Chiao C S, Price J C
School of Pharmacy, Northeast Louisiana University, Monroe 71209.
Pharm Res. 1989 Jun;6(6):517-20. doi: 10.1023/a:1015980809952.
A three-phase suspension process was used for the preparation of gelatin beadlets containing succinylsulfathiazole. When the beadlets were hardened with 10% formalin at 5 degrees C for varying periods of time up to 24 hr, the 6-hr hardening time gave the slowest release rate. Drug release rate from gelatin beadlets was slower in simulated gastric fluid (SGF) than in simulated intestinal fluid (SIF) but the sustained effect was too limited to be useful for most applications. When the hardened gelatin beadlets were coated with cellulose acetate butyrate (CAB) by an emulsion-solvent evaporation method, a more pronounced sustained effect and a nearly zero-order release were found in SIF. The effects of the amount of gelatin used, the amount of CAB employed, and the length of hardening time on drug release were investigated. The treatment of gelatin beadlets with formalin reduced the swelling action of gelatin in aqueous medium. A nonzero-order drug release rate was observed when the gelatin swelled sufficiently to rupture the CAB coating. The drug release rate can be adjusted by using different ratios of hardened gelatin beadlets and CAB coating in which the gelatin enhances the release rate and the CAB serves as a barrier.
采用三相悬浮法制备含琥珀酰磺胺噻唑的明胶微丸。当微丸在5℃下用10%甲醛硬化不同时间（最长24小时）时，6小时的硬化时间释放速率最慢。明胶微丸在模拟胃液（SGF）中的药物释放速率比在模拟肠液（SIF）中慢，但持续效果过于有限，对大多数应用来说并无用处。当通过乳液 - 溶剂蒸发法用醋酸丁酸纤维素（CAB）包衣硬化后的明胶微丸时，在SIF中发现了更显著的持续效果和近乎零级的释放。研究了明胶用量、CAB用量和硬化时间长度对药物释放的影响。用甲醛处理明胶微丸降低了明胶在水性介质中的溶胀作用。当明胶充分溶胀以破裂CAB包衣时，观察到非零级药物释放速率。通过使用不同比例的硬化明胶微丸和CAB包衣可以调节药物释放速率，其中明胶提高释放速率，而CAB起到屏障作用。
