Here are some vocabulary words I learned yesterday...
toxicokinetics - how the body handles poisons
Absorption into the body
� As a general rule, fat soluble liquids are readily absorbed through the skin and fat soluble vapours are readily absorbed through the lungs. Notably these routes apply to organic solvents such as hexane, toluene, trichlorethylene and many others.
Distribution within the body
� Many factors affect the distribution of a toxic substance but water or fat solubility is very important. Thus for example water soluble compounds of lead are found (amongst other places) in the red blood cells, while fat soluble ones concentrate in the central nervous system (CNS).
The distribution of a toxic substance determines its concentration at a particular tissue and therefore the number and type of cells exposed to high concentrations of it.
Metabolism/ biotransformation of toxic substances
� Toxic substances may be converted into other substances (metabolites) by organs such as the liver and kidneys
� Thus non-polar and therefore not water soluble organic compounds tend to be oxidised within the liver e.g.:
o trichloroethane oxidised to trichloroethanol trichloroacetaldehyde and trichloroacetic acid
o dichloromethane (methylene chloride CH2Cl2) oxidised to carbon monoxide (CO)
� Water soluble metabolites are then more easily excreted by the kidney (see below)
� Metabolism or biotransformation does not necessarily result in less toxic compunds. For example benzene may be oxidised to an expoxide which then inflicts damage on the DNA in genes, i.e. it is genotoxic and thence carcinogenic
Routes of elimination of toxic substances / or their metabolites
� Kidneys - especially water soluble substances
� Lungs - especially fat soluble vapours e.g. - alcohols, or gases such as carbon monoxide
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3,4 methylenedioxymethamphetamine (MDMA) best known as "The Love Drug" or by its street name "X"
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biomimetic - the study of the formation, structure, or function of biologically produced substances and materials (as enzymes or silk) and biological mechanisms and processes (as protein synthesis or photosynthesis) especially for the purpose of synthesizing similar products by artificial mechanisms which mimic natural ones