Determination of Lisinopril in Pure and Tablet form by Using 2-Hydroxynaphthaldehyde as Derivatizing Reagent

An easy, sensitive and accurate spectrophotometric method has been developed for the determination of Lisinopril (LNP) in pure and tablet formulations based on derivatization reaction with 2-hydroxynaphthaldehyde (2HNA). The derivatization reaction was carried out in methanol solvent at pH-5.5 at 95±2C for 15 min. The linear calibration curve was obtained that obeyed the Beer’s law within the concentration range 5-50 μgmL-1 of LNP at 433 nm with a coefficient of determination R²=0.996. The recovery was in the range from 98.25-101.82 with molar absorptivity of drug 9×103 mole-1cm-1. The method was accurate and precise (intra-day variation 0.05-0.97% and inter-day 0.07-1.6%), with limit of detection (LOD) and limit of quantification (LOQ) 0.264 μgmL-1 and 0.8 μgmL-1, respectively. No interferences from the excipients were detected. The method was applied for the rapid analysis of LNP in pharmaceutical products.