Toxication, toxification or toxicity exaltation is the conversion of a chemical compound into a more toxic form in living organisms or in substrates such as soil or water. The conversion can be caused by enzymatic metabolism in the organisms, as well as by abiotic chemical reactions. While the parent drug are usually less active, both the parent drug and its metabolite can be chemically active and cause toxicity, leading to mutagenesis, teratogenesis, and carcinogenesis. Different classes of enzymes, such as P450-monooxygenases, epoxide hydrolase, or acetyltransferases can catalyze the process in the cell, mostly in the liver.
Parent non-toxic chemicals are generally referred to as protoxins. While toxication is generally undesirable, in certain cases it is required for the in vivo conversion of a prodrug to a metabolite with desired pharmacological or toxicological activity. Codeine is an example of a prodrug, metabolized in the body to the active compounds morphine and codeine-6-glucuronide.
Heavy metals are also the root cause for intoxication. Heavy metals such as lead, nickel, aluminium, cobalt, copper sometimes act as pseudo elements in biological system, the toxicity of heavy metal depends on the intake of the compounds present in the environment. Depending on the exposure and intake of the heavy metals there are two types of diseases i.e., acute and chronic. When a person starts accumulating heavy metals, leads to chronic disease like liver failure, heart diseases etc. Using pesticides is also one of the reason for the cause for toxication. Pesticides which possess elements like calcium, lead, copper, and zinc reside at the end of usage in the soil, which affects the fertility of the soil
Phase I of drug metabolism are bioactivation pathways, which are catalyzed by CYP450 enzymes, produce toxic metabolites and thus have the potential to damage cells. The unusual level of activity CYP450 enzymes might lead to the changes in drug metabolism and convert drugs into their more toxic forms.