Development and Validation of a Reverse Phase High-Performance Liquid Chromatographic Method for Quantitative Estimation of Methenamine Hippurate in Tablet Dosage Form

Abstract

Methenamine Hippurate (MEH) is a urinary antiseptic widely prescribed for the prophylaxis and treatment of recurrent urinary tract infections. The drug acts by releasing formaldehyde in acidic urine, thereby exerting antibacterial activity against a broad spectrum of urinary pathogens. Reliable analytical methods are essential to ensure the quality, safety, and efficacy of pharmaceutical formulations containing Methenamine Hippurate. Although several analytical techniques including spectrophotometry, fluorimetry, gas chromatography, and LC-MS methods have been reported, only limited RP-HPLC methods are available for routine quantitative estimation of Methenamine Hippurate in tablet dosage forms. The present study aimed to develop and validate a simple, rapid, accurate, precise, and economical reverse-phase high-performance liquid chromatographic (RP-HPLC) method for quantitative estimation of Methenamine Hippurate in tablet dosage formulations. Chromatographic separation was achieved using a Phenomenex Kintex C18 column (4.6 × 150 mm, 5 μm) with a mobile phase consisting of water containing 0.1% orthophosphoric acid and methanol (70:30, v/v) under isocratic conditions. The flow rate was maintained at 1.0 mL/min and detection was performed at 230 nm using a PDA detector. The developed method was validated according to ICH Q2(R1) guidelines for system suitability, linearity, accuracy, precision, ruggedness, robustness, and specificity. Methenamine Hippurate exhibited a sharp and symmetrical chromatographic peak with a retention time of approximately 3.83 min. The developed method demonstrated excellent linearity over the concentration range of 500–1500 µg/mL with a correlation coefficient (R²) of 0.999. Accuracy studies showed recovery values ranging from 99.70% to 99.87%. Precision and ruggedness studies yielded %RSD values below 2%. The assay of the marketed tablet formulation showed drug content of 99.70% of the labeled claim. Robustness studies confirmed the reliability of the method under deliberate variations of chromatographic conditions. The developed RP-HPLC method was found to be simple, accurate, precise, robust, and economical. The method is suitable for routine quality control analysis, dissolution studies, and stability testing of Methenamine Hippurate tablet formulations.