肝动脉栓塞米托蒽醌乙基纤维素微球的研究

利用正交实验设计法,优选适用于肝动脉栓塞的米托蒽醌乙基纤维素微球制备条件和工艺;采用动态透析法研究了该微球的体外释药规律;根据混悬液的稳定性理论,优选并制备了适于临床肝动脉介导栓塞使用的米托蒽醌乙基纤维素微球混悬注射液。结果表明∶在优化工艺条件下制得的米托蒽醌乙基纤维素微球外形圆整,球径在40～200μm范围内的占总数的91.9%,平均球径为110.24±38.19μm;包封率为55.6%;载药量为12.5%;体外释药符合单指数模型,释药方程为lg(Y_∞-Y)=-0.116t-1.198×10^-3(γ=0.9992,t₅₀=2.6h);其混悬液适于临床应用。用狗进行的实验表明肝血药浓度高,平均驻留时间比注射剂长2.45倍。     

肝动脉栓塞用顺铂白蛋白微球的研究

按正交设计筛选乳化热固化法制备顺铂白蛋白微球的最佳工艺,并对影响微球粒径大小和体外释药速率的诸多因素进行了研究。该微球粒径范围为50.8～256μm。平均粒径为148.46μm,药物含量为51.16%(W/W)。兔肝动脉栓塞后,与对照组相比铂的分布半衰期延长336%,消除半衰期延长123%,体内最高血浓仅为对照组的30%。肝组织顺铂量显著增加(P<0.01),肾组织药物量明显降低(P<0.05),体内外相关性研究表明顺铂白蛋白微球体外累积溶出百分率与兔体内药物吸收分数呈显著相关(P<0.01)。     

关节腔内注射用氟比洛芬明胶微球

目的:制备关节腔注射用氟比洛芬明胶微球。方法:按均匀设计法筛选乳化冻凝法制备氟比洛芬明胶微球(FP GMS)的最佳制备工艺。结果:微球粒径范围为2.5～12.3μm,平均粒径为7.53μm,氟比洛芬含量为5.02%(w/w)。其体外释药符合Higuchi方程,稳定性实验表明,FP-GMS的稳定性良好,兔关节腔内注射后,与溶液剂对照组相比氟比洛芬体内平均驻留时间(MRT)显著延长(P<0.01),峰时比对照组延长2.03倍,峰浓度比对照组减小5.57倍。体内外相关性研究表明,FP-GMS体外累积溶出百分率与兔体内药物吸收分数呈显著相关(P<0.01)。结论:本法制备的氟比洛芬明胶微球粒径分布集中,粒径大小符合设计要求,体内外释药结果表明氟比洛芬明胶微球具有明显的缓释作用。     

盐酸川芎嗪肺靶向微球的研究

用乳化法制备盐酸川芎嗪明肢微球,优化了工艺。对微球的外观、粒径与其分布、含量、体外释药、稳定性及体内分布等进行研究。结果表明平均粒径为12.65μm,粒径范围5.0～24.9μm占总数的87.5%,球内含药量平均为16.49%±0.49%(n=3),冰箱或室温放置稳定,体外释药符合一级动力学规律,释药t_1/2比原药延长约5倍。小鼠静注微球后20 min,在肺内的相对分布百分率明显高于其它组织与血液,与溶液对照组相比,提高近6倍。     

左炔诺孕酮-聚3-羟基丁酸酯缓释微球的研究

目的：优化制备工艺,用可生物降解的成球材料制备缓释并有优良抗生育效果的左炔诺孕酮-聚3-羟基丁酸酯微球。方法：以均匀设计优化微球的液中干燥法制备工艺,用DTA确证含药微球的形成,对微球的外观、粒径、载药量、体外释药、稳定性及小鼠体内抗生育等进行了研究。结果：微球平均粒径为64 μm,(28.7～85.8) μm的微球占总数90％以上,微球中氯仿残留量低于0.001％,体外释药符合Higuchi方程,释药T_1/2比原药延长约1.8倍,4,25及40℃(RH 75%)放置3个月稳定。对小鼠具有抗生育效果。结论：微球的制备工艺满意,与原药相比,微球对小鼠有明显的缓释、延长抗生育时间和降低毒性的作用。     

