Spectrophotometric determination of molsidomine in pharmaceutical formulations using bromocresol green

Abstract

Molsidomine (N-ethoxycarbonyl-3-morpho- linosyndonimine, SIN-10) is a syndnonimine derivative with a mesoionic structure, which possesses a sustained coronary vasodilatation and antihypertensive effect following oral administration [1]. Monitoring of molsidomine and its metabolites in biological fluids has been carried out mostly by HPLC [2, 3]. UV spectrophotometric methods [4, 5] have been used for the determination of bulk molsid- omine. No colorimetric procedure for the determination of molsidomine in the pure state or in dosage forms has been reported. The present paper describes a simple and reproducible colorimetric assay for the deter- mination of molsidomine in dosage forms. The method is based on the formation of a coloured ion-pair complex of the drug with a bromo- cresol green (BCG) as a reagent.