Description of the Module
Users of crack cocaine are more likely to become addicted than users of snorted cocaine. How can the same compound produce these differences in behavior? The answer lies in its pharmacokinetics, which describes the rate of distribution of drugs throughout the body. This module contains a combination of basic biology and chemistry principles to demonstrate several phenomena; 1) how the acid-base characteristics of cocaine enable it to be dissolved in aqueous solution or volatilized in smoke, 2) how the acid-base characteristics of cocaine enable it to pass through a biological membrane, 3) how the composition of a biological membrane affects the ability of a charged vs. uncharged molecule to pass through, 4) how the connections between the circulatory system and the lungs govern the speed at which drugs are delivered to the brain, and 5) how the organism responds to psychoactive drugs that enter and leave the brain quickly vs. those that enter slowly and persist longer.