Flow Injection- Spectrophotometric Determination of Clonazepam Based On Its Oxidative Condensation with Promethazine Hydrochloride

Abstract

Simple methods were proposed for the spectrophotometric determination of clonazepam (CLO) in pharmaceutical formulations. The methods were based on the reaction of CLO with promethazine hydrochloride (PMH) in the presence of potassium periodate. The green water soluble product was measured at λmax 606 nm using both batch and flow injection analysis (FIA) approach. The effect of chemical and physical parameters was investigated by univariate method. Under the optimum conditions, calibration graphs were observed linear from 0.5-25 and 5-120 μg mL-1 CLO with detection limits of 0.23 and 1.38μg mL-1 CLO by batch and FIA procedure respectively. The relative standard deviations of the proposed methods were less than 1.03 and 1.64 by batch and FIA procedure respectively. The FIA sample throughput was 120 sample per hour. The proposed methods were successfully applied to the determination of CLO in its pharmaceutical preparations