阿霉素海藻酸钠—壳聚糖微囊的释药及其体内外抗癌作用

目的：考察阿霉素海藻酸钠—壳聚糖微囊(ADM—ACM)的释药特性及其体内外抗癌作用。方法：采用乳化胶凝法制备ADM—ACM，考察微囊的释药特性。以调亡细饱的原位末端转移酶标记技术(TUNEL)及SRB活细胞染色法考察ADM—ACM的体内外抗癌活性。结果：本制备的ADM—ACM具较高的载药量，当药载比为2mg／ml，载药量达U随右。载药微囊中ADM在PBS(pH＝7．4)中突释后缓慢释放，t2h时达45％左右。体外抗癌实验表明，空白微囊对BGC—823、Bel—7402及Hela三种癌细饱株无毒性，ADM—ACM对它们的抑制作用明显优于ADM溶液。TUNEL实验显示ADM—ACM(60．85％)引起兔肢体VX2肿瘤细胞凋亡的阳性率远高于原料药(3．98％)及空白微囊(3．97％)。结论：本制备的ADM—ACM的体内外抗癌活性均显强于原料药。     

阿司匹林壳聚糖-海藻酸钠微囊处方优化与释药机制研究

目的:制备阿司匹林壳聚糖-海藻酸钠微囊(ACSPM),并研究其处方优化与释药机制。方法:设计正交试验,以包封率为指标优化ACSPM处方并制备微囊,测定其释放度并通过释放动力学模型方程拟合探讨其释药机制。结果:所得微囊大小及含量均匀,最优处方中海藻酸钠浓度、壳聚糖浓度、海藻酸钠与阿司匹林比例分别为3.0%、1.0%、1∶4,体外释放符合Higuchi方程和Peppas方程。结论:该微囊制备工艺方法简单,释药机制以药物扩散为主兼有骨架溶蚀的non-Fickian过程。     

酮咯酸氨丁三醇海藻酸钠-壳聚糖微囊的制备

以微囊的载药量和包封率为指标,采用均匀设计,结合非线性规划法优化酮咯酸氨丁三醇海藻酸钠-壳聚糖微囊的制备工艺.结果表明,按优化条件制得的微囊包封率90%,载药量44%,在水中的释药行为符合Higuchi方程.     

海藻酸钠—壳聚糖微囊的制备及载药性质的研究

目的：考察海藻酸钠－壳聚糖微囊（ACM）对荷电不同药物的载药性能，方法：采用乳化胶凝法制备了海藻酸钠－壳聚糖微囊，以阿霉素，水杨酸钠及阿昔洛韦为模型药研究其对荷电不同药物的载药性能，结果：随药载比由1g.L^1增至2g.L^1，阿霉素的包封率由67．03％增至80．46％，水杨酸钠由79．76％降至75．46％，阿昔洛韦稍有减小，由12．18％减少到10．29％，随壳聚糖浓度的增加，阿霉素及水杨酸钠的包封率呈升高趋势，分别由76．78％及75．02％升高到84．13％及78．56％。结论：本制备了圆整且分散性好的微囊，其对三种电性不同的药物具不同的包载能力，壳聚糖浓度增高可提高阿霉素及水杨酸钠的包封率。     

对乙酰氨基酚/阿拉伯胶-壳聚糖多层微囊的制备及其体外释药研究

目的:制备对乙酰氨基酚多层微囊并考察其体外释药性能和机制。方法:以阿拉伯胶和壳聚糖为囊材,以戊二醛为交联剂,使用溶液干燥法(复合乳液法)制备载药(对乙酰氨基酚)多层(阿拉伯胶-壳聚糖-阿拉伯胶-壳聚糖)微囊。通过正交试验,以阿拉伯胶溶液-二氯甲烷体积比(A)、壳聚糖用量(B)、戊二醛-成壳材料总量比例(C)为因素,包封率为指标,优选制备工艺。通过测定其在盐酸溶液中的体外累积释药率并进行释放动力学模型拟合分析其释药机制。结果:最佳工艺条件为A4:3、B0.6g、C1:3。所制备的多层微囊球形完整、光滑,囊壁较厚;突释效果不明显,药物在12h内全部释放,其体外释药机制符合Ritger-Peppas模型。结论:所制载药多层微囊突释效应小、缓释效果较好。     

