A new HPLC method was developed for selective and simultaneous determination of Temazepam. The developed method is also applicable for the related substances determination in Temazepam. The chromatographic separation was achieved on a Zorbax SB C-18, 4.6 x 250mm, and 5μ column. The mobile phase consisted of buffer and acetonitrile (60:40, V/V) delivered at a flow rate of 2.0 mL min−1. Buffer consisted of 0.03M of dipotassium hydrogen orthophosphate and 2 mL of triethylamine, adjusted to a pH 3.0 with ortho phosphoric acid. The mobile phase was pumped at a flow rate of 2.0 mL min−1 and UV detector at 245 nm was used. In the developed HPLC method, the resolution between Temazepam and its potential impurities, namely Impurity-A, Impurity-B, Impurity-C, and Impurity-G was found to be satisfactory. Accuracy, found by recovery experiments varied between from 99.2-100.5 at 80.0% to 120.0% level. The curves between concentration is response were linear with coefficient of corrolation (r) not less than 0.99. The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. Considerable degradation was found to occur in acid hydrolysis condition. The stress samples were assayed against a qualified reference standard and the mass balance was found close to 95% - 105%. The developed Reverse Phase-LC method was validated with respect to specificity, linearity, accuracy, precision and robustness. The validation was performed according to the current requirements as laid down in the ICH guidelines.
