Guided by,K.charhate sir
presented by,priyanka R Todkari
M-PHARM(Q.A.)
1
1)INTRODUCTION.
2)FACTORS AFECTING BIOTRANSFORMATION OF DRUG.
- induction of drug metabolising
enzymes
- inhibition of drug metabolising
enzymes.
2
Biotansformation is the chemical
modification made by organism on a
chemical compound.
The chemical conversion of one form to
another is called as biotransformation of
drug.
3
The alteration of a substance within the
body as by action of enzymes is called
biotransformation.
The term is used synonymously with
metabolism.
4
Physicochemical properties of drug.
Biological factors.
chemical factors.
5
. 1) molecular size and shape, 2)pKa, 3)acidity/basicity, 4)steric and electronic characterestric of drug. 5)Stereochemical nature of drug.
& 6)Electronic characteristic of a drug
6
1) Species differences. 2 ) Strain differences. 3) Sex differences. 4)Age. 5)Diet. .6)Altered Physiochemical Factors- a)Preganacy; b)Hormonal Imbalance; c)disease status. 7)Temporal Factors
a)circardian Rhythm; b) circannual Rhythm.
7
1) Induction of drug metabolising
enzymes.
2) Inhibition of drug metabolising
enzymes
8
The phenomenon of increased drug
metabolising ability of the enzymes by
several drugs and chemicals is called as
enzyme induction.
The agents which bring about such
effect are known as enzyme inducers.
9
a)They are lipophilic compounds.
b) They are sustrate for the inducted
enzyme system.
c) They have long elimination half-lives.
10
a)Increase in both liver size and liver blood flow. b)Increase in both total and microsomal
protein content. c) incresed stability of enzymes. d) incresed synthesis of cytochrome P-450. e) decrease degradation of cytochrome
P- 450. f) proliferation smooth endoplasmic reticulum.
11
1)Phenobarbitol type inducer.
2)Polycyclic hydrocarbon type inducer.
12
a)Decrease in pharmacological activity
of drug.
b)Increased activity where the
matebolitesare active.
c)Altered physiological status due to
enhanced metabolism of endogenous
compounds such as sex harmones.
13
14
Inducer Drug with enhanced metabolism.
Barbiturates Coumarins,phenytoin,cortisol,oral
contraceptives.
Alchol Phenobarbital,coumarin
Phenytoin Cortisol,coumarin
Rifampicin Coumarin,tolbutamide
Cigarette Smoke Nicotine,amino azo dyes.
A decrease in the metabolisming ability of
an enzyme is called as enzymes
Inhibition.
It may be-
1)Direct Inhibition.
2) Indirect Inhibition.
15
It can occurs by one of 3 mechanism.
a) Competitive Inhibition.
b) Non-Competitive Inhibition.
c) Product Inhibition.
16
it is brought about by one of the two
mechanisms.
a) Repression.
b) Altered physiology.
17
Enzymes Inhibition is more clinically than
enzyme induction.
Some examples of inhibitors and drug
affected by them ,
18
Inhibitors Drugs with Decreased
Metabolism
MAO inhibitors Barbiturates,tyramine
Coumarin Phenytoin
Allupurinol 6-Mercaptopurine
PAS Phenytoin,hexobarbitol.
1)D.M.BRAMHANKAR; SUNIL
B.JAISWAL
Page no.140
19
20
Top Related