Electrochemical Determination of the Antidiabetic Drug Repaglinide

The electrochemical oxidation of repaglinide has been carried out in Britton-Robinson buffer at carbon paste and glassy carbon electrodes. Repaglinide exhibits a well-defined irreversible oxidation peak over the entire pH range (2-11). Differential pulse voltammetry was used to determine repaglinide in pure form. The peak current varied linearly in the following ranges: 8.0 x 10(-7)-3.2 x 10(-6) M and 4.0 x 10(-7)-4.0 x 10(-6) M in case of carbon paste electrode and glassy carbon electrode, respectively. In case of carbon paste electrode the limits of detection (LOD) and quantification (LOQ) were 1.348 x 10(-7) M and 4.494 x 10(-7) M, respectively. For glassy carbon electrode the LOD and LOQ were 1.062 x 10(-7) M and 3.54 x 10(-7) M, respectively. The percentage recoveries were found in the following ranges: 99.09-100.07% and 99.0-100.50% for carbon paste electrode and glassy carbon electrode, respectively. The relative standard deviations were found in the following ranges: 0.636-1.395% and 0.431-1.104% in case of carbon paste electrode and glassy carbon electrode, respectively. Differential pulse voltammetry was successfully applied for the determination of repaglinide in tablets and human serum.