Micellar Electrokinetic Capillary Chromatography of Clobenzorex HCl and Diazepam Adulterated in Anorexiant Traditional Chinese Medicine

A method employing micellar electrokinetic capillary chromatography was developed for the assay of clobenzorex hydrochloride and diazepam adulterants in traditional Chinese medicine. A buffer solution containing 25 mM sodium tetraborate, 25 mM sodium dodecyl sulfate and 10 % acetonitrile solution was used. The linear calibration ranges were 100-250µg/mL (r = 0.9997) for clobenzorex hydrochloride and 5-40µg/mL (r = 0.9990) for diazepam with recoveries of 92.1-103.1 % and 84.8-102.6 %, respectively. The relative standard deviations for intraday and interday analyses were 0.18-0.88 % and 1.25-2.88 % for clobenzorex hydrochloride and 1.24-2.28 % and 0.42-2.29 % for diazepam. The content of clobenzorex hydrochloride and diazepam in powdered forms of traditional Chinese medicine ranged from 11.1 to 35.4 mg/pack and 1.5-2.7 mg/pack, respectively. The capsule forms of the medicine were found to contain from 3.1 to 9.7 mg/cap clobenzorex hydrochloride and 0.4 to 0.6 mg/cap diazepam.