Metal binding tendencies of various antibiotics

Abstract

Abstract A method to determine the presence of metal-drug complexes in dilute solutions is described. Using this method cycloserine was found to complex with cupric, nickelous, zinc and cobalt ions; streptomycin and novobiocin complexed with cupric ions; erythromycin complexed with cobalt ions, and chloramphenicol exhibited no metal binding tendencies. Various penicillins were found to interact with zinc and cupric ions. Preliminary investigations suggest that cupric ions, rather than simply complexing with penicillin as suggested by previous workers, promote the degradation of penicillin to penicilloic acid. Evidence is presented to confirm the presence of penicilloic acid in reaction mixtures initially containing penicillin G or V and cupric ions, and to establish that the reaction follows second order kinetics and ceases when all available cupric ion has been consumed. Good correlation was noted for these results and previous work which showed the effects of metal ions on the antibacterial properties of penicillin.