Song S Z, Cardinal J R, Kim S H, Kim S W
J Pharm Sci. 1981 Feb;70(2):216-9. doi: 10.1002/jps.2600700226.
Progesterone release from monolithic devices prepared from various copolymers of poly(hydroxyethyl methacrylate) and poly(methoxyethoxyethyl methacrylate) or poly(methoxyethyl methacrylate) was examined. In general, plots of the fraction of drug released versus (time)1/2 were linear during the early stages of drug release. This behavior is similar to that found for drugs released from hydrophobic polymers such as polydimethyl siloxane. However, for some release curves using the hydrogels, a breakpoint appeared during the early stages of drug release. These breakpoints were due to the effects of water absorption by these polymers. From analyses of permeability coefficients, it was demonstrated that release rates also were dependent on the initial drug load and the equilibrium water content of the polymer. These conclusions were verified from cross-membrane diffusion studies on films depleted of their initial drug load. In conjunction with this work, the aqueous solubility of progesterone was determined by several methods; an average value of 38 micrograms/ml at 23 degrees was obtained.
研究了由聚（甲基丙烯酸羟乙酯）与聚（甲氧基乙氧基乙基甲基丙烯酸酯）或聚（甲氧基乙基甲基丙烯酸酯）的各种共聚物制备的整体式装置中孕酮的释放情况。一般来说，在药物释放的早期阶段，药物释放分数与（时间）1/2的关系图呈线性。这种行为与从疏水性聚合物如聚二甲基硅氧烷中释放的药物相似。然而，对于一些使用水凝胶的释放曲线，在药物释放的早期阶段出现了一个转折点。这些转折点是由于这些聚合物吸水的影响。通过对渗透系数的分析表明，释放速率还取决于聚合物的初始药物负载量和平衡含水量。这些结论通过对耗尽初始药物负载量的薄膜进行跨膜扩散研究得到了验证。结合这项工作，通过几种方法测定了孕酮的水溶性；在23℃时得到的平均值为38微克/毫升。
