PSYC*3150 Lecture Notes - Lecture 4: Bioavailability, Neuroglia, Diazepam
Document Summary
Portion of original drug that reaches body fluid that gives drug access to site of action (soa) Absorption and distribution are foundations of bioavailability. Body parts that have most blood get most of drug: ex. Heart, brain, kidney, liver: other parts that have less blood flow like muscle, viscera and fat can take long to get blood. Diffusibility = rate at which substance enters system or interacts with another substance. Solubility = how easy a drug can be dissolved or entered into a solution: fat solubility of drug plays role in how much of it can reach brain. Blood-brain barrier: drugs has to cross bbb before brain, filters toxins, capillary wall pores in brain small and close so they restrict passage of substances through them. Think wall of glial cells encloses capillaries to form another line of defence: highly fat-soluble drug like valium can pass through capillary and glial cell membranes.