奥沙普秦壳聚糖-海藻酸钠缓释微球的制备

目的：目的：选择奥沙普秦作为模型药制备壳聚糖-海藻酸钠缓释微球。方法：采用滴制法制备奥沙普秦壳聚糖-海藻酸钠缓释微球，通过正交试验设计优化了处方和工艺，考察其理化特征及体外释药行为。结果：优化处方制得的微球包封率及载药量分别为98．36％和16．26％，平均粒径为（346．6±164．1）μm；1h药物释放达到36％，随后药物的释药行为是一个缓释过程。结论：制得了载药量较大，包封率较高的奥沙普秦壳聚糖-海藻酸钠缓释微球。     

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。     

高电压静电成囊技术制备牛血清白蛋白微囊的探索

采用高电压静电成囊装置,以牛血清白蛋白(BSA)为模型药物,制备牛血清白蛋白-海藻酸钙-壳聚糖微囊,考察微囊载药情况及在pH7.4磷酸盐缓冲液中的释放行为.本法制得的微囊球形圆整,平均粒径为(38.1±15.6)um,在生理盐水中溶胀率为119%.增大投药量、壳聚糖浓度或升高CaCl2溶液pH,有利于增大微囊的载药量.BSA/海藻酸钠比例为0.5和1.0时,30min累积释放率分别为42.84%和16.30%.     

低分子肝素-壳聚糖-羧甲纤维素钠微囊的制备及释药性能

采用乳化分散交联法,制备了低分子肝素-壳聚糖-羧甲纤维素钠微囊,考察了不同处方工艺对微囊释药性能的影响.按最佳工艺制得的微囊形态圆整,粒径2～7μm,包封率和载药量分别为92.3%和6.47%,微囊释药具pH依赖性.兔体内释药实验的结果表明,低分子肝素微囊较注射液缓释效果明显.     

制备条件对丝裂霉素微囊载药量及释放度的影响

目的:筛选制备高载药量和释放性能良好的丝裂霉素微囊的条件。方法:以溶剂非溶剂法制备了丝裂霉素微囊,用高效液相色谱法和紫外分光光度法测定丝裂霉素微囊载药量及释放度。结果:随着囊材用量减少,载药量升高,释放显现突释效应;随着吐温-80用量的增加,释放度逐渐加快,直至无规律释药;随着搅拌速度的加快,载药量先增加后减少,释放度增大。结论:以正己烷、环己烷为溶剂,最佳制备工艺条件是:0.8%的乙基纤维素,4%的吐温-80,100 r.min-1的搅拌速度。     

Ionic gelation controlled drug delivery systems for gastric-mucoadhesive microcapsules of captopril

A new oral drug delivery system was developed utilizing both the concepts of controlled release and mucoadhesiveness, in order to obtain a unique drug delivery system which could remain in stomach and control the drug release for longer period of time. Captopril microcapsules were prepared with a coat consisting of alginate and a mucoadhesive polymer such as hydroxy propyl methyl cellulose, carbopol 934p, chitosan and cellulose acetate phthalate using emulsification ionic gelation process. The resulting microcapsules were discrete, large, spherical and free flowing. Microencapsulation efficiency was 41.7-89.7% and high percentage efficiency was observed with (9:1) alginate-chitosan microcapsules. All alginate-carbopol 934p microcapsules exhibited good mucoadhesive property in the in vitro wash off test. Drug release pattern for all formulation in 0.1 N HCl (pH 1.2) was diffusion controlled, gradually over 8 h and followed zero order kinetics.     

