C型甲苯咪唑的红外光谱定量测定

本文用红外光谱法测定了甲苯咪唑中晶型C的含量。取高铁氰化钾细粉(6mg)为内标物,与样品细粉(30mg)在0.25ml液体石蜡中仔细研磨均匀。将糊状物放入0.1mm铅片隔开的KBr窗片之间,分别于800～850cm^-1和2050～2150cm^-1以吸收度的方式扫描谱图。最后以834和842cm^-1,2114和2140cm^-1吸收度之差按内标法计算甲苯咪唑C型晶型的百分含量。该法对甲苯咪唑原料和片剂都适用,操作简便、专属性高,结果满意。

INFRARED SPECTROMETRY DETERMINATION OF POLYMORPHIC FORM C IN MEBENDAZOLE

Mebendazole displays polymorphism. There are three polymorphic forms (A, B and C) which were identified by means of IR and X-ray diffraction techniques. Procedures have been worked out to determine the amount of the polymorphic form C in pure mebendazole and in tablets. The sample (30 mg) and internal standard (K3Fe(CN)6, 6 mg) were mulled in 0.25 ml of mineral oil and placed between KBr plates separated by a 0.1 mm lead spacer. The spectra were recorded by the absorbance mode between 850-800 cm-1 and 2150-2050 cm-1. Both of the base lines are the horizontal line from 2140 cm-1 peak valley and from 842 cm-1 peak valley. The values of the absorbance difference were measured at 834 and 842 cm-1, 2114 and 2140 cm-1 respectively. The percent content of the polymorphic form C was calculated by the method of internal standard. This analytical approach is simple and the results are satisfactory.