新型可降解聚酯材料地西泮缓释微球的研制

目的　优化制备工艺,用新型的生物可降解材料聚羟基丁酸酯—羟基戊酸酯共聚物（PHBV）与D,L-聚乳酸（PLA）共混物为基材制备以地西泮（diazepam,DZP）为模型药物的缓释微球（MS）。方法　用正交设计优化微球制备工艺,用扫描电镜（SEM）观察微球表面形态。对微球粒径及其分布、体外释药、稳定性及在动物体内药动学进行了测定。结果　微球平均粒径为(20.45±4.50) μm,粒径在15.5～35.2 μm占总数88%以上。载药量为(16.95±0.80)%,包封率为(69.68±1.13)%;体外释药方程为Q=2.7027t+13.50(γ=0.9827),动物体内实验表明,微球的血药浓度-时间曲线下面积AUC是溶液对照组的2.35倍,平均驻留时间MRT是对照组的3.62倍。微球在冰箱4℃与室温（20～25℃）条件下性质稳定。结论　微球制备工艺稳定,与DZP针剂相比,具有明显缓释作用。     

肺靶向利福平聚乳酸微球的研究

在单因素考察的基础上进行正交试验设计,筛选出肺靶向利福平聚乳酸微球的最佳制备工艺条件;利用桨板法研究了微球的体外释药规律;考察了微球在不同温度下的稳定性;用新西兰兔为实验对象,研究了利福平聚乳酸微球的体内药动学及组织药物分布。结果制得的微球形态圆整,粒径在5～15μm范围内的占总体积的86.54%,微球平均粒径为9.00±4.08μm;包封率为31.9%;载药量为16.0%;体外释药方程为Q=20.77+10.12T_1/2(γ=0.9892);微球在冰箱4℃和室温(20～25℃)条件下性质稳定;体内实验表明微球具有长效和肺靶向双重作用。     

顺铂壳聚糖微球的制备及特性研究

对顺铂壳聚糖微球的制备、载药量、大小及分布、形态及表面状态、体外释放及降解性进行了研究。微球用乳化-化学交联技术制备,平均粒径为74.80μm,顺铂含量为20.83%±0.36%。电镜扫描显示,微球球形圆整,表面粗糙。生理盐水中放置1h微球轻微溶胀,其体外释药符合一级方程,微球经⁶⁰Co辐射灭菌达到无菌要求。犬肝动脉栓塞后一个月,病理切片可见栓塞区仍有壳聚糖微球存在。     

肝靶向米托蒽醌白蛋白微球的研究

用乳化—热固化法制备了米托蒽醌白蛋白微球,并对其形态、大小及其分布、微粉学性质、载药性能、体外释药、稳定性和体内分布进行了研究。结果表明,该载药微球的平均算术径为0.99μm,平均表面径为1.24μm,平均容积径为1.44μm;表观载药量为2.558%±0.101%;有效载药量为1.503%±0.127%;包封率为92.82%±4.60%;体外释药符合双相动力学规律,释药方程为1-Q=0.6428e^-0.2132t+0.3988e^-000150t(γ₁=-0.9951,γ₂=-0.9982);T_1/2α=3.250h,T_1/2β=461.7h;室温放置3个月,微球形态、药物含量等均无明显变化。HPLC测定表明,小鼠尾iv该微球20min内即有77.6%±1.38%的药物浓集于肝脏,具有明显的肝靶向性。提示米托蒽醌白蛋白微球有可能提高米托蒽醌的抗肝癌效果和降低其全身毒副作用。     

