the drugs from the PLA nanoparticles were investigated. The system proved to be linear for the drugs tested over the concentration range 10–3000 ng (n = 6, R² = 0.999 and 0.997 for indomethacin and beclomethasone, respectively) and repeatable (RSD of peak areas <0.5%). The recoveries of the dissolution study were quantitative (120 and 103% for indomethacin and beclomethasone, respectively).     

In vitro delivery of a sparingly water soluble compound from PLA50 microparticles

The administration of a sparingly soluble drug is always problematic, especially when the drug has to be released from the degradable matrix of a polymeric drug delivery system. Attempts were made to achieve the complete release of 1-[2-(fluorobenzoyl) aminoethyl]-4-(7-methoxynaphtyl)piperazine (FAMP), a potential anxiolytic and antidepressor hydrophobic compound, from racemic poly(lactic acid) (PLA50)-based microparticles, 100% release was required at a low rate in order to allow monthly repeated S.C. or I.M. injections of this potent compound. FAMP-polymer combinations were made in the form of microspheres by the solvent evaporation technique. Release profiles were investigated under dynamic conditions by using a constant flow rate of pH 7.4 0.15 M phosphate buffer, used as a model of body fluids. Under these conditions, none of the microsphere compositions led to total release within a month, even when hydrophilic excipients, namely fructose and PEG were added. PLA50-FAMP microparticles with compositions and sizes similar to those of the microspheres, were then made by direct blending in dichloromethane, evaporation of the solvent, grinding and sieving. These formulations also failed in providing total drug release within 30 days, even at a high drug load. FAMP/PLA50/water-soluble additive, ternary grounded particles were finally prepared with fructose, PLA50 oligomers or poly(ethylene glycol) (PEG) as the additive. Only PLA50 grounded particles with percolating FAMP-PEG microdomains allowed 100% release of FAMP over a 30 day period, at a quasi constant rate which depended primarily on solubility and channelling provided the flow was slow enough. Data are discussed in terms of the accessibility of the entrapped drug to the aqueous medium.     

聚乳酸的降解性能及其微球剂的研究

目的 :研究聚乳酸的降解性能和制备聚乳酸红霉素微球。方法 :将聚乳酸薄膜置于模拟体液中水解 ,用正交设计优选微球制备工艺。结果 :分子量高的降解比分子量低的慢 ,消旋聚乳酸的降解比左旋聚乳酸的快。微球形态圆整 ,性质稳定 ,平均粒径为(10 98±0 15) μm ,体外释药符合Higuchi方程 (Q=28 067 +3 8515T1/2,r=0 9834)。结论 :聚乳酸的降解与分子量和构型有关 ,微球具有明显的缓释作用和满足肺靶向药物的要求     

In vivo evaluation of risperidone-SAIB in situ system as a sustained release delivery system in rats.

The objective of this study was to evaluate a sustained release sucrose acetate isobutyrate (SAIB) in situ system formulation of risperidone (RSP) in vivo. The formulation contained SAIB, ethanol, and polylactic acid (PLA) as a release regulator. In vivo pharmacokinetics (PK) studies have shown that PLA is effective in reducing the burst effect. After a 12.5mg/kg IM injection of a 25mg/g RSP-SAIB in situ system, the C(max) was markedly reduced from 944.1+/-80.2 to 330.4+/-33.6ng/ml by increasing PLA from 1% to 10% (w/w), the T(max) were prolonged from 2 to 4.3+/-2.0h, and the area under the curve from day 0 to 2 (AUC(0-2day)) was reduced significantly from 16294.8+/-3946.4 to 7025.3+/-1979.2ngh/ml. For the RSP-SAIB in situ system including 10% PLA, the high release rates over a short period allowed therapeutic plasma concentrations to be achieved in the initial stages after activation, and sustained release of the drug led to a stable plasma concentration (by day 25, the plasma concentration was 8% of the C(max)). These initial in vivo studies suggest that RSP-SAIB in situ system is effective as a sustained delivery system.     

布地奈德固体分散体增溶型渗透泵片的研制及其释药机制

制备布地奈德固体分散体增溶型单层渗透泵片（以下简称布地奈德渗透泵片）,并进行其释药机制研究。方法：用超临界流体技术制备的布地奈德-聚氧乙烯N750固体分散体作为含药片芯,以提高难溶性药物的溶解度;通过单因素实验优化片芯处方和包衣膜处方,制备布地奈德渗透泵片;设计实验考察包衣膜内外渗透压差对制剂稳态释药速率的影响,阐述其释药机制。结果：药物溶解度、促渗透剂种类和用量、增塑剂用量均对布地奈德渗透泵片的体外释药行为有影响,优化处方的体外释药方程为：Q=7.6077t＋0.7764,r=0.9997;其释药行为主要受包衣膜内外溶液渗透压控制,扩散释药仅占整个药物释放的30.39％。结论：渗透泵机制在布地奈德渗透泵片释药过程中占主导地位,体外释药符合零级动力学过程。     

Control release of prostaglandin E2 from polylactic acid microcapsules, microparticles and modified microparticles

Low molecular weight polylactic acid (PLA) microparticles containing prostaglandin E2 were prepared. An average particle size of 30 micron was obtained by grinding at low temperature. These particles were further treated by heating to modify the shape and the release pattern. Microscopic studies showed that the modified particles had a smoother surface than the non-modified particles. The drug was also incorporated into PLA microcapsules using the solvent evaporation process, but the incorporation efficiency was lower. We studied the release profiles of modified particles prepared using different molecular weight PLA. The release rate depended on the molecular weight with lower molecular weights having a greater release rate. In addition, the release studies showed different matrix forms made from the same molecular weight PLA had different release patterns. For example, the microcapsules released the drug very slowly whereas the modified particles exhibited a moderate release rate. It was also noted that the matrix release model could describe the release patterns of microcapsules and modified particles very well. However, the release patterns of non-modified microparticles did not follow this model.     

聚乳酸、聚乳酸乙醇酸共聚物微球的制备及体外释放影响因素研究进展

目的：对近年来以PLA，PLGA为载体的微球剂的研究进展进行综述。方法：查阅近10年来有关PLA，PLGA微球研究的国内外文献，介绍此类微球的制备方法和影响其体外释放等性质的主要因素。结果：PLA，PLGA的性质，药和折性质及微球的制备工艺等对微球的体外释放等性质均有重要的影响。结论：对以PLA，PLGA为载体制备的药物微球，有待于更进一步的研究和开发。