DEVELOPMENT AND VALIDATION OF ANALYTICAL METHODS FOR THE SIMULTANEOUS DETERMINATION OF ENALAPRIL MALEATE, HYDROCHLOROTHIAZIDE AND PARACETAMOL IN BULK DRUGS AND PHARMACEUTICAL TABLETS USING UV SPECTROPHOTOMETRY AND RP-HPLC

Dr. Prashanthi Evangelin, D. Simhadri*, K. Vidya Sagar,  A. Suresh Kumar Reddy

The objective of the present investigation was to establish and validate a convenient, sensitive, precise, and reproducible RP-HPLC procedure for the simultaneous determination of Enalapril Maleate, Hydrochlorothiazide, and Paracetamol in bulk materials and pharmaceutical tablet preparations. Chromatographic conditions were systematically optimized by evaluating the column, mobile-phase composition, flow rate, detection wavelength, and column temperature. The optimized separation was achieved using a Thermo Hypersil-BDS C8 column (250 × 4.6 mm, 5 µm) with a 75:25 (v/v) mixture of phosphate buffer, prepared from potassium dihydrogen phosphate and dipotassium hydrogen phosphate, and acetonitrile as the mobile phase. An isocratic elution mode was employed at a flow rate of 1.0 mL/min, with detection performed at 210 nm and the column maintained at 30°C. A 20 µL injection volume was used, and the mobile phase served as the diluent. During method development, different chromatographic conditions were investigated to obtain satisfactory separation, peak symmetry, resolution, and column efficiency. The optimized procedure provided distinct and adequately resolved responses for all three analytes with suitable chromatographic characteristics. The analytical procedure was validated according to ICH recommendations by assessing parameters such as specificity, linearity, accuracy, precision, robustness, ruggedness, and system suitability. The validation results indicated that the method possesses suitable performance characteristics for simultaneous quantitative analysis of Enalapril Maleate, Hydrochlorothiazide, and Paracetamol. The applicability of the proposed method was demonstrated through the analysis of pharmaceutical tablet formulations containing the selected drug combination. The procedure requires relatively simple chromatographic conditions and provides reproducible analytical results, making it appropriate for routine quality-control testing of bulk drugs and finished pharmaceutical dosage forms. Thus, the developed RP-HPLC method provides a practical analytical approach for the simultaneous determination of Enalapril Maleate, Hydrochlorothiazide, and Paracetamol.