DEVELOPMENT AND VALIDATION OF HPLC AND SPECTROSCOPIC METHOD OF ESTIMATION OF ANTIHYPERTENSIVE DRUG

The aim of this research was to develop and validate a stability-indicating Reverse Phase High Performance Liquid Chromatography (RP-HPLC) method for the simultaneous estimation of Lisinopril and Atenolol in pharmaceutical topical dosage forms. The method was designed to be robust, precise, and capable of distinguishing the active pharmaceutical ingredients (APIs) from their degradation products under various stress conditions. Chromatographic separation was achieved using a C18 column (250 mm × 4.6 mm, 5 μm particle size) with a mobile phase consisting of Acetonitrile: Phosphate Buffer (pH 3.00) (60:40). The flow rate was maintained at 1.0 mL/min, and detection was carried out at 231 nm using a UV detector. The retention time of drug was found to be 5.241 and 7.724 for LSP and ANL respectively. The method was validated according to ICH guidelines for linearity, accuracy, precision, specificity, limit of detection (LOD), limit of quantification (LOQ), and robustness. Linearity was observed in the concentration range of 25-150 μg/mL for Lisinopril and 10-60 μg/mL for Atenolol, with correlation coefficients (r²) of 0.998 and 0.999 respectively. The method demonstrated good accuracy, with recovery rates between 98.0% and 102.0% for both drugs. Precision, both intra-day and inter-day, showed relative standard deviation (RSD) values of less than 2%. The developed RP-HPLC method is reliable, efficient, and suitable for the simultaneous estimation of Lisinopril and Atenolol in pharmaceutical oral dosage forms. It can be successfully applied for routine quality control and stability testing of these agents. Keywords: Lisinopril, Atenolol UV Spectrophotometry, RP-HPLC, Simultaneous Estimation, Method Validation.