Electrochemical determination of some antidiabetic drugs for type 2 diabetic patients

Quantitative determination of rosiglitazone, pioglitazone, glimepiride and glyburide as antidiabetic drugs for type 2 diabetic patients was performed conveniently and economically using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Carbon paste (CPE) and glassy carbon (GCE) electrodes were successfully used as sensors for these drugs in Briton-Robinson (B-R) as buffer solution. The preparation of CPE and the GCE as ion selective electrodes is based on the construction of 10% standard drug ion pair with reineckate or tungstophosphate imbedded as electroactive material. Working standards were freshly prepared just before the assay by dilution from a 10(-2)mol L(-1) drug stock solution. At a scan rate of 100 mV s(-1) the cyclic voltammograms showed a well defined anodic peak with high selectivity. The DVP gave a reproducible well defined diffusion controlled peak for each drug at a scan rate of 10 mV s(-1). The oxidation peaks were used to determine the tested drug concentrations. The quantitative determination of the four drugs in their pharmaceutical preparations by the proposed electrochemical technique was found to be identical with the values obtained by the standard HPLC method. A mean % recovery of 100+/-1 was obtained and the % relative standard deviation was 1.62 indicating the high precision of the method and the confidence in its repeatability. The proposed electroanalytical technique using either the CPE or the GCE is economic, selective and can be applied for both the qualitative and quantitative determination of the drugs in their pharmaceutical preparations, without special drug separation.