title: Chelating drugs and zinc.
abstract: Essential trace metals participate in a wide range of biochemical processes. Administration of drugs containing nucleophilic atoms, primarily N-, O- and S-ligands, may result in formation of organometallic non-ionic complexes or chelates. The stability of the complex depends on the position of the metal in the first transition series, except for Cu2+, which forms stronger bindings than Zn2+ does. In nature, a wide range of chelates occur, e.g. as vitamin-metal complexes (Zn-thiamine, Zn-pyridoxamine and Zn-biotin). Phytate in unleavened grains forms unsoluble Zn-complexes. In the body, complex-formation is essential for the transport of Zn with circulating plasma albumin. Some examples of chelating drugs are given. Zn-pyrithione is used for local treatment of dandruff and pityrosporum folliculitis. Ethambutol is a strong metal-binding drug used for tuberculosis therapy. The mechanism of action is possibly related to inactivation of Zn and Cu in the pathogenic organisms. 8-hydroxyquinolines enhance Zn absorption, which is the reason for the successful treatment of acrodermatitis enteropathica. Effects of D-penicillamine, phenytoin, tetracycline and disulfiram on Zn metabolism are discussed.
mesh_terms: D000818:Animals; D002614:Chelating Agents / Q000494:pharmacology*; D004221:Disulfiram / Q000494:pharmacology; D004977:Ethambutol / Q000494:pharmacology; D006801:Humans; D009942:Organometallic Compounds; D015125:Oxyquinoline / Q000494:pharmacology; D010396:Penicillamine / Q000494:pharmacology; D010672:Phenytoin / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology / Q000627:therapeutic use; D051381:Rats; D013752:Tetracycline / Q000494:pharmacology; D015032:Zinc / Q000378:metabolism*
chemical_list: D002614:Chelating Agents; D009942:Organometallic Compounds; D011725:Pyridines; D015125:Oxyquinoline; D010672:Phenytoin; D004977:Ethambutol; D013752:Tetracycline; D010396:Penicillamine; D015032:Zinc; C010423:pyrithione zinc; D004221:Disulfiram