Simultaneous determination of the active ingredients in composite pseudoephedrine hydrochloride tablets by capillary electrophoresis

A simple, rapid and specific capillary electrophoresis (CE) method has been developed for the separation and determination of pseudoephedrine hydrochl oride (PSED), paracetamol (PRCT) and dextromethorphan hydrochloride (DEMP) with UV detection. The CE was performed in 20 mmol/l sodium phosphate buffe r solution (pH 7.0). The three ingredients were completely separated within 5 min, and quantified with an UV-detector at 200 nm. Relative standard dev iations of 0.85% for PSED, 3.90% for PRCT and 0.84% for DEMP were achieved for seven injections of the sample containing about PSED of 30 mug/ml, PRCT of 325 mug/ml and DEMP of 15 mug/ml. The excellent linearity was obtained in the concentration range 300.0-2.5 mug/ml for PSED, 500.0-5.0 mug/m for P RCT and 500.0-10.0 mug/m for DEMP. The detection limits for PSED, PRCT and DEMP were 0.75, 1.20 and 2.50 mug/ml, respectively. The proposed method has been applied to the monitoring of commercial composite pseudoethedrine tab lets and biological sample (urine). The analytical results were satisfactor y. (C) 2000 Elsevier Science B.V. All rights reserved.