Quantitative Analysis of Acetaminophen, Ethoxybenzamide, Piroxicam, Hydrochlorothiazide, Caffeine, Chlorzoxazone and Nicotinamide Illegally Adulterated in Chinese Medicinal Pills

MU-CHANG TSENG, MINE-JER TSAI AND KUO-CHING WEN

National Laboratories of Foods and Drugs, Department of Health, Executive Yuan

   A traditional Chinese medicine, which was supplied as pills by a temple and used as Ch'i tonic, was obtained for testing the illegal adulteration with chemical drugs. In the qualitative analysis, two-dimensional TLC, with chloroform:ethanol(9:1,v/v) and ethyl acetate: methanol: ammonia water(8:1:1,v/v) as the solvent systems, established the presence of acetaminophen, piroxicam, hydrochlorothiazide, caffeine, ethoxybenzamide, chlorzoxazone and nicotinamide in the pills. In quantitative analysis, a reversed-phase HPLC method has been established for simultaneous determination of the seven chemical drugs. The analysis of the sample extract was performed on a Cosmosil 5C18-AR column (4.6 × 150mm) by a linear gradient elution with 1%triethylamine - 1% phosphoric acid buffer, acetonitrile and methanol(0 min, 90:5:5; 60min, 40:30:30; 70min,90:5:5) as the mobile phase at 1ml/min and with fenbufen as an internal standard. The monitor was set at 260nm. System suitability tests showed that the established method was quite suitable for the determination of the adulterants in pills. By using this method, 78mg of acetaminophen, 16mg of piroxicam, 30mg of caffeine, 30mg of ethoxybenzamide, 41mg of chlorzoxazone, 4mg of hydrochlorothiazide and 16mg of nicotinamide, were found in each pill of the sample.

Key words: Traditional Chinese medicine, HPLC, TLC, acetaminophen, piroxicam, ethoxybenzamide, chlorzoxazone, caffeine, hydrochlorothiazide, nicotinamide