Differential Pulse Polarographic Study of Amoxicillin and Ciprofloxacin and its Determination in Pharmaceuticals

A differential pulse Polarographic method have been developed and validated for the direct determination of amoxicillin and ciprofloxacin in pharmaceuticals. The results show that the optimal analysis conditions for amoxicillin and ciprofloxacin was; the water as a best solvent at neutral medium, pH 7 , while for ciprofloxacin was at acidic medium, pH 4, with BritonRobinson buffer solution and 3M KCl as a supporting electrolyte also 4mm3 mercury drop size at 25°C. Amoxicillin showed two peaks, the first one at - 0.25V and the other one at -0.83V, while the ciprofloxacin appears one peak at the applied potential -1.41V. A standard calibration plot of amoxicillin and ciprofloxacin was prepared in the range between 0.05- 0.525µg.ml-1. The accuracy and precision of the method for the determination of both analyte was tested. The results of laboratory amoxicillin samples showed the SD was 0.08 and RSD% did not exceed 0.13%, while the results of laboratory ciprofloxacin samples illustrate the SD was 0.26 and the RSD% did not exceed 0.4%. The actual value of the peak potential Ep and the number of electrons required for the reduction for amoxicillin and ciprofloxacin was calculated using Ilkovic -Heyrovsky equation, the results confirm the first peak potential Ep was -0.832V with 2 electron used and the second Ep was -0.249V with 1 electron used, while the value of the ciprofloxacin peak potential Ep was -1.38 V with 2 electrons required. This method effectively applied in commercial amoxicillin and ciprofloxacin pharmaceuticals.