米托蒽醌肝动脉栓塞羧甲基淀粉微球的研究

为进一步研究栓塞微球的制备工艺、体外释药规律及药动学与药效学之间的关系,以米托蒽醌为模型药物、羧甲基淀粉钠为载体材料、对苯二甲酰氯为交联剂,经均匀设计法优化了制备空白羧甲基淀粉微球的工艺,用吸附法制备了米托蒽醌载药羧甲基淀粉微球。对载药微球的理化性质进行了研究。并以家兔为模型动物研究了载药微球经肝动脉栓塞给药后的药代动力学情况。结果表明:载药微球的平均算术粒径为75.71μm,含药量为13.21%,吸水膨胀率为71.94%,体外释药符合单指数模型。药动学研究表明,米托蒽醌制成微球经肝动脉栓塞给药后可延长药物驻留于靶位的时间,提示有利于肝癌的治疗。     

Preparation and characterization of a biodegradable drug targeting system for anticancer drug delivery: Microsphere-antibody conjugate

Targeted delivery of anticancer drugs is one of the most actively pursued goals in anticancer chemotherapy. A major disadvantage of anticancer drugs is their lack of selectivity for tumour tissue, which causes severe side effects and results in low cure rates. Any strategy by which a cytotoxic drug is targeted to the tumour, thus increasing the therapeutic index of the drug, is a way of improving cancer chemotherapy and minimizing systematic toxicity. This study covers the preparation of the gelatin microsphere (GM)-anti-bovine serum albumin (anti-BSA) conjugate for the development of a drug targeting approach for anticancer drug delivery. Microspheres of 5% (w/v) gelatin content were prepared by crosslinking with glutaraldehyde (GTA) at 0.05 and 0.50% (v/v) concentration. Microspheres were in the size range of 71–141 μm. The suitability of these microspheres as drug carriers for anticancer drug delivery was investigated in vitro by studying the release profiles of loaded methotrexate (MTX) and 5-fluorouracil (5-FU) and the cytotoxicities on cancer cell lines. The in vitro MTX release profiles (～22–46% released in 24 h depending on the amount of GTA used) were much slower compared to 5-FU (～42–91% released in 24 h). Both drugs demonstrated an initial fast release, which was followed by gradual, sustained drug release. The MTT cytotoxicity test results of GMs loaded with 5-FU and MTX showed ～54–70% and ～52–67% cytotoxicities in 4 days. In general, incorporation of MTX and 5-FU in microspheres enhanced the cytotoxic effect in a more prolonged manner compared to the free drugs. Gelatin micospheres were chemically conjugated to anti-BSA and the antigen–antibody activities were studied by immunofluorescence. Results indicated ～80% binding with conjugated anti-BSA and BSA-FITC. Based on their low cytotoxicity and the high antigen binding efficiencies, anti-BSA conjugated gelatin microspheres could be suitable targeted drug carrier systems for selective and long-term delivery of anticancer drugs to a specific body compartment (i.e. bladder cancer).     

Formation and Characterization of Cisplatin-Loaded Poly(benzyl 1-glutamate) Microspheres for Chemoembolization

Chemoembolization using microspheres of 100- to 200-µm is a useful way to treat primary and secondary hepatic tumors. In a search for a better embolic material, we described in detail the preparation and characterization of a poly(benzyl 1-glutamate) (PBLG) microspheres containing cisplatin (CDDP). We determined the optimal experimental conditions to produce spherical free-flowing microspheres that were able to release drug content (44% [w/w] CDDP) in a sustained manner. We found that solvent viscosity played a key role in determining the resulting microsphere characteristics. Microscopic studies showed that increasing the polymer concentration (to 10% [w/v]) and the viscosity of the organic phase produced microspheres with uniform drug distribution. Increasing polymer concentration also markedly improved drug incorporation efficiency. In vitro release studies revealed that the release of CDDP was a function of drug loading; microspheres with a higher amount of entrapped CDDP had a slower release rate. This observation and the fact that CDDP/ PBLG microspheres did not show burst effect at higher loading is ascribed to the formation of uniformly distributed drug crystal networks within the polymer matrix. The favorable properties of the CDDP/PBLG system warrants its further evaluation on experimental animal models for the treatment of hepatic tumors.     

