Pharmacokinetics III: Volume of Distribution

When an amount A of drug is administered intravenously (i.v.) the simple first order elimination model predicts an exponential decay with a single half life (t1/2) equal to ln(2)/K e , where K e is the rate constant for elimination. The value of ln(2) is approximately 0.693; thus, \({t_{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}}} \doteqdot {{0.693} \mathord{\left/ {\vphantom {{0.693} {{K_e}}}} \right. \kern-\nulldelimiterspace} {{K_e}}}\). This kinetic pattern has been discussed in Procedure 21.