Extraction and electrochemical quantification of the active ingredient (diazepam) in pharmaceutical products.

A method for the extraction and separation of the active ingredient diazepam (7-chloro-di-hydro-1-methyl-5-phenyl-2H, -1,4-benzodiazepam-2-one) in pharmaceutical tablets is discussed. This method avoids the hydrolysis of diazepam. Polarographic studies with direct current (DCP), alternating current (ACP) and differential pulse polarography (DPP) were used under different sets of conditions. The pH value most suitable for these studies was found to be 4.6. The detection range for ACP was found to be from 17.4 to 167 muM, whereas for DPP, the range was 4.8-96 muM. Commercial tablets of diazepam labelled to contain 10 mg per tablet were assayed. For five replicate samples, the relative standard deviations were lower than 1% and the contents were determined with errors lower than 4%.