Polarographic assay of nitrazepam formulations

Abstract

A simple, rapid, d.c. polarographic method has been developed for the determination of nitrazepam in its pharmaceutical formulations. Ethanol was employed as the solvent for extracting the drug from the formulations and five different buffer systems, namely hydrochloride (pH 1.0–2.2), Mcllvaine (pH 2.2–8.0), acetate (pH 3.6–5.6), borate (pH 7.8–10.0) and Britton-Robinson (pH 2.0–12.0), were used individually as the supporting electrolyte. Nitrazepam is reduced in two-step, irreversible, diffusion-controlled and pH-dependent waves. Results obtained by the proposed method are in excellent agreement with those given in the British Pharmacopoeia. Commonly used tablet excipients were found not to interfere. A comparison was also made with different batches of nitrazepam tablets and capsules by the proposed method.