Fate of chemicals following exposure II: Distribution

Distribution is the net result of the processes by which absorbed chemicals are carried from the site of absorption to various organs of the body where they may produce an effect, be stored, or eliminated. Distribution of chemicals is greatly affected by physicochemical properties determining affinity to specific tissues in the body (e.g., lipophilicity), binding to plasma protein, especially albumin, blood perfusion of the organ, and mass of the organ. The distribution of chemicals varies from person to person depending upon the body composition (e.g., lean vs. obese, age). In the brain, distribution of chemicals is tightly regulated by the blood-brain barrier. Placenta also acts as a barrier to the distribution of chemicals into developing embryos and fetuses.