Yoshizawa H, Koishi M
Faculty of Pharmaceutical Sciences, Science University of Tokyo, Japan.
J Pharm Pharmacol. 1990 Oct;42(10):673-8. doi: 10.1111/j.2042-7158.1990.tb06557.x.
Fine cohesive isoprenaline HCl particles adhered to the surface of coarser potato starch particles to form interactive mixtures. These were coated with magnesium stearate by dry mixing. To check if there was a lowering of homogeneity in the latter stage, the degree of mixing was investigated before and after adding magnesium stearate. The surface appearance of magnesium stearate-coated interactive mixtures became smoother as mixing time increased or the temperature of the powder bed during mixing was raised. Ultimately, the magnesium stearate encapsulated the particles of interactive mixture. The coated interactive mixtures improved sustained release of isoprenaline HCl over the starch mixtures alone, the effect depending on the density of the magnesium stearate. Only in encapsulated mixtures was the release rate of drug decreased as the amount of magnesium stearate increased. The release of isoprenaline HCl from the interactive mixtures followed first-order kinetics. A linear relationship existed between the first-order rate constant and the reciprocal thickness of the magnesium stearate film, indicating a diffusion-controlled system with the film having some pores.
细小的粘性盐酸异丙肾上腺素颗粒附着在较粗的马铃薯淀粉颗粒表面，形成相互作用的混合物。通过干混法将这些混合物用硬脂酸镁包衣。为了检查后期均匀性是否降低，在添加硬脂酸镁之前和之后研究了混合程度。随着混合时间的增加或混合过程中粉末床温度的升高，硬脂酸镁包衣的相互作用混合物的表面外观变得更光滑。最终，硬脂酸镁包裹了相互作用混合物的颗粒。包衣的相互作用混合物比单独的淀粉混合物更能改善盐酸异丙肾上腺素的缓释，效果取决于硬脂酸镁的密度。只有在包封混合物中，药物释放速率才会随着硬脂酸镁用量的增加而降低。盐酸异丙肾上腺素从相互作用混合物中的释放遵循一级动力学。一级速率常数与硬脂酸镁膜的倒数厚度之间存在线性关系，表明该扩散控制系统中膜具有一些孔隙。
