TABLE 2.

Population estimates of the final model describing piperaquine population pharmacokinetics in fasting (n = 15) and fed (n = 15) patients with uncomplicated P. falciparum malaria in Thailand

Parameterd	Value
	Population estimatea (% RSEb)	95% CI for population estimateb	IIV (% CV)a (% RSEb)	95% CI for IIVb
Typical parameters
CL/F (liters/h)	67.6 (11.6)	54.0–85.5	24.4 (26.0)	17.4–29.6
VC/F (liters)	3,030 (16.4)	2,160–4,180	51.6 (32.3)	31.2–68.1
Q1/F (liters/h)	408 (15.0)	309–557
VP1/F (liters)	6,240 (14.6)	4,890–8,530	45.6 (48.8)	18.8–68.4
Q2/F (liters/h)	109 (13.6)	83.3–143	25.8 (48.2)	6.67–37.9
VP2/F (liters)	24,400 (10.1)	20,000–29,500
MTT (h)	2.04 (7.50)	1.80–2.41	24.1 (52.7)/39.4 (22.7)c	8.77–35.6/29.2–48.0
No. of transit comp.	3 (fixed)
F (%)	100 (fixed)		48.8 (16.6)c	38.3–56.0
σ (% CV)	30.7 (4.42)	27.8–33.5
Covariate effects
Dose effect on F (%)	25.3 (34.4)	9.82–53.2
Age effect on VP1 (%)	4.10 (18.1)	2.38–5.32

^aComputed population mean values from NONMEM. Interindividual variability (IIV), between-occasion variability, and random residual variability are calculated as 100 × $\sqrt{EXP\left({\sigma }^2\right)-1}$.

^bAssessed by the nonparametric bootstrap method (n = 1,000 iterations) for the final pharmacokinetic model. Relative standard errors (RSE) are calculated as 100 × (standard error/mean). Ninety-five-percent confidence intervals are displayed as the 2.5 to 97.5 percentiles of bootstrap estimates.

^cBetween-occasion variability.

^dCL, elimination clearance; V_C, central volume of distribution; Q, intercompartment clearance; V_P, peripheral volume of distribution; MTT, mean absorption transit time; No. of transit comp., number of transit compartments; F, oral bioavailability; σ, additive residual error; CV, coefficient of variation.