Biotransformation into inactive product

- Bio-inactivation

Example: procaine is used for dental procedures and is metabolized locally by the enzyme pseudo-cholinesterase (hydrolysis). The result is two inactive compounds.

- Preparation for elimination

Example: paracetamol is metabolized primarily in the liver, where it undergoes conjugation with sulphate and glucuronide. The result is two inactive polar compounds ready

for renal elimination.

Biotransformation into active product

- Pro-drugs

Example: sulindac is an inactive compound that converted by liver enzymes to a sulphide. The result is an active NSAID.

- Active metabolites

Example: imipramine is a tricyclic antidepressant that is oxidized by microsomal enzymes in the liver to desipramine. The result is an equally effective tricyclic antidepressant.