高效液相色谱法同时测定氯地乳膏中氯霉素与地塞米松的含量及其稳定性研究

Determination of chloramphenicol and dexamethasone in chloramphenicol dexamethasone ointment by HPLC and its stability

目的 测定氯地乳膏中氯霉素与醋酸地塞米松的含量及其稳定性考察。方法 采用HPLC法，流动相为甲醇．水（70：30），检测波长240nm，流速0．7ml·min^-1。测定氯地乳膏的含量，并以经典恒温法考察氯霉素、醋酸地塞米松含量变化。结果氯霉素和醋酸地塞米松分别在50．01～300．06mg·L^-1，1．25～7．5mg·L^-1范围有良好的线性关系。平均回收率为（97．12±3．70）％、（95．40±3．69）％。氯霉素、醋酸地塞米松降解均遵循一级动力学反应，10℃时，t0.5分别为69、19d。结论 方法方便、快速、准确，可作为该制剂的质量控制方法；该制剂中氯霉素、醋酸地塞米松性质均不稳定，其含量随温度、时间递增而逐渐降解，需低温贮存，有效期仅为20d。

Aim To establish a method for determination of chloramphenicol and dexamethasone sodium phosphate in chloramphenicol dexamethasone ointment and inspect its stability. Methods HPLC is used , the mobile phase is methanol-water（ 70： 30）, the detecting wavelength is at 240nm ,the flow rate is 0.7 ml ·min^-1. These methods are to determine the content of chloramphenicol dexamethasone. Meanwhile classical constant temperature method is used to inspect the content change of chloromycetin and dexamethasone. Results Chlommycetin and the acetic acid dexamethasone have good linearity in the range of 50.01～ 300.06 mg ·L^-1 1.25 -7.50 mg· L^- 1, respectively. The mean recovery is（97.12± 3.70 ）%, （95.40 ± 3.69 ）%. The chloromycetin and the acetic dexamethasone degradation follow the first level of dynamic reaction. When the temperation was at 10℃, T0.9 is 69,19 d respectively. Conclusion The method is convenient, fast, accurate and can be used in quality control for this medicine. In this preparation the nature of chloromycetin and acetic acid dexamethasone was unstable and its content decreases along with the increase of the temperature and the time, It needs low tempera- ture storage and the validity was only 20d.