Rates & Orders of Reactions Dr. Muslim Suardi, MSi., Apt. Faculty of Pharmacy University of Andalas

Rate “The rate of a chemical reaction of process is the velocity with which the reaction occurs” Drug A Drug B If the amount of drug A is decreasing with respect of time, the rate of reaction: -dA/dt

Rate constant The order of reaction refers to the way in which the concentration of drug or reactants influences the rate of a chemical reaction Zero-order Reactions First-order Reactions Second-order Reactions

Zero-order Reaction dA/dt = -k 0 Integration A = -k o t + A 0 C = -k o t + C 0

First-order Reaction dA/dt = - kA Integration ln A = -kt + ln A 0 A = A 0 e -kt C t = C 0 e -kt

Second Order Reaction dC/dt = -KC 2