- Toxication
Toxication is the process of
metabolism in which the metabolite of a compound is more toxic than the parent drug orchemical .Toxication may involve:
- Changing the physicochemical properties to cause a change in the microenvironment
- Increasing the potency of a compound
- Conversion of the compound into:
- Electrophile
- Free radical
- Nucleophile
- Redox-active reactant
While toxication is generally undesirable, in certain cases it is required for the "
in vivo " conversion of aprodrug or chemical to a metabolite with desired pharmacological or toxicological activity.Codeine is an example of a prodrug, which is metabolized in the body to theopioid known asmorphine .Examples
The breakdown of
methanol in the mammalian liver. Methanol in itself is toxic due to itsCNS depressant properties, but acquires more dangerous toxicity through its metabolitesformic acid andformaldehyde , which can cause severeacidosis , damage to theoptic nerve , and other life-threatening complications.The metabolism of
paracetamol (acetaminophen) to the hepatotoxic metaboliteNAPQI via thecytochrome P450 oxidase system.Metabolic Activation of N-Hydroxy-2-aminofluorene and N-Hydroxy-2-acetylaminofluorene by Monomorphic N-Acetyltransferase (NAT1) and Polymorphic N-Acetyltransferase (NAT2) [ [http://cancerres.aacrjournals.org/cgi/content/abstract/53/3/509 Metabolic Activation of N-Hydroxy-2-aminofluorene and N-Hydroxy-2-acetylaminofluorene by Monomorphic N-Acetyltransferase (NAT1) and Polymorphic N-Acetyltransferase (NAT2) in Colon Cytosols of Syrian Hamsters Congenic at the NAT2 Locus - Hein et al. 53 (3): 509 - Cancer Research ] ]
Role of cytochrome P4501B1 in benzo [a] pyrene bio-activation to DNA-binding metabolitesEvidence from 32p-postlabeling for formation of 3-hydroxybenzo [a] pyrene and benzo [a] pyrene-3,6-quinone as major proximate genotoxic intermediates [ [http://jpet.aspetjournals.org/cgi/content/abstract/jpet.102.044271v1 Role of cytochrome P4501B1 in benzo [apyrene bio-activation to DNA-binding metabolites in mouse vascular smooth muscle cells: Evidence from 32p-postlabeling for formation of 3-hydroxybenzo [apyrene and benzo [apyrene-3,6-quinone as major proximate genotoxic intermediates - Moorthy et al., 10.1124/jpet.102.044271 - Journal of Pharmacology And Experimental Therapeutics ] ]
References
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