Enhanced selectivity approach for fast analysis of enalaprilat, lisinopril and benazepril in pharmaceutical dosage forms and spiked human plasma by ion chromatography

Abstract

A simple and highly selective method for determination of enalaprilat (ENT), lisinopril (LSP) and benazepril hydrochloride (BZP) in pharmaceutical dosage forms as well as spiked human plasma by ion chromatography with UV detection has been developed. ENT and LSP are compounds with little inherent hydrophobicity that make their analysis using HPLC essentially sophisticated necessitating either complex extraction procedures or especial detection methods. The method proposed is based upon ionization of those two drugs in basic medium to be well retained and readily resolved as dicarboxylic acid anions using IonPac AS11 (13 μm particle size, 4 × 250 mm, Dionex) anion exchange column adopting a very simple clean-up procedure via a single-step protein precipitation with UV detection at 215 nm. The three drugs were successfully determined in pharmaceutical dosage forms as well as in spiked human plasma with tyrosine as internal standard with a recovery approaching 100%. Adopting this proposed procedure, the analytes produce well shaped peaks with good linear relationship over the investigated concentration ranges and values of (r) higher than 0.998 for all drugs. ion level of200 ng ml-1 of the three drugs, therefore being satisfactory for their purposed analysis. The method was validated with respect to specificity, recovery, accuracy, precision and linearity. Moreover, the method could be applied to the determination of the drugs in pharmaceutical preparations. The method was validated with respect to specificity, recovery, accuracy, precision and linearity and the method proved applicable for routine fast analysis of the studied drugs.