Determination of Entacapone in Pharmaceutical Preparations by Liquid Chromatography

A reverse phase high performance liquid chromatographic method (HPLC) has been developed for the estimation of entacapone in its dosage forms using C₁₈ column. The mobile phase (acetonitrile and 20 mM potassium dihydrogen phosphate, P^H 3.5) was pumped at a flow rate of 1 ml/min in the ratio of 80:20 and the eluents were monitored at 320 nm. The intra- and inter- day variation was found to be less than 2% showing high precision of the assay method. The mean recovery of the drug from the solution containing 200 or 300 μg/ml was 99.66±1.20% indicating high accuracy. The proposed HPLC method may be used for determining entacapone in bulk drug samples or in pharmaceutical dosage forms.