Table 2.

Population pharmacokinetic estimates of vancomycin of maturation model.

Parameters	Model I	Model II	Model III	Model IV
Model description	CLp×(WT/WTmedian) k×MF
MF	1	$\text{MF}=\frac{1}{1+{\left(\frac{\text{Age}}{\text{T}{\text{M}}_{50}}\right)}^{\text{Hill}}}$	1	1
k	/	0.75	${\theta }_0-\frac{{\text{k}}_{max}\times \text{W}{\text{T}}^{\text{Hill}}}{{{\text{k}}_{50}}^{\text{Hill}}+\text{W}{\text{T}}^{\text{Hill}}}$	${\theta }_0-\frac{{\text{k}}_{max}\times \text{Ag}{\text{e}}^{\text{Hill}}}{{{\text{k}}_{50}}^{\text{Hill}}+{\text{Age}}^{\text{Hill}}}$
Objective function value	855.1	852.2	871.1	871.1
Akaike information criteria	867.1	864.2	895.9	895.9
Bayesian information criteria	885.7	882.8	855.1	855.1
Condition number	4.54	23082	510000	641732
CLp (RSE%)	0.319 (5.1%)	0.911 (235%)	0.319 (5.1%)	0.319 (5.1%)
k (RSE%)	1.57 (10.9%)	/	/	/
TM50 (RSE%)	/	46.9 (102%)	/	/
Hill (RSE%)	/	4.45 (105%)	23.6 (17.2%)	60.7 (23.4%)
θ0 (RSE%)	/	/	1.57 (10.9%)	1.57 (10.9%)
kmax (RSE%)	/	/	1.08 (25%)	1.08 (25%)
k50 (RSE%)	/	/	12.7 (53.1%)	62.3 (22%)
INTER-INDIVIDUAL VARIABILITY
CL (%CV)	38.6% (28.9%)	39.2% (26.4%)	39.2% (26.4%)	39.2% (26.4%)
RESIDUAL VARIABILITY
Proportional (%CV)	37.9% (19.2%)	37.9% (20.4%)	37.9% (20.4%)	37.9% (20.4%)

CL_p typical value of apparent clearance (L/h), Hill coefficient determining the steepness of the sigmoidal decline, k the exponents for body weight, k_max, maximum decrease, k₅₀ the body weight or age at which there is a 50 % decrease in the k_max, MF maturation function, RSE: relative standard error, TM₅₀ the age at which clearance maturation reaches 50% of that of adults, θ₀ the exponent at a theoretical WT of 0 kg or age at birth.