ELECTROCHEMICAL REDUCTION AT A MERCURY-ELECTRODE AND DIFFERENTIAL-PULSE POLAROGRAPHIC-DETERMINATION OF DIBUCAINE IN PHARMACEUTICAL OINTMENTS

The polarographic behaviour of dibucaine was studied using various ele ctrochemical techniques, In acidic media, a non-reversible diffusion-c ontrolled reduction process involving two electrons takes place, The l inear relationship between peak current intensity and dibucaine concen tration 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 deter minations at the 10(-5) mol l(-1) level), A simple extraction procedur e was employed for the determination of the drug in pharmaceutical for mulations and the validity of the method was confirmed by parallel det erminations using the official method of the US Pharmacopeia (HPLC).