drug metabolism phase 1 reactions phase 2 reactions oxidation, reduction, hydrolysis, glucuronidation, glycine conjugation, sulfate conjugation factors affect drug metabolism

1. Drug Metabolism
Prepared
By:
Aditi
Assistant Professor
School of Pharmacy
MMUS, AmbalaDrug metabolism and liver

2. Drug metabolism defines the reactions faced by a drug while present in the body.
The drug metabolism is the metabolic breakdown of drugs by living organisms,
usually through specialized enzymatic systems.
These biotransformations occur in the liver, kidney, intestine, lungs, skin etc.

3. Phases of Metabolism
There are two phases of drug metabolism.
Phase I Phase II
Oxidative
Reduction
Hydrolysis
Glucuronidation
Glutathione conjugation
Sulfate conjugation
Amino Acid Conjugation
Methylation
Acetylation

4. The most common and important enzyme group involved in the Phase I metabolism of
drugs is the cytochrome P450 (CYP450) superfamily of enzymes. This group of
enzymes acts as a catalyst for the oxidation of many drugs. This group can also be
induced or inhibited by many drugs and other substances. This is what is known as a
drug interaction. Important enzymes in this family include:
● CYP1A2
● CYP2C9
● CYP2C19
● CYP2D6
● CYP2E1
● CYP3A4

5. OXIDATIVE reactions
A) Oxidative reactions involving Carbon- carbon linkage
● Examples of drugs having aromatic moieties.
● Drugs having Olefinic bond
● Drugs having Benzylic carbon: Tolbutamide
● Drugs having Allylic carbon atom: Quinidine
● Carbon atom no 1 attached to the carbonyl group: Diazepam
● Drugs having Aliphatic carbon atom: Valproic acid, Ibuprofen
B) Oxidative reactions involving Carbon- heteroatom linkage
● Drugs having carbon-nitrogen system: Diazepam, Dapsone, Imipramine,
lignocaine, Amphetamine
● Drugs having carbon-oxygen system: Paracetamol
● Drugs having carbon- sulphur system: Chlorpromazine, Thiopentone

6. REDUCTIVE reactions
HYDROLYTIC reactions
A) Drugs having nitro, azo, and carbonyl groups: Sulphanilamide, Clonazepam,
Progesterone, Sulindac, Halothane
A) Drugs having ester functionality: Procaine

7. Glucuronidation reactions
Sulfate conjugation reactions
Glutathione conjugation reactions
Drugs with alcohol, Phenols, amines functionalities: desipramine, methimazole
Examples of drugs: Steroids, and phenolic drugs
Drugs having polycyclic phenols and halides: Ethacrynic acid

8. Glycine and Glutamic acid conjugation reactions
Methylation reactions
Acetylation reactions
Examples of drugs: Carboxylic acid containing drugs
Examples of drugs: Dopamine, Norepinephrine
Examples of drugs: Sulpha drugs, aromatic amine (Hydralazine, Isoniazid)

9. FACTORS AFFECTING DRUG METABOLISM
https://www.google.com/search?q=factors+affecting+the+drug+metabolism&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjhpqzO2OnfAhXEiHAKHf40B3YQ_AUIDigB&biw=1366&bih=657#imgrc=rAHam1NzL5MLeM:

10. THE END