Electrochemical mechanism and sensitive assay of antiretroviral drug Abacavir in biological sample using multiwalled carbon nanotube modified pyrolytic graphite electrode

Multiwalled carbon nanotube modified edge plane pyrolytic graphite electrode (MWCNT/EPPGE) was developed and implemented for the determination of antiretroviral drug Abacavir using differential pulse adsorptive stripping voltammetry (DP AdSV). Cyclic voltammogram showed two oxidation peaks located at +0.91 V and +1.10 V on (MWCNT/EPPGE). Dependency of peak potential and peak current on pH was investigated as details. The oxidation potentials affected by the pH indicating protons are involved in the electrochemical oxidation of Abacavir. Mass transport to the electrode surface was found as a combination of diffusion and adsorption which was concluded by studying the potential scan rate dependency of both peak currents. The oxidation mechanism was proposed using the obtained data and discussed. A large enhancement in both of the peak currents was observed with applying an accumulation step presenting the effect of adsorption. Peak currents showed a linear relation upon the Abacavir concentration within a range of 1 × 10−7-2 × 10−5 M with (r = 0.999) for both peak responses. The method was fully validated related with selectivity, sensitivity, precision and accuracy studies. Abacavir was also determined with the proposed method in its pharmaceutical dosage forms and human serum samples. No interferences from the excipients of the dosage form or endogenous substances from biological material were found.