Square-wave adsorptive cathodic stripping voltammetry was used to determine pioglitazone HCl in Britton Robinson buffer of pH5. The adsorptive cathodic peak was observed at -1.5 V vs. Ag/AgCl. The peak response was characterized with respect to pH, supporting electrolyte, frequency, scan increment, pulse-amplitude, accumulation potential and pre-concentration time. Under optimal conditions, the peak current is proportional to the concentration of pioglitazone HCl, and a linear calibration graphs were obtained within the concentration levels of 10(-8) and 10(-4) M following different accumulation time periods (0-300 s). The obtained results were analyzed and the statistical parameters were calculated. The detection limit is 8.08 × 10(-9) M (3.17 ng ml(-1)) using 300 s pre-concentration time, whereas the quantitative limit is 2.45 × 10(-8) M (9.63 ng ml(-1)). The proposed method was applied to assay the drug in pharmaceutical formulations and biological fluids. The pharmacokinetic parameters of drug in human plasma were estimated as: C max=785.8 ng ml(-1), t max=1.5 h, K e=0.125 h(-1) and t 1/2=8 h which are favorably compared with those reported in literature.
Keywords: actos tablets; adsorptive stripping voltammetry; biological fluids; pharmacokinetic; pioglitazone HCl; square-wave.