A validated stability-indicating HPLC related substances method for rivastigmine tartrate in bulk drug and dosage form

A gradient reverse phase high performance liquid chromatography (RP-HPLC) was developed for the quantitative determination of Rivastigmine tartrate in bulk drugs and in pharmaceutical dosage form. The developed method is stability indicating which separates the drug from degradation products and is also applicable for related substance determination of Rivastigmine tartrate in bulk drug. The chromatographic separation was achieved on a Inertsil sprint C8 column (250 x 4.6mm, 5μ) and the mobile phase containing the mixture of solution-A [acetonitrile and 0.1% of orthophosphoric acid in water (15:85v/v, pH3.2 adjusted by Triethylamine)] and solution-B [acetonitrile and 0.1% of orthophosphoric acid in water (85:15v/v, pH3.2 adjusted by Triethylamine)]. The flow rate of the mobile phase is set at 1.0mL/min. The detection was carried out at wave length 220nm and column oven temperature at 30°C. The chromatographic resolution between its impurities and degraded products was found to be greater than three. Forced degradation studies were performed for Rivastigmine tartrate bulk drug using Acid (4N HCl) Base (3N NaOH), Oxidation (4% H2O2) and 80oC heat. The degradation was observed for Rivastigmine tartrate in Acid, Base and Oxidation. The mass balance of Rivastigmine was close to 100% in all the stress conditions. The developed method was validated with respective linearity, accuracy, precision, roubustness and forced degradation studies prove stability indicating power of the developed method.