A New Stability-Indicating and Validated RP Estimation of Tolvaptan in Bulk and Pharmaceutical RP-HPLC Method for the Dosage Forms

A stability-indicating RP-HPLC method was developed and validated for the estimation of Tolvaptan in bulk and pharmaceutical dosage forms. An Hypersil BDS C18 (100 mm x 4.6 mm I.D., 5 μm particle size) column was used as stationary phase with mobile phase consisting of 0.02M phosphate buffer having pH 3.1 adjusted with orthophosphoric acid and acetonitrile in the ratio of 35:65 V/V. The flow rate was maintained at 1 ml/min and effluents were monitored at 254 nm. The retention time was 3.460 minutes. The stress studies were performed as per ICH guidelines under acidic, alkali, oxidative, thermal, photostability and neutral conditions. The drug peak was well resolved from the peaks of degraded products. From the degradation studies it is evident that the drug showed instability under acidic, alkali, oxidative, thermal, photostability and neutral conditions. The linearity of the method was observed in the concentration range of 30–180 μg/ml with the number of theoretical plates & tailing factor being 4820 & 1.23 respectively with a correlation coefficient of 0.999. The percentage assay of Tolvaptan was found to be 99.83%. The method was validated for its accuracy, precision and system suitability. The results obtained in the study were within the limits of ICH guidelines and hence this method can be used for the estimation of Tolvaptan in pharmaceutical dosage forms.