 Biochemical alteration of chemicals such as (but not
limited to) nutrients, amino acids, toxins, and drugs
in the body
...
 Site : usually liver
 Enzymes:
MICROSOMAL ENZYMES
 A group of enzymes
associated with a certain
particulate fraction of liver
homogenate.
 These are a ...
Phase I
• Includes oxidative, reductive, and hydrolytic reactions.
• In these type of reactions, a polar group is either i...
 Oxidation
 Reduction
 Hydrolysis
 Process of addition of oxygen or removal of
hydrogen from a drug molecule.
• Phenytoin hydroxyphenytoinhydroxylation
• ...
 Addition of hydrogen or removal of oxygen
from a drug molecule.
 Nitro reduction :
chloramphenicol  arylamine
 Keto r...
 Process where a drug molecule is split by the
addition of a molecule of water.
 Both microsomal and non-microsomal
enzy...
 Most common type of metabolic reaction
 Drug + UDPGA drug
glucuronide + UDP
Glucuronyl transferase
excreted
Glutathione –s –
transferase
Enzyme : sulfotransferases
Biotransformation
Biotransformation
Biotransformation
Biotransformation
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Biotransformation

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Biotransformation

  1. 1.  Biochemical alteration of chemicals such as (but not limited to) nutrients, amino acids, toxins, and drugs in the body  It is also needed to render nonpolar compounds polar so that they are not reabsorbed in renal tubules and are excreted.  The body typically deals with a foreign compound (DRUGS) by making it more water-soluble, to increase the rate of its excretion through the urine
  2. 2.  Site : usually liver  Enzymes:
  3. 3. MICROSOMAL ENZYMES  A group of enzymes associated with a certain particulate fraction of liver homogenate.  These are a mixed function oxidase system or monooxygenases.  These requires NADPH and oxygen. NON MICROSOMAL ENZYMES  These are present in the cytoplasm and mitochondria of hepatic cells as well as in other tissues including plasma. The 2 most imp. Microsomal enzymes: 1. NADPH cyt. P450 reductase 2. Cut. P450
  4. 4. Phase I • Includes oxidative, reductive, and hydrolytic reactions. • In these type of reactions, a polar group is either introduced or unmasked, so the drug molecule becomes more water-soluble and can be excreted. • Reactions are non-synthetic in nature and in general produce a more water-soluble and less active metabolites Phase II • These reactions involve covalent attachment of small polar endogenous molecule such as glucuronic acid, sulfate, or glycine to form water-soluble compounds. • This is also known as a conjugation reaction. • The final compounds have a larger molecular weight.
  5. 5.  Oxidation  Reduction  Hydrolysis
  6. 6.  Process of addition of oxygen or removal of hydrogen from a drug molecule. • Phenytoin hydroxyphenytoinhydroxylation • Codeine  morphinedealkylation • Cimetidine  cimetidine sulfoxideS-oxidation • Amphetamine benzylmethylketonedeamination
  7. 7.  Addition of hydrogen or removal of oxygen from a drug molecule.  Nitro reduction : chloramphenicol  arylamine  Keto reduction: cortisone  hydrocortisone
  8. 8.  Process where a drug molecule is split by the addition of a molecule of water.  Both microsomal and non-microsomal enzymes maybe involved.  Eg: acetylcholine+ H2O  choline + acetic acid
  9. 9.  Most common type of metabolic reaction  Drug + UDPGA drug glucuronide + UDP Glucuronyl transferase excreted
  10. 10. Glutathione –s – transferase
  11. 11. Enzyme : sulfotransferases

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