NOVEL POLAROGRAPHIC METHODS FOR DETERMINATION OF PIOGLITAZONE HCL IN PURE FORM AND PHARMACEUTICAL FORMULATIONS

摘要

A sensitive methods are described for the determination of pioglitazone HCl(PGZ-HCl) as anti-diabetic drug in its pure form and pharmaceutical formulations. The proposed methods depends on the polarographic activity of PGZ-HCl in Britton-Robinson buffer over the pH range2-12 using direct current (DC) and differential pulse polarography (DPP), and it showed well-defined two cathodic peaks with high selectivity. Its electrochemical behavior at a dropping mercury electrode (DME) and stating mercury drop electrode (SMDE) has been investigated. Polarograms of the drug at DME & SMDE in B–R buffer at pH 6.0 exhibited two 2-electron irreversible cathodic peaks, the first peak (Ep1) is in the range of potential at -0.05V to -0.10V,while the second peak (Ep2) is in the potential ranges at -0.975V to -1.10V versus Ag/AgCl. The first and second peaks may be attributed to the reduction of oxy group (peak1) and C=N group (peak2), respectively. The diffusion current–concentration relationship was found to be rectilinear over the range1.6–224 μg.mL-1 and 1.6–28 μg.mL-1 for Ep1and over the ranges 1.6–256 μg.mL-1 and 1.6–32 μg.mL-1 for Ep2 using DME & SMDE, respectively, with limit of quantifying PGZ-HCl was 1.6 μg.mL-1, and relative standard deviation (RSD) ±4.0% & ±4.3% for Ep1 & Ep2 using DME and ±3.6% & ±3.8% for Ep1 & Ep2 using SMDE. The peaks were characterized as being irreversible, diffusion-controlled although adsorption phenomenon played a limited role in the electrode process. The proposed methods were novel, simple, accurate and successfully applied to the determination PGZ-HCl in pharmaceuticals and the average percentage recovery was in agreement with that obtained by the official USP method