利用喷雾干燥技术制备氯雷他定透明质酸微囊和微球及其评价

目的：制备氯雷他定（LOR）透明质酸（HA）微囊和微球,并对其进行体外评价。方法：HA和聚乙二醇6000（PEG 6000）为材料,以粒径,载药量,载药率,溶解度,体外累积释放度来评价载药微囊和微球;利用DSC和XRD考察载药微囊和微球中LOR的晶型变化。结果：HA、PEG 6000和LOR的比例为16：1：2时,LOR的溶解度和溶出效果最佳。LOR微囊的水中溶解度为（23.12±0.15） μg·mL^-1,载药量为（8.07±0.44）%,载药率为（76.69±0.44）%,体外累积释放度达到（87.00±3.34）%;LOR微球的水中溶解度为（5.58±0.15） μg·mL^-1,载药量为（11.87±0.46）%,载药率为（112.78±0.46）%,体外累积释放度达到（63.16±0.63）%。晶型变化分析结果,微囊中LOR大部分以无定型状态存在,小部分以结晶状态存在;微球中LOR以无定型状态存在。结论：采用喷雾干燥法成功制备LOR-HA微囊和微球,显著改善LOR的溶解度和体外释放度的,利用此方法制备微囊（或微球）成本较低、操作简单,易于实现大规模工业化生产。     

Production of BSA-loaded alginate microcapsules: influence of spray dryer parameters on the microcapsule characteristics and BSA release

The aim of this study was to optimize the production of BSA-loaded alginate microcapsules by spray drying and to study the release of bovine serum albumin fraction V (BSA) under gastric simulated conditions. Microcapsule yield, BSA release, microcapsule size and size distribution were characterized following the application of different production parameters including inlet air temperature, inlet air pressure and liquid feed rate. The microcapsules were incubated in 0.1 N HCl and BSA release was quantified over time. The yields were higher with the pressure of 3 bar compared to 4 bar and with a feed rate of 0.45 vs. 0.2 ml s(-1). A high feed rate (0.45 vs. 0.2 ml s(-1)) allows one to obtain microcapsules with a low BSA release (p = 0.0327). The increase of the atomizer inlet temperature leads to microcapsules with a higher BSA release (p = 0.0230). A higher air pressure of 4 bar compared to 3 bar resulted in a lower microcapsule size (2.55 vs. 2.80 microm) and led to a narrower size distribution (0.92 vs. 1.07). In conclusion, the spray dryer parameters influenced the alginate microcapsule characteristics as well as subsequent protein release into a simulated gastric medium.     

Production of BSA-loaded alginate microcapsules: Influence of spray dryer parameters on the microcapsule characteristics and BSA release

The aim of this study was to optimize the production of BSA-loaded alginate microcapsules by spray drying and to study the release of bovine serum albumin fraction V (BSA) under gastric simulated conditions. Microcapsule yield, BSA release, microcapsule size and size distribution were characterized following the application of different production parameters including inlet air temperature, inlet air pressure and liquid feed rate. The microcapsules were incubated in 0.1?N HCl and BSA release was quantified over time. The yields were higher with the pressure of 3?bar compared to 4?bar and with a feed rate of 0.45 vs. 0.2?ml s^?1. A high feed rate (0.45 vs. 0.2?ml s^?1) allows one to obtain microcapsules with a low BSA release (p?=?0.0327). The increase of the atomizer inlet temperature leads to microcapsules with a higher BSA release (p?=?0.0230). A higher air pressure of 4?bar compared to 3?bar resulted in a lower microcapsule size (2.55 vs. 2.80?µm) and led to a narrower size distribution (0.92 vs. 1.07). In conclusion, the spray dryer parameters influenced the alginate microcapsule characteristics as well as subsequent protein release into a simulated gastric medium.     

Production of BSA-loaded alginate microcapsules: Influence of spray dryer parameters on the microcapsule characteristics and BSA release

The aim of this study was to optimize the production of BSA-loaded alginate microcapsules by spray drying and to study the release of bovine serum albumin fraction V (BSA) under gastric simulated conditions. Microcapsule yield, BSA release, microcapsule size and size distribution were characterized following the application of different production parameters including inlet air temperature, inlet air pressure and liquid feed rate. The microcapsules were incubated in 0.1?N HCl and BSA release was quantified over time. The yields were higher with the pressure of 3?bar compared to 4?bar and with a feed rate of 0.45 vs. 0.2?ml?s^?1. A high feed rate (0.45 vs. 0.2?ml?s^?1) allows one to obtain microcapsules with a low BSA release (p?=?0.0327). The increase of the atomizer inlet temperature leads to microcapsules with a higher BSA release (p?=?0.0230). A higher air pressure of 4?bar compared to 3?bar resulted in a lower microcapsule size (2.55 vs. 2.80?µm) and led to a narrower size distribution (0.92 vs. 1.07). In conclusion, the spray dryer parameters influenced the alginate microcapsule characteristics as well as subsequent protein release into a simulated gastric medium.     

