维生素C溶液有氧降解动力学

建立了一种恒温高压氧药物稳定性加速试验方法, 用这种方法可在较短的时间内求得药物氧化反应的动力学参数. 以10%维生素C溶液为例, 维生素C在有氧和无氧条件下均可降解, 总的降解速率常数k_t由两部分构成: k_t＝k_an＋k_ae, k_an为无氧降解速率常数, 可表达为k_an＝A_an•exp(－E_a,an /RT); k_ae为有氧降解速率常数, 可表达为k_ae＝A_ae•exp(－E_a,ae/ RT)• .

Kinetic Studies on the Oxidative Degradation of Vitamin C Solution

An isothermal experiment with high pressure oxygen was established. The stability of 10% vitamin C solution as a model drug was studied and the kinetics parameters were obtained in a short time with the newly established experimental method. Because vitamin C degrades in both anaerobic and aerobic conditions, the total rate constant k_t can be expressed as: k_t＝k_an＋k_ae, where k_an and k_ae are the anaerobic and aerobic degradation rate constants, respectively. The k_an can be expressed as k_an＝A_an•exp(－E_a,an/RT) according to Arrhenius equation, and the k_ae was found to be k_ae＝A_ae•exp(－E_a,ae/RT)• in our experiments.