Determination of secnidazol in pharmaceutical tablets and intestinal fluids by differential pulse polarography

A differential pulse polarography (DPP) method has been developed for quantitative determination of secnidazol in pharmaceutical tablets and intestinal fluids in a 0.04 M borate buffer. The reduction wave obtained showed that four electrons are involved in the process due to the reduction of the nitro group to hydroxilamine. In the lower pH range the protonated form of the hydroxilamino group is reduced to an amine group. The limiting current remains constant in a pH range of 3.5–5.8. In alkaline solutions the limiting current is significantly higher than a four electron reduction and limits to a six electron reduction, because it involves base catalysed dehydration of the hydroxilamino derivative formed in the first step yielding a ketimine, which is reduced in this conditions. The half-wave potentials are linearly shifted to more negative potentials with the increase of pH. The system is irreversible and controlled by diffusion. The determination of secnidazol in pharmaceutical preparations (Secnidal® and intestinal fluids) were carried out employing DPP and compared with HPLC technique.