Otsuka M, Kaneniwa N, Kawakami K, Umezawa O
School of Pharmaceutical Sciences, Showa University, Tokyo, Japan.
J Pharm Pharmacol. 1991 Apr;43(4):226-31. doi: 10.1111/j.2042-7158.1991.tb06673.x.
The effects of tableting pressure on hydration kinetics of types I and II theophylline anhydrate tablets at 95% relative humidity, 35 degrees C, have been studied by using various kinetic equations. Relations between tablet expansion and hydration were studied. Samples of 2 cm diameter tablets (1 g) were compressed at 5, 10 and 20 MPa. The hydration of types I and II tablets decreased with increased tableting pressure. The time required for 50% hydration of 2 cm diameter tablets, compressed at various pressures suggests that the tablet hydration rate was affected by the tableting pressure. Types I and II tablets expanded 11.37-16.75% in volume during hydration to the monohydrate. The thickness expansion of the tablets exceeded the diameter expansion as the tablet structure was not uniform owing to the orientation of particles during the compression. The final expansion ratio of the tablets increased with increased tableting compression pressure. The Hancock Sharp constant (m) and fitting of the kinetic data to a suitable model suggested that the hydration of theophylline anhydrate tablets followed the two-dimensional phase boundary equation (type I tablets) or the three-dimensional phase boundary equation (type II tablets).
通过使用各种动力学方程，研究了压片压力对I型和II型无水茶碱片剂在95%相对湿度、35℃条件下水合动力学的影响。研究了片剂膨胀与水合之间的关系。将直径2 cm的片剂样品（1 g）在5、10和20 MPa压力下进行压制。I型和II型片剂的水合作用随压片压力的增加而降低。不同压力下压制的直径2 cm片剂达到50%水合所需的时间表明，片剂水合速率受压片压力的影响。I型和II型片剂在水合形成一水合物的过程中体积膨胀了11.37 - 16.75%。由于压制过程中颗粒的取向，片剂结构不均匀，片剂的厚度膨胀超过了直径膨胀。片剂的最终膨胀率随压片压力的增加而增大。汉考克-夏普常数（m）以及动力学数据与合适模型的拟合表明，无水茶碱片剂的水合作用遵循二维相边界方程（I型片剂）或三维相边界方程（II型片剂）。
