Brief description of Chelating agents

1. CHE L ATING
AG E NTS
Dr. Kaushik Mukhopadhyay
AIIMS, Kalyani

2. Chelating agents
Chelating agents are drugs used to
prevent or reverse the toxic effects of a
heavy metal on an enzyme or other
cellular target, or to accelerate the
elimination of the metal from the
body.

3. Heavy metals -
mechanism
Reactions of Heavy metals with
sulphydryl groups of proteins or
enzymes
(A) = Intramolecular bonding;
(B) = Intermolecular bonding;
P = Protein; E = Enzyme; M =
Metal.
DOI: 10.5772/intechopen.82511

4. https://doi.org/10.1016/j.jtemb.2019.05.003

5. IDEAL
CHELATING
AGENTS
http://www.authorstream.com/Presentation/drmayur2511-1111072-chelating-agents/

6. Chelating agents and their uses
Review of Pharmacology – Garg & Gupta

7. Dimercaprol (British Antilewisite - BAL)
The two SH groups or dimercaprol bind those metals which produce their
toxicity by interacting with sulfhydryl containing enzymes in the body
2:1 complex is more stable
USE –
• Poisoning by As, Hg,Au, Bi, Ni, Sb
• Adjuvant to Cal. disod. edetate in lead poisoning
• Adjuvant to penicillamine in Cu poisoning and in Wilson's disease

8. Salt and chelate formation with edetate
(ethylenediaminetetraacetate, EDTA)
Katzung 14th Ed.

9. Calcium
disodium
edetate
Pharmacokinetics - It is highly ionized,
therefore distributed only extracellularly and
rapidly excreted in urine by glomerular
filtration, poor oral absorption
USE –
Lead poisoning,
Zn, Cd, Mn, Cu and some radioactive metals
ADR - proximal tubular necrosis,Acute febrile
reaction, anaphylactoid reaction

10. Penicillamine
It is dimethyl cysteine, obtained as a
degradation product of penicillin
D-isomer is used therapeutically, L-isomer
is toxic (optic neuritis)
Adequate oral absorption, minimal
metabolism, excretion via urine and faeces
USE –
• Wilson’s disease
• Copper/Mercury/Lead poisoning
• Cystinuria
• Scleroderma
ADR – Long erm - hematological, renal,
collagen tissue toxicity

12. Iron chelators

13. Iron chelators