Pharmacokinetics of piperaquine after single and multiple oral administrations in healthy volunteers.

The aim of this work was to study the pharmacokinetics of piperaquine in healthy volunteers. Healthy volunteers received piperaquine and tablets of Artekin by oral administration. The plasma samples were analyzed for piperaquine by liquid-liquid extraction and determined by HPLC-UV. The results demonstrated that the plasma drug concentration-time curves of single and multiple dose of piperaquine were fitted to a two-compartment open model. The pharmacokinetics parameters of piperaquine alone in a single dose were: t(1/2(beta))=(317.2-/+126.6)h, AUC(0-->infinity)=(44293-/+12636)h x ng/ml, V(d)=(9490.9-/+2161.9)ml/kg, and Cl=(22.83-/+9.83)ml/h/kg. In Artekin in a single dose these parameters were: t(1/2(beta))=(302.8-/+180.7)h, AUC(0-->infinity)=(46419-/+13670)h x ng/ml, V(d)=(10188.6-/+3520.3)ml/kg, and Cl=(25.48-/+10.89)ml/h/kg, while in Artekin in multiple doses they were: t(1/2(beta))=(298.9-/+101.9)h, AUC(0-->infinity)=(227692-/+56294)h x ng/ml, V(d)=(5031.5-/+1097.8)ml/kg, Cl=(11.91-/+3.046)ml/h/kg, respectively. The absorption and distribution of piperaquine were quick while the elimination was quite slow. There were significant differences in the pharmacokinetics parameters of piperaquine in Artekin between a single dose and multiple doses (p<0.001), suggesting that piperaquine might accumulate in vivo and that attention should be given to its possible adverse drug reactions in clinical treatment.