Drug metabolism | Med chem 4th sem | b pharmacy

DRUG METABOLISM 

It is defined as the chemical reactions that are responsible for the conversion of drug into another products before and after they have reached their site of action. Drug metabolism is also known as biotransformation.

Phase I Reactions :

• Oxidation 

• Reduction 

• Hydrolysis 

• Cyclization 

• Decyclization

(a) OXIDATION - 

• Addition of Oxygen or removal of Hydrogen.

• Oxidation 9 types :-

(b) Reduction -

Addition of hydrogen or removal of oxygen.

(i) Nitro reduction

(ii) Keto reduction

(c) Hydrolysis -

Drug is split combining with water.

(d) Cyclization -

Formation of ring structure from a straight chain.

(e) Decyclization -

Ring structure opened.

Phase II Reactions :

• Glucuronide conjugation 

• Acetylation 

• Methylation 

• Sulfate conjugation 

• Glycine conjugation 

• Glutathione conjugation

• Ribonucleotide / Ribonucleoside synthesis