Lin W-J, Kang W-W
School of Pharmacy, College of Medicine, National Taiwan University, Taipei 100, Taiwan.
J Microencapsul. 2003 Mar-Apr;20(2):169-77.
The aim of this study was to compare the performance of microparticles and their release properties after coating by chitosan and gelatin, respectively. All of the poly(epsilon-caprolactone) (PCL) microparticles were prepared by the hot-melt encapsulation method and indomethacin was selected as a model drug to be encapsulated. All of the coated microparticles retained their spherical shape irrespective of the type of coating material, and the particle size of coated microparticles was similar to the uncoated ones. The indomethacin encapsulation efficiency was in the range of 8.65 +/- 0.08 % - 8.81 +/- 0.04% for uncoated microparticles and 8.22 +/- 0.04% - 8.68 +/- 0.08% for coated microparticles. The release of indomethacin from uncoated microparticles followed a two-exponential release profile, where indomethacin was rapidly released within 4 h during the first release phase, after that approximately 20% of the drug was continuously and slowly released for up to 24 h in the second phase. The similar release profile was observed from coated microparticles irrespective of the times of coating and the types of coating material. Both the natural coating materials, chitosan and gelatin, efficiently reduced the initial burst release and the first phase of drug release, but did not alter the second phase of drug release. In other words, chitosan and gelatin could be used to protect the drug on the surface of microparticles from immediately contacting with the release medium and both possessed the same feature in the delay of drug release.
本研究的目的是比较微粒的性能及其分别用壳聚糖和明胶包衣后的释放特性。所有聚（ε-己内酯）（PCL）微粒均采用热熔包封法制备，并选择吲哚美辛作为模型药物进行包封。无论包衣材料的类型如何，所有包衣微粒均保持其球形，且包衣微粒的粒径与未包衣微粒相似。未包衣微粒的吲哚美辛包封率在8.65±0.08%-8.81±0.04%之间，包衣微粒的包封率在8.22±0.04%-8.68±0.08%之间。吲哚美辛从未包衣微粒中的释放遵循双指数释放曲线，即在第一个释放阶段，吲哚美辛在4小时内迅速释放，此后约20%的药物在第二个阶段持续缓慢释放长达24小时。无论包衣次数和包衣材料类型如何，从包衣微粒中观察到类似的释放曲线。壳聚糖和明胶这两种天然包衣材料均有效降低了初始突释和药物释放的第一阶段，但未改变药物释放的第二阶段。换句话说，壳聚糖和明胶可用于保护微粒表面的药物不立即与释放介质接触，并且在延迟药物释放方面具有相同的特性。
