Chelating Agents Flashcards
What are chelating agents
Molecules with 2 or more electronegative groups used to prevent or reverse the toxic effects of heavy metals on enzyme
What determines the efficiency of the chelator agents
Efficiency depends on the number of ligands/functional groups available for metal binding
Properties of an ideal chelating agent
Water Solubility
Resistant to metabolic degradation
Ability to penetrate sites of metal storage
Readily excreted
Low affinity for Ca2+
Ability to retain its chelating properties at the pH of bodily fluids
Classification of chelating agents
Basis: Number of ligands
Monodentates
Bidentates
Polydentates
How can chelators cause toxicity
They may chelate essential metals as they are non specific
Example of monodentates
Sodiumthiocarbazone
Diphenylthiocarbazone
Example of Bidentates
Bimechaprol
Penicillinamine
Polydentates
Edetate calcium disodiumtrientene
MOA of dimercaprol
Interacts directly with metals in the blood, tissue and reactivates cellular Sulfurhydryl containing enzymes following metallic poisoning
Adverse effects of dimercaprol is reversed with
Atropine
Adverse effects of dimercaprol
Hypertension
Tachycardia
Headache
Vomiting
The major advantage of penicillamine is
The suitability for chronic oral administration
Dextro-penicillamine is supplied in ……… and the initial dose is ………
250mg
250mg 4times daily
What limits the use of EDTA as a chelating agent
Invivo chelating of essential calcium
The side effect of EDTA in high doses
Hepatotoxicity
