Direct derivative spectrophotometric determination of nordiazepam in presence of its degradation product

The use of second order derivative spectrophotometry allows the direct determination of nordiazepam in presence of its acid induced degradation product namely, 2-amino-5- chloro benzophenone. Zero crossing technique was applied by measuring the absolute value of the second derivative curves at the zero contribution of the corresponding benzophenone degradation product. Determination of nordiazepam can be carried out directly by measurement at 318 nm in the second order derivative spectra [both in methanolic hydrochloric acid]. The limit of sensitivity is 2-14 mcg ml [-1] with an accuracy of 100.08 +/- 0.32. The procedure was applied successfully for the determination of nordiazepam in tablets with an accuracy of 99.81 +/- 0.33