Direct Spectrophotometric Determination of Perindopril Erbumine and Enalapril Maleate in Pure and Pharmaceutical Dosage Forms using Bromocresol Green

Abstract

In this article, it has been reported new, simple, sensitive and direct spectrophotometric methods for the determination of Perindopril Erbumine (PPE) and Enalapril Maleate (ENL) in pure and in pharmaceutical forms. Spectrophotometric methods are based on the formation of yellow colored ion-pair complexes between PPE, ENL and sulphonphthalein acid dye, Bromocresol green (BCG) into chloroform were measured at the wavelength of 414 and 415nm for PPE and ENL, respectively. The optimal analytical conditions were determined. The obtained complexes (BCG: PPE) and (BCG: ENL) reached maximum absorbance directly after formation at room temperature for a stability period of 24 h. Beer’s law were obeyed in the concentration ranges of (2-20)µg/mL for PPE and (8- 44)µg/mL for ENL, the limit of detection of 0.125μg/mL and 0.230μg/mL were found for PPE and ENL, respectively. The molar absorptivity coefficients were 4.4045*104 L.moL-1.cm-1 for PPE and 1,9330*104 L.moL-1.cm-1 for ENL. The stoichiometry of the complexes formed between PPE, ENL and BCG were 1:1. No interference was observed from common excipients occurred in pharmaceutical formulations and the proposed methods have been successfully applied to determine the PPE and ENL in some pharmaceutical products and in ENL combination dosage forms with hydrochlorothiazide (HCTZ). The proposed methods were successfully validated to be utilized in the quantitative analysis of PPE and ENL in their pure and pharmaceutical products. A good agreement between the developed spectrophotometric methods with the results obtained from official reference methods for the determination of the two drugs in some real samples demonstrate that the proposed methods were suitable to quantify PPE and ENL in pharmaceutical formulations.