Development and Validation of a Stability-Indicating Ion-Pair RP-HPLC Method for Determination of Bethanechol with UV Detection: Application to Pharmaceutical Analysis

A rapid and stability indicating ion-pair RP-HPLC method was developed for estimation of bethanechol chloride (BC) in pharmaceutical preparations. The separation was achieved on a phenyl column using a mobile phase consisting of 0.05 M phosphate buffer (pH 6) – ethanol (98:2 v/v) mixture containing 0.56 mg/mL of sodium 1-heptanesulfonate. Quantitation was achieved with UV detection at 190 nm. In forced degradation studies, the drug was subjected to oxidation, hydrolysis, photolysis, and heat. The method was validated for specificity, selectivity, linearity, precision, accuracy, and robustness. The analytical procedure was found to be linear in a BC concentration range of 5.0 – 500.0 μg/mL (r2 = 0.9997). Precision was evaluated by replicate analysis in which%deviations from relative standard values of peak areas were found below 2.0. The recoveries obtained (99.0 – 102.0%) ensure the accuracy of the proposed method. Impurities as well as excipients were well resolved from the parent drug. Accordingly, the proposed validated procedure was proved to be suitable for routine and stability analysis of BC in pharmaceutical preparations.