Formulation and testing of vancomycin loaded albumin microspheres prepared by spray-drying

Microparticles are widely employed as carriers of biologically active compounds with many possible applications. For targeted drug delivery and sustained release purposes, biopolymers (i.e. polysaccharides and proteins) have been proposed. In this study, microsphere formulations of vancomycin were prepared by the spray-drying method. Bovine serum albumin (BSA) was used as a polymer matrix and was cross-linked with glutaraldehyde after microsphere preparation. The product yield obtained from the spray-drying method was ～75%. The mean particle size was 5?±?1.6?µm, with the majority of particles between 4 and 8?µm. The extent of cross-linking affected the release of vancomycin from microspheres. Moreover, both rate and extent of vancomycin release from microspheres decreased with increasing glutaraldehyde concentration. Encapsulation of vancomycin did not alter the bioactivity of the drug and it was more effective in killing Staphylococcus aureus than the solution form.     

Formulation and in vitro/in vivo evaluation of terbutaline sulphate incorporated in PLGA (25/75) and L-PLA microspheres

Terbutaline sulphate (TBS) is widely used in the treatment of bronchial asthma, chronic bronchitis and emphysema. Because of its short biological half life and dosing schedule, a long acting TBS formulation is required to improve patient compliance. The objective of this study was to develop a TBS containing biodegradable microsphere formulation. Poly(D, L-lactide-co-glyco-lide) (PLGA) and poly(L-lactic acid) (L-PLA) were chosen as matrix materials. A solvent evaporation method was used for preparation of microspheres. Surface morphology, particle size distribution and encapsulation efficiency were investigated. In vitro release studies were performed in pH 7.4 phosphate buffer. In vivo distribution of microspheres were studied in the Swiss albino male mice. All microspheres were spherical in shape and had a porous surface with mean diameters of 9–21 μm. The encapsulation efficiency was influenced by the polymer type, but not the molecular weight. About 90% of the initial amount was trapped in PLGA microspheres, and the remainder was on the surface. In the case of L-PLA, 50% of the total drug was associated with the surface of microspheres. The in vitro release pattern was biphasic characterized by an initial burst phase followed by a slower phase. The L-PLA microspheres released ～92% of the initial payload in 72 h. On the other hand, TBS release was increased with an increase in the molecular weight of PLGA. Biodistribution of L-PLA microspheres was characterized by an initially high uptake (35%) by the lungs. All these results suggest that L-PLA and PLGA microspheres have the potential to be used for passive lung targeting.     

Effect of Drug (Core) Particle Size on the Dissolution of Theophylline from Microspheres Made from Low Molecular Weight Cellulose Acetate Propionate

Three particle sizes (450, 120, and 5 µm) of theophylline were encapsulated in low molecular weight cellulose acetate propionate (intrinsic viscosity, 1.08 dl/g) by the solvent evaporation method. The theoretical drug content for all the batches of microspheres was 50% (w/w). Particle size analysis revealed that about 50% of the microspheres containing the large theophylline crystals (average length of 450 µm) were greater than 500 µm in diameter, whereas only about 35% of the microspheres containing the medium drug crystals (average length of 120 µm) were greater than 500 µm in diameter. The drug content of the larger microspheres prepared from the large drug crystals and the medium drug crystals was much greater than the theoretical drug content (50%, w/w); however, the drug content of all the batches of microspheres containing micronized drug was close to 50% (w/w). Release of the drug in simulated intestinal fluid was very rapid from microspheres containing large and medium drug crystals, while release was slower and more predictable from microspheres made from micronized drug.     

避孕药微球制备工艺的研究

采用可生物降解醚酯嵌段共聚物poly(ethylglycol—lactide)(简称PEGL)为载体,以溶剂蒸发法制备了避孕药左旋18-甲基炔诺酮(LNG)和雌二醇(E₂的PEGL微球。筛选出最佳制备微球的工艺,微球的平均容积径约为30μm,包封率为75～82%。体外释药试验结果表明,避孕药微球能减慢主药的释放,且其释放速度随载药量的降低而减慢。避孕药微球可使小鼠抗生育时间维持6个月以上,证实该微球具有缓释延效的作用。