SPECTROPHOTOMETRIC DETERMINATION OF RAMIPRIL IN PURE AND PHARMACEUTICAL FORMS USING TRIPHENYL METHANE DYES

Abstract

Four new simple and sensitive extractive spectrophotometric methods have been developed and described for the determination of Ramipril in pure and pharmaceutical formulations. The developed methods involve formation of coloured chloroform extractable ion-pair complexes of Ramipril with triphenyl methane dyes viz., bromocresol green (BCG), bromophenol blue (BPB), bromothymol blue (BTB) and bromocresol purple (BCP) in acidic medium. The extracted ion-pair complexes absorb maximally at 412, 416, 415 and 407nm with use of the BCG, BPB, BTB and BCP respectively. The stoichiometry of the complex in four cases is found to be 1:1. The Beer’s law is obeyed in the concentration ranges 2.5-25µg/mL with BCG, BPB, BTB and BCP. The effect of concentration of dye, pH and interference of excipients have been studied and optimized. The limits of detection and quantification have been determined for all the four methods. These methods have been validated as per the guidelines of International Conference on Harmonization (ICH) and have been applied to the determination of Ramipril in commercial tablets and results of analysis were validated statistically through recovery studies. Thus the newly developed methods are accurate, efficient and stable.