Simultaneous determination of mycophenolate mofetil and its active metabolite, mycophenolic acid, by differential pulse voltammetry using multi-walled carbon nanotubes modified glassy carbon electrode

• A new modified electrochemical sensor was constructed and used.
• Multiwalled carbon nanotubes were used as the modifiers.
• MPM and MPA were measured simultaneously at the low levels.
• The sensor was used to the determination of MPA and MPM in real samples.

A highly sensitive electrochemical sensor for the simultaneous determination of mycophenolate mofetil (MPM) and mycophenolic acid (MPA) was fabricated by multi-walled carbon nanotubes modified glassy carbon electrode (MWCNTs/GCE). The electrochemical behavior of these two drugs was studied at the modified electrode using cyclic voltammetry and adsorptive differential pulse voltammetry. MPM and MPA were oxidized at the GCE during an irreversible process. DPV analysis showed two oxidation peaks at 0.87 V and 1.1 V vs. Ag/AgCl for MPM and an oxidation peak at 0.87 V vs. Ag/AgCl for MPA in phosphate buffer solution of pH 5.0. The MWCNTs/GCE displayed excellent electrochemical activities toward oxidation of MPM and MPA relative to the bare GCE. The experimental design algorithm was used for optimization of DPV parameters. The electrode represents linear responses in the range 5.0 × 10− 6 to 1.6 × 10− 4 mol L− 1 and 2.5 × 10− 6 mol L− 1 to 6.0 × 10− 5 mol L− 1 for MPM and MPA, respectively. The detection limit was found to be 9.0 × 10− 7 mol L− 1 and 4.0 × 10− 7 mol L− 1 for MPM and MPA, respectively. The modified electrode showed a good sensitivity and stability. It was successfully applied to the simultaneous determination of MPM and MPA in plasma and urine samples.