Abstract

A stability-indicating UV/Vis spectrophotometric method was developed and validated for estimation of diazepam in tablet dosage form. The proposed method utilized a Specord 250 plus PC double beam spectrophotometer using 1.0 cm quartz cells and all determinations were made at a wavelength of 231 nm in 1:1 methanol:distilled water. Experiments were designed for determining linearity, limit of detection and quantitation, accuracy, precision and specificity of this analytical method as per the International Organization for Standardization guidelines. The drug substance and the drug product were exposed to thermal, photolytic, hydrolytic, and oxidative stress conditions, and the stressed samples were analyzed using the proposed method to demonstrate the specificity of the method. The proposed method was found to be linear in the concentration ranges from 3.096-15.480 µg/ml with the linear correlation coefficient of R²= 0.999 and the mean recoveries were 98.36 to 100.72 %. Although the degradation products of stressed condition had not been identified, the method had been able to detect the changes due to stress condition. The stated method can be used as stability indicating method with high degree of linearity, accuracy and precision for assay of diazepam in routine pharmaceutical analysis of tablets.