Chelating Agents Medicinal Chemistry 1.pptx

Chelating agents, also known as chelators, are chemical compounds that form stable, water-soluble complexes with metal ions. They play a crucial role in medicinal chemistry by influencing metal homeostasis in biological systems, detoxifying heavy metals, and serving as therapeutic agents in various medical conditions. The structure of chelating agents is characterized by multiple binding sites, typically donor atoms such as nitrogen, oxygen, or sulfur, which coordinate with metal ions to form ring-like structures called chelates. This multi-dentate coordination significantly enhances the stability of the complex compared to a simple metal ion-ligand interaction.

Chelating agents are essential in treating metal poisoning, which can lead to severe health issues such as neurological damage, renal dysfunction, and carcinogenic effects. Chelators like dimercaprol, dimercaptosuccinic acid (DMSA), and EDTA are used to bind toxic metals, forming complexes that are more easily excreted from the body via renal or fecal routes, reducing their bioavailability and toxicity.

In addition to detoxification, chelating agents have therapeutic roles in managing diseases where metal ions are involved in the pathology. For example, penicillamine and trientine are used in Wilson's disease to remove excess copper from tissues, preventing hepatic and neurological damage. In oncology, chelators like gallium nitrate are used to treat hypercalcemia associated with malignancy by inhibiting bone resorption and disrupting iron metabolism within tumor cells.

Chelating agents also serve as diagnostic tools in medical imaging, with radiolabeled chelates used in nuclear medicine for imaging organs such as the heart, bones, and kidneys. In drug development, chelating agents serve as valuable scaffolds for the design of novel therapeutics, particularly in treating neurodegenerative diseases like Alzheimer's and Parkinson's.

The safety profile of chelating agents is paramount, as indiscriminate chelation of essential metals can lead to adverse effects. The therapeutic potential of chelating agents continues to expand as research uncovers new applications and mechanisms of action.

1. MEDICINAL CHEMISTRY -I Preetham Anton A PSG College of Pharmacy CHELATING AGENTS

2. The ability of a chemical compound to elicit a pharmacological/ therapeutic effect is related to the influence of various physical and chemical (physicochemical) properties of the chemical substance on the bio molecule that it interacts with.

3. TITLE OF CONTENTS

4. TYPES PHYSICAL PROPERTIES Physical property of drug is responsible for its action Eg: Castor Oil CHEMICAL PROPERTIES The drug react extracellularly according to simple chemical reactions like neutralization, chelation, oxidation etc. Eg:Mg(OH)2

5. TERMINOLOGY The compounds that are obtained by donating electrons to metal ion with the formation of a ring structure are called chelates. The compound capable of forming a ring structure with metal ion termed as ligands Chelation is the formation of multiple coordination bonds between organic molecules and a transition metal ion leading to sequestration of the metal.

6. IMPORTANCE OF CHELATES IN MEDICINE (a)Antidote for metal poisoning The chelation phenomena are used in medicine to remove toxic metal form the body.

7. DIMERCAPROL IS A CHELATING AGENT. IT IS AN EFFECTIVE ANTIDOTE FOR ORGANIC ARSENICAL AND ALSO USED TO TREAT POISONING BY GOLD AND ARSENIC

8. PENICILLAMINE USED IN WILSON'S DISEASE BECAUSE IT FORMS WATER SOLUBLE CHELATES with copper Wilson's disease is a rare genetic disorder that causes copper to build up in the body, leading to liver and brain damage. Symptoms include fatigue, abdominal pain, tremors, and difficulty speaking. It is treated with medication to remove excess copper from the body.

9. Water-soluble ligands are referred as sequestering agents. Certain drug, eg. Epinephrine and ascorbic acid are destroyed by oxidation and metals catalyze this oxidation. Common sequestering agents EDTA is used which forms a water-soluble ligand. (B) REMOVAL OF METALS CAUSING DETERIORATION IN PHARMACEUTICALS

10. A side effect of Hydralazine a antihypertensive agent is formation of anemia and this is due to chelation of the drug with iron. (C) UNDESIRABLE SIDE EFFECTS CAUSED BY DRUGS, WHICH CHELATES WITH METALS (D) 8-HYDROXYQUINOLINE AND ITS ANALOGS ACTS AS ANTIBACTERIAL AND ANTIFUNGAL AGENT BY complexing with iron or copper.

11. MECHANISM OF CHELATION Ligand-metal

12. APPLICATIONS OF CHELATION IN MEDICINAL CHEMISTRY

13. CHALLENGES IN CHELATION

14. TEXT BOOK OF MEDICINAL CHEMISTRY- Volume -I V.Alagarsamy TEXT BOOK OF MEDICINAL CHEMISTRY- Volume -I k.Ilango P.Valentina

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