Electrochemical behavior of an anti-cancer drug at glassy carbon electrode and its determination in pharmaceutical formulations

Capecitabine ( CPT) is an anticancer prodrug of 5- fluorouracil (5-FU) used in the treatment of colorectal and breast cancer. The electrochemical behavior of CPT at glassy carbon electrode was investigated by cyclic, linear sweep and differential pulse voltammetry (DPV). A well defined reduction peak of CPT at 4 x 10(-5) M was observed in Britton-Robinson (BR) buffer of pH 2.5. The reduction process was observed to be irreversible over the pH range of 1-7. The influence of different electrolytes, pH, scan rate and concentration of the drug on cathodic peak was studied. The probable reaction mechanism involved in the reduction of CPT was also proposed. A DPV method with good precision and accuracy was developed for the determination of CPT in pharmaceutical formulations. The peak currents were found to be linearly dependent on the concentration range of 8 x 10(-7) - 5 x 10(-5) M CPT. The limit of detection ( LOD) and limit of quantification ( LOQ) were noticed to be 1.13 x 10(-7) and 3.78 x 10(-7) M, respectively.