Exploring the Electrochemistry of Surface-Active Redox Systems in Voltametric Analysis of Drug-Drug Interactions

Methylene blue is a model-like surface-active redox system, suitable to
study various effects related to chemical interactions involved in voltammetry of
surface electrode mechanisms. The redox transformation of methylene blue (MB)
described by 2e-/2H+, whereby MB switches between the oxidized form (blue-MB)
to a reduced form called leuko-methylene blue (MBH2).1 The voltammetric
patterns of methylene blue can be analyzed in a way to get access to
thermodynamics and kinetics of eventual interactions between MB/MBH2 and a
defined drug. By applying suitable theoretical models developed under square
wave voltammetry, it is possible to evaluate the mechanism, and also kinetic and
thermodynamic parameters of interaction between given drug and the electroactive
molecules of MB. In experimental protocol, all parameters are kept constant and
only concentration of the drug changes.2
Experimental Results: (A) Net SW voltammograms of methylene blue
recorded in absence and in presence of ibuprofen, (B) Net-SW voltammograms of
methylene blue recorded in absence of vitamin and in presence of vitamin C. Keywords: voltammetry, kinetics, thermodynamics, drug-drug interactions.