Electrochemical evaluation of the interaction between ascorbic acid and the cardiotonic drug RS-82856

The solution phase interaction between ascorbic acid and the cardiotonic drug N-cyclohexyl-N-methyl-4(7-oxy 1,2,3,5-tetrahydroimidazol[2,1-b] quinazolin-2-one butyramide (RS-82856) was evaluated using a differential pulse voltammetric technique. Shifts in the peak potential of ascorbic acid to higher energy as well as decreases in peak current values were monitored as a function of RS-82856 concentration. The electrochemical data were obtained under conditions where both the drug and the ascorbic acid concentrations exhibited linear relationships with peak current values. The methodology was extended to the study of two other structurally related phosphodiesterase inhibitors cilostamide and anagrelide. The complexation of these drugs with ascorbic acid were also characterized by decreases in the diffusion currents of ascorbic acid as well as by anodic shifts in the peak potential. The significance of these observations may be related to the inhibition of cyclic nucleotide phosphodiesterase activity by both the drugs tested and the ascorbic acid.