Detection of phenobarbital and seven other sedative hypnotics illegally adulterated into traditional Chinese medicines and health foods by HPLC-DAD / 中国药学杂志

ABSTRACT

OBJECTIVE: To establish an HPLC-DAD method for the detection of midazolam, phenobarbital, estazolam, oxazepam, nitrazepam, alprazolam, clonazepam and diazepam illegally adulterated into traditional Chinese medicines and health foods. METHODS: An Alltima C18 column (4.6 mm × 250 mm, 5 μm) was used for the separation with 10 mmol · L-1 ammonium dihydro-gen phosphate (adjusted pH to 2.7 with H3PO4) - acetonitrile (65:35) or 10 mmol · L-1 ammonium dihydrogen phosphate (adjusted pH to 2.7 with H3PO4) - methanol (40:60) as the mobile phase at the flow rate of 0.5 mL · min-1. The detection wavelength was 220 nm. RESULTS: The method showed good linearity and sensitivity for the 8 compounds with all correlation coefficients (r) greater than 0.9997 and all LODs between 4.3 - 13.0 ng · mL-1; the spiked recoveries of low, middle and high levels ranged from 98.08% to 102.1%; the precisions were satisfactory with all RSDs lower than 1.58%; the stability within 12 h was acceptable with the RSDs of peak areas and retention times no more than 1.05% and 0.54%. In the test of 19 samples of different dosage forms, nitrazepam was found in two health foods. CONCLUSION: This method is fast, sensitive and propagable for the detection of 8 sedative hypnotics illegally adulterated into traditional Chinese medicines and health foods. Copyright 2012 by the Chinese Pharmaceutical Association.