bioprecursors
Post on 31-Dec-2015
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Bioprecursors
• Bioprecursors result from a molecular modification of the active principle itself. This modification generates a new compound, able to be a substrate for the metabolizing enzymes (often, oxidation and reduction). The metabolite being the expected active principle.
)i (Bioactivation
• Hydroxylation of cyclophosphamide
(anticancer agent) followed by metabolite
decomposition converts the prodrug to the
cytotoxic phosphoramide mustard.
• the activation involved oxidative dealkylation followed by a spontaneous hydrolysis to the parent active nitrogen mustard.
)ii (N-dealkylation
• Diazepam is converted to the active metabolite by N-dealkylation
)iii (O-dealkylation• The analgesic phenacetin acts in the form of
its dealkylated derivative, acetaminophen
)iv (Reduction
• The non-steroidal anti-inflammatory drug sulindac is reduced in vivo to the active form
)v (Selective bioactivation
• The insecticide, Malathion (acetylcholinesterase inhibitor), is desulfurized selectively to the toxic Malaoxon, but only by insect and not mammalian enzymes, Malathion is, therefore, Relatively non-toxic to mammals.
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