pharmacology consist to main part that its pharmacodynamic and pharmacokinatic, pharmacokinatic consist of four stages that is absorbtion, distrbution, metabolism and elimination. this presentation is about metabolism its very short disicription about metabolism of drug in the body.

1. Pharmacy 5rd semester
Pharmacology
By:Peshawa Ibrahim
Prof: Kareen

2. Metabolism or
Biotransformation
 It is enzymatic conversion from one chemical form of
substance to another.
 Metabolism is an essential pharmacokinetics process, which
converts lipid soluble and non-polar compounds to water
soluble and polar compounds so that they are excreted by
varies process.
 This is because only water soluble substances undergo
excretion, whereas lipid soluble substances are passively
reabsorbed from renal or extra renal excretory sites into the
blood by virtue of their lipophilicity.
 Biotransformation: it is a specific term used for chemical
transformation of xenobiotics in the body/living organism.

3. xenobiotics
 Xenobiotics: these are all chemical substances that
are not nutrient for body (foreign for body) and which
enter the body through ingestion, inhalation or dermal
exposure.
 They include:
 Drugs, industrial chemical, pesticides, pollutant, plant
and animal toxins…

5. Site/Organs of drug metabolism
 The major site of drug metabolism is the liver.
 Secondary organs of biotransformation
 1-Kidney
 2-lungs
 3-tests
 4-skin, intestins.

6. Cytochrome P450
Nomenclature
Cytochrome P450 is a family of
CYP., consist too many CYP.
For example
CYP1A2 metabolise caffeine
CYP2E1 metabolise alcohol

7. Metabolism
 Phase I – functionalization reactions
 Phase II – conjugation reactions

8. Phase I – functionalization
reactions
Includes: oxidation, reduction, hydrolysis, hydration and
isomerization…
- Converts the parent drug to a more polar metabolites
by introducing a functional group (-OH, -NH2, -SH)

9. Phase II (conjugation reactions)
True detoxification of drugs
 Occurs mostly in cytosol.
 Covalent bonding is formed between a functional
 group metabolite and an endogenous substrate.
 Highly polar – rapidly excreted in urine.
 Usually inactive except : morphine

10. conjugation
 Glucuronide Conjugation - the most common single
metabolic reaction for compounds with a hydroxyl or
carboxylic acid groups
 Sulfate Conjugation - catalyzed by a family of
enzymes known as ‘sulfotransferases’
 Acetylation - is catalyzed by enzymes ‘N-
acetyltransferases’
 Methylation - is catalysed by enzyme ‘methyl-
transferases’
 Glutathione Conjugation - important pathway in the
detoxification of a large variety of chemical toxic
substances
 Glycine Conjugation pathway to inactivate certain
drugs having carboxylic acid groups

14. FACTORS AFFECTING DRUG
METABOLISM
Age
Nutritition
Disease Condition
Pregnancy
Hormonal Effects
Effects of the Intestinal Microflora
Pharmacodynamic Factors

15. Thank you for listening
Peshawa mangury