Cornejo J, Hermosin M C, White J L, Peck G E, Hem S L
J Pharm Sci. 1980 Aug;69(8):945-8. doi: 10.1002/jps.2600690821.
Degradation of hydrocortisone in attapulgite suspensions was monitored by high-pressure liquid chromatography and UV spectrophotometry. The rate of oxidative degration of hydrocortisone was accelerated significantly in the presence of attapulgite. In addition, degradation appeared to be composed of two apparent first-order reactions rather than the single apparent first-order degradation reaction observed for hydrocortisone solutions. However, the same degradation products were obtained in both hydrocortisone solutions and attapulgite suspensions, indicating that interaction with attapulgite did not alter the degradation pathway. Kinetic and adsorption studies suggested that hydrocortisone is adsorbed weakly by attapulgite and undergoes oxidative degradation, which is catalyzed by adsorbed iron oxides or hydroxides as well as by structural ferric iron at the clay surface. Since clay minerals generally contain surface ferric iron, the potentiala for accelerating the oxidative degradation of drugs should be considered whenever clays and drugs are combined.
通过高压液相色谱法和紫外分光光度法监测了氢化可的松在凹凸棒石悬浮液中的降解情况。在凹凸棒石存在的情况下，氢化可的松的氧化降解速率显著加快。此外，降解似乎由两个明显的一级反应组成，而不是氢化可的松溶液中观察到的单一明显一级降解反应。然而，氢化可的松溶液和凹凸棒石悬浮液中得到了相同的降解产物，这表明与凹凸棒石的相互作用并未改变降解途径。动力学和吸附研究表明，氢化可的松被凹凸棒石弱吸附并发生氧化降解，其由吸附的铁氧化物或氢氧化物以及粘土表面的结构铁催化。由于粘土矿物通常含有表面铁，因此当粘土与药物混合时，应考虑加速药物氧化降解的可能性。
