Calcium channel blocker lercanidipine electrochemistry using a carbon black-modified glassy carbon electrode

Lercanidipine, a third-generation dihydropyridine calcium L-type channel blocker, redox behavior at different carbon electrode materials, in a wide pH range, using cyclic, square-wave, and differential pulse voltammetry, was studied. A comparison was made between unmodified glassy carbon electrode (GCE) and boron-doped diamond electrode (BDDE), and GCE and BDDE modified with a carbon black (CB) nanoparticle embedded within a dihexadecylphosphate (DHP) nanostructured film (CB-DHP/GCE and CB-DHP/BDDE). Lercanidipine oxidation, for 3.4 < pH < 9.5, is an irreversible, diffusion-controlled, pH-dependent process that occurs in two consecutive steps, with the transfer of one electron and one proton, at the N1 and C4 positions in the 1,4-dihydropyridine ring. For pH > 9.5, both oxidation processes are pH-independent and a pKa = 9.40 was determined. Lercanidipine reduction at pH = 7.0 is an irreversible process, and the lercanidipine reduction products are electroactive and follow a reversible electron transfer reaction. Lercanidipine electroanalytical determination, at a nanostructured GCE modified with a CB-DHP film (CB-DHP/GCE), with no need for N2 purging, with a detection limit of 0.058 μM (3.58 × 10^-5 g L^-1) and a quantification limit of 0.176 μM (1.08 × 10^-4 g L^-1), was achieved. Graphical abstract.