Química medicinal

RP-HPLC Method for the Simultaneous Determination of Captopril and H₂-Receptor Antagonist: Application to Interaction Studies

Abstract

Najma Sultan, Safila Naveed and M Saeed Arayne

Rapid, sensitive, simple and accurate high-performance liquid chromatographic (HPLC) method is developed and validated for the simultaneous determination of captopril with H2 receptor antagonists as cimetidine, ranitidine and famotidine. Captopril was separated from H2 receptor antagonist using pre packed Purospher star C18 (5 μm, 25×0.46 cm) column methanol: water (60:40 v/v) were used as the mobile phase, pH 3.0 ± 0.02 was adjusted by orthophosphoric acid. The flow rate was 0.8 mLmin-1 at ambient temperature, diluent was 50:50 methanol water while UV detection was performed at 225 nm. The retention time for captopril was found to be 5.2 minute, for ranitidine and famotidine 2.5 minute and cimetidine 2.7 minute. Each drug showed a good resolution from captopril. In vitro interaction studies of captopril with commonly administered H2 receptor antagonists i.e. cimetidine, ranitidine and famotidine were carried out at 37°C using above validated method. These studies clearly indicated that H2-receptor antagonists bind to captopril causing drastic changes in the availability of the drug.