Development and Validation of a Simple, Stability-Indicating High-Performance Liquid Chromatographic Method for Analysis of Tolterodine Tartrate in the Bulk Drug and in its Tablet Formulation

A stability-indicating HPLC method has been developed for analysis of tolterodine tartrate in the bulk drug and in formulations. Acceptable separation of the drug and its degradation products was achieved at 40 degrees C on a 4.6 mm i.d. x 250 mm, 5-mu m particle, C(18) column with 40:60 (v/v) buffer solution-methanol containing 0.5% (v/v) triethylamine as mobile phase. The pH of the mobile phase was adjusted to 7.0 +/- 0.1 with orthophosphoric acid. The flow rate was 1.2 mL min(-1) and the detection wavelength 220 nm. The method was validated for linearity, precision, accuracy, specificity, and robustness. Response was a linear function of concentration over the range 1-100 mu g mL(-1). The slope of the calibration plot was 17.82 mV s(-1) ppm(-1), the correlation coefficient 0.999, and the relative standard deviation (RSD) 0.23%. Assessment of precision revealed method RSD was low - from 1.59 to 1.88% for intra-day precision and from 0.59 to 1.90% for inter-day precision. Stress degradation studies showed tolterodine tartrate was stable to acidic and neutral hydrolysis, oxidative stress, photolytic stress, and thermal stress but labile to alkaline hydrolysis.