Govender T, Dangor C M, Chetty D J
Pharmacy Department, University of Durban-Westville, South Africa.
J Microencapsul. 1997 Jan-Feb;14(1):1-13. doi: 10.3109/02652049709056463.
The air suspension technique was employed to prepare Eudragit RS30D-coated controlled-release pellets of salbutamol. Drug release in dissolution studies can be dependent on the dissolution method and medium used. Thus, the aim of this study was to investigate the influence of various dissolution methods and dissolution medium pH values on drug release from a batch of pellets which displayed controlled drug-release characteristics over an 8-h period in deionized water using the rotating basket method. In vitro testing using the official USP XXII (rotating basket and rotating paddle) and non-official (rotating bottle) methods showed drug release to be independent of the method used. The prepared pellets displayed pH-dependent drug-release characteristics when tested in hydrochloric acid (pH 1.5), phosphate buffer (pH 6.8) and deionized water (pH 7.2). Also, in vitro testing, which exposed the pellets to a changing pH gradient that simulated the gastrointestinal pH conditions following oral administration, was used to confirm the drug-release characteristics. The results showed controlled-release characteristics to be maintained, with the drug being released over an 8-h period. Scanning electron microscopic evaluation proved useful in the elucidation of the physical characteristics of the controlled-release pellets as well as in the identification of a possible mode of drug transfer into the dissolution medium.
采用空气悬浮技术制备了沙丁胺醇的Eudragit RS30D包衣控释微丸。溶出度研究中的药物释放可能取决于所使用的溶出方法和介质。因此，本研究的目的是研究各种溶出方法和溶出介质pH值对一批微丸药物释放的影响，这批微丸在去离子水中使用转篮法在8小时内显示出控释特性。使用美国药典XXII官方方法（转篮法和转桨法）和非官方方法（转瓶法）进行的体外测试表明，药物释放与所使用的方法无关。在盐酸（pH 1.5）、磷酸盐缓冲液（pH 6.8）和去离子水（pH 7.2）中测试时，制备的微丸显示出pH依赖性药物释放特性。此外，体外测试将微丸暴露于模拟口服给药后胃肠道pH条件的变化pH梯度中，以确认药物释放特性。结果表明，控释特性得以维持，药物在8小时内释放。扫描电子显微镜评估被证明有助于阐明控释微丸的物理特性以及确定药物向溶出介质转移的可能模式。
