Pflegel P, Schöbel H, Klaus T, Raguse U
Sektion Pharmazie, Ernst-Moritz-Arndt-Universität Greifswald.
Pharmazie. 1990 Apr;45(4):266-7.
Solubility of 18 drugs used in rectal therapy in molten suppository base, (Massa suppositoriorum 15, Pharmacopeia of the G.D.R. Rosupol U, 37 degrees C) is determined. Separation of drug-saturated base from drug cristals is carried out in an air-heated centrifuge followed by a partition step between petroleum ether and an aqueous medium and photometrical determination of drug concentration. The procedure leads to results with relative standard deviation of 2% (medium value of 18 drugs). The investigation gave solubility values in the range between 0.002% (theobromine) and 26% (lidocaine), whereas benzoate, phenobarbital sodium and procaine hydrochloride are completely insoluble. Sodium salicylate has an unexpected high solubility (0.48%). The solubility is temperature depended and thus the solubility enthalpy can be determined. Relations between structure and solubility are discussed for pyrazolin-5-ones and purines. A correlation between solubilities in the base and in aqueous buffer (phosphate, pH 7.4) does not exist in the series studied.
测定了18种直肠治疗用药在熔融栓剂基质（东德药典Rosupol U中的栓剂基质15，37℃）中的溶解度。在空气加热的离心机中进行药物饱和基质与药物晶体的分离，随后进行石油醚与水相介质之间的分配步骤，并通过光度法测定药物浓度。该方法得到的结果相对标准偏差为2%（18种药物的中值）。研究得出的溶解度值在0.002%（可可碱）至26%（利多卡因）之间，而苯甲酸盐、苯巴比妥钠和盐酸普鲁卡因完全不溶。水杨酸钠具有意外的高溶解度（0.48%）。溶解度取决于温度，因此可以测定溶解焓。讨论了吡唑啉-5-酮和嘌呤的结构与溶解度之间的关系。在所研究的系列中，药物在基质中的溶解度与在水性缓冲液（磷酸盐，pH 7.4）中的溶解度之间不存在相关性。
