Ichikawa H, Fujioka K, Adeyeye M C, Fukumori Y
Faculty of Pharmaceutical Sciences and High Technology Research Center, Kobe Gakuin University, Arise 518, Ikawadani-cho, Nishi-ku, 651-2180, Kobe, Japan
Int J Pharm. 2001 Mar 23;216(1-2):67-76. doi: 10.1016/s0378-5173(01)00573-7.
Ion-exchange resin (IER)--drug complexes were used as core materials to explore their capability to prepare a 100 microm-sized, highly drug-incorporated microcapsule with a prolonged drug release by the Wurster process. Diclofenac sodium was loaded into Dowex 1-X2 fractionated into 200--400 mesh and subsequently microencapsulated with two types of aqueous colloidal polymer dispersion, Aquacoator Eudragit RS30D. The mass median diameter and drug content of the microcapsules thus obtained were 98 microm and 46% with Aquacoat, and 95 microm and 50% with Eudragit RS30D, respectively. Each microcapsule was obtained at a product yield of 94%. The rate of drug release from the microcapsules was highly dependent on the encapsulating materials. For the microcapsules coated with Aquacoat, diclofenac sodium was found to be rapidly released over 4 h, even at a 25 wt% coating level because of cracks on the microcapsule surfaces resulting from the swelling stress of the drug-loaded IER cores. In contrast, significantly prolonged drug-release was achieved in the microcapsules prepared with Eudragit RS30D: even such a very low coating level as 3 wt% provided an exceptionally prolonged drug-release over 24 h. The results indicated that the use of IER along with a flexible coating material would be a feasible way to prepare a prolonged release type of microcapsules with a diameter of 100 microm and a drug content of more than 50% by the Wurster process.
离子交换树脂（IER）-药物复合物被用作核心材料，以探索其通过Wurster法制备粒径为100微米、药物高度包封且具有延长药物释放性能的微胶囊的能力。将双氯芬酸钠负载到分筛为200-400目的Dowex 1-X2中，随后用两种水性胶体聚合物分散体Aquacoat Eudragit RS30D进行微囊化。由此获得的微胶囊的质量中值直径和药物含量，使用Aquacoat时分别为98微米和46%，使用Eudragit RS30D时分别为95微米和50%。每个微胶囊的产品收率为94%。微胶囊的药物释放速率高度依赖于包封材料。对于用Aquacoat包衣的微胶囊，由于载药IER核心的溶胀应力导致微胶囊表面出现裂缝，即使在25 wt%的包衣水平下，双氯芬酸钠在4小时内也会迅速释放。相比之下，用Eudragit RS30D制备的微胶囊实现了显著延长的药物释放：即使是低至3 wt%的包衣水平也能在24小时内实现异常延长的药物释放。结果表明，将IER与柔性包衣材料一起使用是通过Wurster法制备直径为100微米、药物含量超过50%的延长释放型微胶囊的可行方法。
