Design and validation of a robust stability-indicating reversed-phase HPLC method for quantification of mesalamine in formulated drug products

A reliable and sensitive RP-HPLC method was developed and validated for the accurate quantification of mesalamine in bulk and formulated pharmaceutical products. The analysis was carried out on a C18 column (150 mm × 4.6 mm, 5 μm) using a mobile phase of methanol: water (60:40 v/v), with a flow rate of 0.8 mL/min, and UV detection at 230 nm. Methanol: water (50:50 v/v) was used as the diluent. The method demonstrated excellent linearity across the concentration range of 10-50 µg/mL (y = 173.53x - 2435.64, R² = 0.9992), high accuracy with recoveries between 99.05% and 99.25% (%RSD < 0.32%), and outstanding precision with intra- and inter-day %RSD values below 1%. Robustness was confirmed under slight method variations (%RSD < 2%), and LOD and LOQ were found to be 0.22 µg/mL and 0.68 µg/mL, respectively. Forced degradation studies under acidic, basic, oxidative, thermal, and photolytic stress confirmed the method's specificity and stability-indicating capability. Assay of a commercial mesalamine tablet (Mesacol^®, 800 mg label claim) showed a recovery of 99.91%, validating the method's applicability for routine quality control and regulatory compliance.