Electrochemical reduction at a mercury electrode and differential-pulse polarographic determination of dibucaine in pharmaceutical ointments

Abstract

The polarographic behaviour of dibucaine was studied using various electrochemical techniques. In acidic media, a non-reversible diffusion-controlled reduction process involving two electrons takes place. The linear relationship between peak current intensity and dibucaine concentration allowed the differential-pulse polarographic determination of dibucaine over a wide concentration range, from 10^–6 to 10^–4 mol l^–1 at pH 2.6, with a relative standard deviation of 1.9%(nine determinations at the 10^–5 mol l^–1 level). A simple extraction procedure was employed for the determination of the drug in pharmaceutical formulations and the validity of the method was confirmed by parallel determinations using the official method of the US Pharmacopeia (HPLC).