差示分光光度法测定制剂中硝苯啶的含量

利用硝苯啶溶液对光不稳定的性质,在波长350nm处测其光照前后的吸收度差值(△A),△A与硝苯啶乙醇溶液浓度在10～60μg/ml范围内呈线性关系。使用本法对硝苯啶片进行了含量测定,并对其类似物进行了干扰试验,排除了组分的干扰。该法的精密度日内为1.3%,日间为1.9%,平均回收率为99.96%。方法简便、快速,不需色谱等分离手段即可达到分析目的,专一性、重复性均较好,是分析硝苯啶制剂的一种新途径。

DETERMINATION OF NIFEDIPINE BY DIFFERENTIAL SPECTROPHOTOMETRY

This paper reports a new method for determining nifedipine based on the unstable character of nifedipine to light. The absorbance was measured at 350 nm before and after light irradiation. In this method, the contents of nifedipine in tablets were determined by differential absorbance (delta A) and the assay of nifedipine was not affected by other components. Calibration graph was linear in the range of 10-60 micrograms/ml for delta A. The precision of the method was: 1.3% within-day and 1.9% between-days. The average recovery for nifedipine was 99.69%. The method is not only better in specificity and repeatability but also simple and rapid, it would be a new way of assay for nifedipine.