海藻酸-壳聚糖-聚乳酸羟乙醇酸复合微球的制备及其对蛋白释放的调节

目的制备蛋白的海藻酸-壳聚糖-聚乳酸羟乙醇酸(PLGA)复合微球，以增加蛋白药物的包封率、减少突释和不完全释放。方法以牛血清白蛋白为模型药物采用修饰的乳化、醇洗法制备小粒径海藻酸微囊，再以壳聚糖孵育制得海藻酸-壳聚糖双层微囊，并进一步用PLGA包裹制得复合微球。采用微量BCA试剂盒测定蛋白浓度，考察其包封率及释放行为，改变各种制备因素调节微球的释放特性。结果复合微球粒径约30 μm，形态圆整。与单纯PLGA微球相比，包封率由60%-70%上升至80%以上。复合微球在磷酸盐缓冲液的1 h突释量由40%-50%下降至25%以下，在生理盐水中则进一步下降至5%以下。结论海藻酸-壳聚糖-PLGA复合微球提高了蛋白药物的包封率，减少了药物的突释，并可通过调节PLGA比例调节药物的释放。     

Preparation and in vitro evaluation of polylactic acid-mitomycin C microcapsules

Abstract

An emulsion method was developed for the incorporation of water-soluble mitomycin C into polylactic acid biodegradable microcapsules. With an average particle size of about 95 μm, microcapsules with a desired loading of from 3.65 to 13.80 per cent were prepared. These microcapsules, which contained both crystalline and finely dispersed drug particles, showed a dose-dependent drug release pattern with microcapsules of higher drug loading having a faster release rate than those of lower drug loading. Effective sterilization of the microcapsules for parenteral use was achieved by ⁶⁰Co γ-ray irradiation, which did not affect the microcapsule structure, release rate or drug stability. Mitomycin C showed dose-dependent antiproliferative activity against the growth of the K562 human erythroleukaemia cells. The microencapsulated dosage form of mitomycin C was found to enhance the drug's activity through sustained drug release. In experiments where drug concentrations in the cell medium were reduced according to the drug's biological half-life, the microcapsule systems showed a distinct advantage over the non-capsulated dose for the kinetic inhibition of K562 cell growth.     

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。     

Microencapsulation using poly(DL-lactic acid). I: Effect of preparative variables on the microcapsule characteristics and release kinetics

Poly(DL-lactic acid) (DL-PLA, molecular weight 20,500) microcapsules containing phenobarbitone (PB) as a reference core were prepared using a water/oil (W/O) emulsion system. Surface morphology, particle size and 'encapsulation efficiency' of the microcapsules prepared using different preparative variables have been investigated. Buffer pH 9 was used as a dissolution medium to determine the affect of preparative variables on the release rate from these microcapsules. With an increase in temperature of evaporation the microcapsule surface became increasingly irregular and porous, due to deposition of phenobarbitone crystals near the vicinity of the microcapsule surface leading to rapid release of the core. The normalized release rate was found to increase exponentially with an increase in the temperature of evaporation. Microcapsule morphology was also severely affected due to differences in polymer concentration in the disperse phase solvent. With the increase in polymer concentration, the microcapsule surface was found to be increasingly irregular and non-continuous, due to rapid precipitation of the polymer. Increased polymer concentrations also increased mean microcapsule diameter. The release rate increased with the increase in polymer concentration due to surface defects and did not exhibit a straight line correlation. When core loading was very high (e.g. C:P, 2:1 and 1:1), crystals of phenobarbitone appeared at the surface and these caused a very rapid burst effect. However, microcapsules containing a lower phenobarbitone content were found to follow t1/2 dependent release. The encapsulation efficiency was not seriously affected due to variations in temperature of preparation and polymer concentration. However, with the decrease in initial core loading the encapsulation efficiency of microcapsules was found to be reduced.