Table 2.

Ticarcillin population pharmacokinetic equations and parameter estimates

Equations
$\mathit{CL}={\theta }_{\mathit{CL}}*{\left(\frac{{\mathit{WT}}_i}{70}\right)}^{0.75}*\left(\frac{{{\mathit{PMA}}_i}^{\mathit{\text{Hill}}}}{{{\mathit{TM}}_{50}}^{\mathit{\text{Hill}}}+{{\mathit{PMA}}_i}^{\mathit{\text{Hill}}}}\right)*{\left(\frac{\mathit{SCR}}{0.5}\right)}^{{\theta }_{\mathit{CL}\sim \mathit{SCR}}}$
$V={\theta }_V*{\left(\frac{{\mathit{WT}}_i}{70}\right)}^1$
Parameter	Estimate	RSE (%)	2.5th percentile	Bootstrapa median	97.5th percentile
Structural model
θCL (L/h)	11.0	4.1	10.1	11.0	11.8
θV (L)	32.3	4.5	29.1	32.3	35.0
θCL~SCR	−0.257	35.5	−0.426	−0.265	−0.072
TM50 (weeks)	47.7 FIX	‐	‐	‐	‐
Hill	3.4 FIX	‐	‐	‐	‐
Between‐subject variability
CL (%CV)	11.5	51.9	2.6	10.8	16.7
V (%CV)	0 FIX	‐	‐	‐	‐
Residual error
Proportional error (%)	21.0	26.0	14.9	20.7	25.6

CL, clearance; CV, coefficient of variation; Hill, Hill coefficient; RSE, relative standard error; SCR, serum creatinine; TM₅₀, age (weeks) when 50% adult clearance is reached; V, volume of distribution; V_70KG, volume of distribution (L) scaled to 70 kg; PNA, postnatal age.

^a1000 bootstrap runs were performed.