PHC 222Medicinal Chemistry-1-

Part(I)Dr. Huda Al Salem

Lecture (1)

Basic Medicinal Chemistry Terminology

You are going to study the following:1 -Drug: definition, sources, Meaning of SAR,

Nomenclature & classification

2 -Receptor: definition, sources & types

3 -Drug-Receptor Interaction: examples, affinity, efficacy, agonist, antagonist & pharmacophore.

I- DrugDrug is a pharmacologically active compound which is used to prevent and/or treat diseases

Sources of drugs1 -Natural sources: drugs obtained from plants, marine &

microorganisms such as :

opium shellfish

penicillium fungi

I- Drug

2 -Synthetic sources: by production & screening of structural analogues of the lead compound

such as : procaine(local

anesthetic)

cocaine

I- Drug

Structural analogue

Is a compound having a structure similar to that of another one, but differs from it in respect of a certain component.

Lead compound

Is a pharmacologically active compound whose chemical structure is used as a starting point for chemical modifications.

Structure-Activity Relationship (SAR)

Is the relationship between the structure of a particular compound or a group of compounds and its (their) biological activity.

I- DrugNomenclature of drugs

1 -Chemical name: It represents the exact chemical structure of the drug

2 -Generic name: the name which is chosen by official agencies e.g. WHO

3-Trade name: the name that is given by the manufacturer(company)

Paracetamol

Panadol, Adole

N-(P-hydroxyphenyl) acetamide

I- Drug

Another example..

-,VRSURS\ ODP LQR- - -QDSKWK\ OR[ \ - -SURSDQRO

Propranolol

Inderal

I- DrugClassification of drugs

1 -Pharmacological action: analgesic, antihypertensive

2 -Target system: adrenergic, cholinergic…etc

3-Chemical structure: penicillins, alkaloids…etc

4 -Mechanism of action at molecular level:Anticholinestrases, - b blocker….etc

II-Receptor

II-Receptor

Receptor is an integral biological macromolecule embedded in the biological system .

Sites of receptor could be..Cell membrane, cytoplasm or cell nucleus.

Components of receptor could be..Lipids,Proteins,

CarbohydratesOr Nucleic acids

II-Receptor

Types of receptors:

1. Structural and functional component of a cell membrane which consists of lipoprotein e.g. Ion channels.

2. Enzymes e.g. Acetylcholeinestrase & carbonic anhydrase

3. Non enzymatic protein receptors.. e. g. Adrenergic receptors

4. Receptors of nucleic acid e.g. DNA & RNA

II-Receptor

The receptor binds to a specific molecule (ligand) and initiates the cellular response to this molecule.

Role of Receptor

II-Receptor

L R+ L-R Complex

Biological Response

LigandIs a specific molecule that forms a complex with the receptor to give a biological response