The simultaneous voltammetric determination of metronidazole with omeprazole as well as tinidazole with omeprazole in model solution, human
urine samples and in a mixture of two pharmaceutical formulations or in a combined pharmaceutical formulation (HELI-CURE® Tablets) were
applied using hanging mercury droping electrode as a working electrode vs. Ag/AgCl sat'd KCl as reference electrode. The optimal conditions for
simultaneous determinations were obtained in 0.1 M phosphate buffer (pH~7) using the standard addition method without the necessity for
samples pretreatment and / or time-consuming extraction steps prior to analysis. Furthermore, the excipients present in the pharmaceutical
formulations did not cause interference with tinidazole, metronidazole or omeprazole determination. The LOD of metronidazole and omeprazole in
dual regime found to be 0.7x10-7 and 0.25x10-8 respectively. The LOD of tinidazole and omeprazole in dual regime found to be 0.45x10-7 and
0.36x10-8 respectively. The results showed that there was no significant difference between the calculated and real values of the analytes in
biological fluids and medicaments samples. The obtained results indicate, the developed method is accurate with high recoveries and it can be
recommended for routine analysis in the majority of drug quality control laboratories.