サリチル酸フェニルのエタノール性水溶液中での安定性

概要

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The stability and degradation pathways of phenyl salicylate (PS) in 50 v/v% aqueous ethanol were investigated over the pH range of 3.2-8.4. The experiments were performed at three different temperatures (5,23 and 50℃) for four months by the use of high performance liquid chromatography. The degradation of PS was observed as a pseudo first-order kinetics not only in the alkaline region but in the acidic region and shown to proceed via transesterification (k_1) and hydrolysis (k_2) processes. The transesteified product, ethyl salicylate (ES), further underwent hydrolysis (k_3)(k_1>k_2>k_3). On the basis of kinetic studies, it was found that the degradation rate of PS decreased with decreasing pH and temperature. The half-lives of PS at pH 6.3 were 6.6d (50℃), 178d (23℃) and 2934d (5℃), respectively, and PS was stable at below ca. pH 4. On the other hand, PS in 100% ethanol also underwent the breakdown to ES by k_1 process and its half-lives were 2.5d (50℃), 31.5d (23℃) and 257d (5℃), respectively. The present results is useful for the integrity of pharmaceutical formulations and delivery profiles.
公益社団法人日本薬学会の論文
1996-01-25