First-order kinetics Single-dose pharmacokinetics 8 8 First-order kinetics: 4 A constant fraction of the remaining amount 2 of drug is eliminated per unit time. 0 0 1 23 4 A Time (h) Zero-order kinetics Zero-order kinetics: A constant amount of drug is eliminated per 4 unit time. 2 0 0 1 2 4 Time (h) Zero Order Elimination:For drugs undergoing zero order elimination,a constant AMOUNT of drug is eliminated per unit time. dc =R dt Zero Order EliminationFirst-order kinetics: A constant fraction of the remaining amount of drug is eliminated per unit time. Single-dose pharmacokinetics Zero-order kinetics: A constant amount of drug is eliminated per unit time