Bio transformations & Xenobiotics
Biotransformation is the process that metabolize substances entering the body, such as drugs. It is the metabolic conversion of xenobiotic and endogenous chemicals to more water-soluble compounds. It is also known as Detoxification reaction. Generally, the physical properties of a xenobiotic are changed from lipophilicity (absorption) to hydrophilicity (excretion). Xenobiotic biotransformation is accomplished by a limited number of enzymes with broad substrate specificities. Lipid soluble drugs are poorly excreted in the urine. They tend to store in fat and/or circulate until they are converted (phase I biotransformation) to more water soluble metabolites or metabolites that conjugate (phase II biotransformation) with water soluble substances. Xenobiotics are biotransferred through any of the following reactions: Oxidation (Drugs, heavy metals), Reduction (Cosmetic Chemicals, heavy metals) and Hydrolysis (Drugs).