The relationship of the pharmacokinetics of chloroquine to dose in the rabbit.

Four albino rabbits were treated with 4 different doses of chloroquine phosphate (30-50 mg kg-1) given intragastrically and 10 others were given the hydrochloride (2.5-12.5 mg kg-1 i.v.). The i.v. doses were given as bolus into the median ear vein over 5-8 min. Samples (3-5 mL) of whole blood were subsequently collected at intervals for up to 6 weeks and analysed by HPLC. From the results, log concentration-time curves were drawn and the i.v. data fitted by computer to 3-compartment (8 rabbits) or 2-compartment curves (2 rabbits). The area under the curve (AUC) and half-lives were calculated for the different doses. A plot of AUC versus dose yielded a straight line but the half-lives showed wide inter-individual variation from the same doses.