The binding of metal ions by captopril (SQ 14225). Part I. complexation of zinc(II), cadmium(II) and lead(II)

Abstract A number of side effects have been observed in the use of captopril therapy. Many of these symptoms are typical of trace element deficiency and it seems probable that this agent complexes metal ions in vivo . Investigations into the interactions of captopril with Zn(II), Cd(II) and Pb(II) ions are carried out using glass electrode potentiometry under conditions of 37 °C, 150 mmol dm −3 NaCl. The formation constant data are then used in computer simulation models to investigate the mobilisation of these metal ions by captopril in normal plasma. It is shown that mobilisation is unlikely at pharmacological levels of the drugs, and therefore side effects are probably not directly dependent on mobilisation of these metals.