Spectrophotometric and titrimetric methods for the determination of nordiazepam in pure and pharmaceutical dosage form

A spectrophotometric method and two titrimetric methods for the determination of nordiazepam via its iodobismuthate complex are described. These methods depend on the reaction of nordiazepam with potassium bismuth iodide which give an orange precipitate. Determination of nordiazepam in the precipitated complex is done iodometrically using standard potassium iodate solution or complexometrically using standard EDTA solution and xylenol orange indicator. Alternatively, the complex is dissolved in ethanol and its absorbance is measured at 323 nm. The three methods were applied for the determination of reference samples of nordiazepam in the concentration range of 1–30 mg ml−1 (for the iodometric method) and of 5–30 mg ml−1(for the complexometric method) and of 0.04–3.2 mg ml−1 (for the spectrophotometric method). The proposed methods were applied for the determination of nordiazepam in madar tablets and the validity of the proposed methods was assessed by applying the standard addition technique.