Teng Xiao Wei, Cutler David C, Davies Neal M
Department of Pharmaceutical Sciences, College of Pharmacy, Washington State University, P.O. Box 646534, Pullman, WA 99164-6534, USA.
Int J Pharm. 2003 Jun 18;259(1-2):129-41. doi: 10.1016/s0378-5173(03)00226-6.
Mometasone furoate (MF) is a synthetic glucocorticoid. There is little information available on the stability of MF and no degradation products have been unequivocally identified. Thus, the primary objective of this study was to characterize the degradation of MF, qualitatively and quantitatively. Stability of MF decreased with increasing pH (>4) and decreasing ionic strength in aqueous media. The chemical stability of MF in aqueous systems was significantly dependent on pH. MF appeared to be stable at pH < 4 but degraded to four products at higher pH. The degradation of MF in aqueous solutions follows pseudo-first-order kinetics and involved a series of parallel and consecutive reactions. The turnover of MF and its products appears to be catalyzed by the hydroxide ion. The pH dependence of these reactions should be considered, when formulating or extemporaneously compounding MF formulations. An optimal pH of stability was below pH 4. The changes in pH, however, do not appear to be the only factor of importance, since an increase in ionic strength and buffer concentration displayed a stabilizing effect on this glucocorticoid in the buffers tested. Trace metal ions are unlikely to be involved in degradation of MF in aqueous solution.
糠酸莫米松（MF）是一种合成糖皮质激素。关于MF稳定性的信息很少，且尚未明确鉴定出降解产物。因此，本研究的主要目的是定性和定量地表征MF的降解情况。在水性介质中，MF的稳定性随pH值升高（>4）和离子强度降低而降低。MF在水性体系中的化学稳定性显著取决于pH值。MF在pH<4时似乎稳定，但在较高pH值下会降解为四种产物。MF在水溶液中的降解遵循准一级动力学，涉及一系列平行和连续反应。MF及其产物的周转似乎由氢氧根离子催化。在配制或临时调配MF制剂时，应考虑这些反应对pH值的依赖性。稳定性的最佳pH值低于4。然而，pH值的变化似乎并非唯一重要的因素，因为在所测试的缓冲液中，离子强度和缓冲液浓度的增加对这种糖皮质激素具有稳定作用。痕量金属离子不太可能参与MF在水溶液中的降解。
