The in vivo pharmacokinetic profile of disulfiram in patients is
complex and is incompletely understood. The initial cleavage of
the weak disulfide bond to form the corresponding diethyldithiocarbamate
anion (known as ditiocarb) is well established. It has been
postulated that the complex of ditiocarb with copper(II) ions (CuEt)
formed in the blood is likely to be responsible for the anticancer
activity of disulfiram.5 An alternative reported pharmacokinetic
pathway involves the formation of carbamo(dithioperoxo)thioates
(mixed disulfides derived from disulfiram, Fig. 1) following initial
formation of ditiocarb. Notably, carbamo(dithioperoxo)thioates
have been reported as inhibitors of human mitochondrial6 and
sheep liver7 ALDH, the therapeutic target on which clinical approval
of disulfiram is based.