Erratum: Pharmacokinetics of Sulfadoxine and Pyrimethamine for Intermittent Preventive Treatment of Malaria During Pregnancy and After Delivery

CPT: Pharmacometrics Syst. Pharmacol. (2017) 6, 430–438; https://doi.org/10.1002/psp4.12181; published online 9 June 2017.

In [1], we noticed the units for the pyrimethamine additive error in Table 2 and the right‐hand side panel (sulfadoxine) of Figure 2 were incorrect. The correct units for the pyrimethamine additive error in Table 2 is ng/mL and the correct units for the right‐hand side panel (sulfadoxine) of Figure 2 is μg/mL. The corrected table and figure are shown below.

Table 2.

Final pharmacokinetic parameter values for pyrimethamine and sulfadoxine during pregnancy and after delivery

Parameter	Sulfadoxine		Pyrimethamine
	Estimate	95% CI a	Estimate	95% CI a
F	1 FIXED	—	1 FIXED	—
CL/F during pregnancy [L/h] b	0.0303	0.0185, 0.0349	1.35	1.12, 1.38
Vc/F [L] b	14.1	13.2, 14.4	163	151, 166
ka [/h]	0.531	0.464, 0.565	1.31	1.11, 2.70
Qp1/F [L/h] b	0.0252	0.0136, 0.0269	1.45	0.72, 1.61
Vp1/F [L] b	179	82, 212	29.8	23.9, 32.1
Qp2/F [L/h] b	—	—	0.122	0.064, 0.166
Vp2/F [L] b	—	—	251	142, 317
θRBC/PL [fraction of one]	0.155	0.023, 0.189	0.324	0.106, 0.525
Change in CL when non‐pregnant [%]	−75.7	−88.7, −66.6	21.2	12.3, 24.9
T50 [weeks]	6.35	5.47, 6.75	—	—
γ – shape factor	4.90	2.90, 7.41	—	—
Difference in clearance in Mozambique [%]	—	—	−20.2	−28.4, −17.4
Site effect (scaling on observations) in Mozambique [%]	21.2	8.2, 24.6	57.6	41.5, 60.6
Site effect (scaling on observations) in Sudan [%]	15.5	4.8, 20.0	33.2	19.6, 35.6
Site effect (scaling on observations) in Zambia [%]	−24.8	−30.7, −22.2	−5.40	−12.1, −3.9
Between subject variability in CL [%] c	31.3	21.8, 51.2	12.3	7.1, 16.9
Between occasion variability in F [%] c	20.7	16.7, 22.9	17.6	12.9, 21.5
Between occasion variability in CL [%] c	—	—	16.9	11.8, 22.3
Between occasion variability in ka [%] c	56.4	42.4, 70.1	—	—
Correlation in bioavailability of the two drugs [%]	67.9	55.9, 71.9	*	*
Additive error [ng/mL pyra – and µg/mL for sulfa]	2.13	2.00, 2.21	2.45	2.01, 2.68
Proportional error [%]	17.0	14.8, 17.5	18.0	15.1, 18.7
Correlation in random unexplained error of the two drugs [%]	61.3	54.2, 63.9	*	*

Pharmacokinetic parameter values are expressed referring to plasma. CI, confidence interval; F, relative bioavailability; CL/F, elimination clearance; V_C/F, apparent volume of distribution of central compartment; ka, first order absorption rate constant; Q_P1/F, flow rate to and from shallow peripheral compartment; V_P1/F, apparent volume of distribution of shallow peripheral compartment; Q_P2/F, flow rate to and from deep peripheral compartment; V_P2/F, apparent volume of distribution of deep peripheral compartment; θ_RBC/PL, red blood cells to plasma ratio; T₅₀, time at which of 50% post‐delivery effect; γ, post‐delivery effect shape parameter.

^a95% confidence interval denoted as 2.5–97.5 percentiles of the estimates from 500 iterations of a nonparametric bootstrap.

^bAll volumes and flow rates (clearance and flow rates to and from peripheral compartments) were allometrically scaled with total body weight centred on the median body weight (60 kg).

^cBSV and BOV were assumed as log‐normally distributed and are reported here as approximate CV%.

^*This parameter has the same value for both S and P.

Figure 2.

Observed day 7 concentrations in the Sudan and Mozambique sites for the pregnant and postpartum women. The boxplot summarises the observed concentrations, while the model predicted median concentrations are shown as a red line.