BIOTRANSFORMATION , EXCRETION OF DRUG AND DETOXIFICATION

Contents

Introduction regarding DetoxificationBiotransformation DefinitionProcessSite of biotransformationPhase I/Phase II reactionsDrug metabolising enzymesFirst pass metabolismDrug EliminationDrug Excretion

Introduction regarding DetoxificationDetoxification definition:The metabolic process by which toxins are changed into less toxic or more readily excreted substances.

Why is it required???Steps for detoxification of drugs in bodyBiotransformation- metabolismDrug eliminationDrug excretion

Site of Biotransformation

Factor Affecting Drug Metabolism

Age Disease Species Differences Gender Pregnancy Environmental Drug Dose Enzyme Induction Enzyme Inhibition Diet Heredity/GeneticsDRUG METABOLISM

Classification of Biotransformation Reactions

conclusion

First Pass Metabolism

DRUG ELIMINATIONElimination of a drug

First order zero order

Plasma half-life The Plasma half-life of a drug is the time taken for its plasma concentration to be reduced to half of its original value.elimination t1/2 is t1/2 = k

DRUG EXCRETIONUrine : Through kidneysGlomerular Filtration:-Tubular ReabsorptionTubular secretion

Faeces : - eg. Erythromycin, ampicillinAir :eg- general anesthetics, paraldehyde Saliva and sweat:-eg. Lithium , thiocyanates, rifampin Milk :-more lipid soluble and less protein boundHofmann elimination ByDr. Ritu MathurDate 27 th august, 2013