Kassem A A, Tawfik A S, Bayoma S M, Geneidi A S, El-Sharkawy A M
Pharmazie. 1981 Dec;36(12):827-30.
Dissolution rates and apparent solubilities of forms I, II and III of Sulfamethoxypyridazine (1) and forms I and II of sulfisomidine (2) were determined in water at 37 degrees C. The ratios of apparent solubilities of I:II:III for 1 forms and I:II for 2 forms were 1:1.18:1.25 and 1:1.32 respectively. Upon long contact of 2 with water the ratio of II:I decreased. This has been attributed to gradual transformation of 2 from form II to I. Gastrointestinal absorption of form III of 1, in human volunteers, was studied in comparison with the more stable form I. The same study was carried out on forms I and II of 2. Data were correlated and expressed in availability rate constants (K1), applying the one compartment open: model. This and other parameters show that form III of 1 is 1.4 times as much absorbed as form I, and that the availability of the metastable form II of 2 is 1.2 times as much absorbed as the stable form I.
测定了磺胺甲氧嗪（1）的Ⅰ、Ⅱ、Ⅲ型及磺胺异嘧啶（2）的Ⅰ、Ⅱ型在37℃水中的溶出速率和表观溶解度。1型的Ⅰ:Ⅱ:Ⅲ表观溶解度之比以及2型的Ⅰ:Ⅱ表观溶解度之比分别为1:1.18:1.25和1:1.32。2与水长时间接触后，Ⅱ:Ⅰ的比例降低。这归因于2从Ⅱ型逐渐转变为Ⅰ型。在人体志愿者中，研究了1的Ⅲ型与更稳定的Ⅰ型相比的胃肠道吸收情况。对2的Ⅰ型和Ⅱ型也进行了同样的研究。数据进行了关联，并应用单室开放模型以有效速率常数（K1）表示。该参数及其他参数表明，1的Ⅲ型吸收量是Ⅰ型的1.4倍，2的亚稳Ⅱ型的吸收利用率是稳定Ⅰ型的1.2倍。
