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Table 3 Final model parameters describing joint fixed plasma and hair pharmacokinetics of atazanavir

From: A population pharmacokinetic model is beneficial in quantifying hair concentrations of ritonavir-boosted atazanavir: a study of HIV-infected Zimbabwean adolescents

Parameter

Population mean (SE as %)

1000 samples bootstrap medians (90% CI)

Variability (SE as %)

1000 samples bootstrap medians (90% CI)

k12 (litres hour− 1)

0.44 fixed

0.44 fixed

0.45 fixed

0.44 fixed

CL/F (litres hour−1)

10 fixed

10 fixed

1.04 (99)

0.97 (0.50–1.98)

Vc (litres)

63.4 fixed

63.4 fixed

0.50 fixed

0.50 fixed

Frac

0.16 (16)

0.15 (0.06 to 0.26)

  

Vh (litres)

1 fixed

1 fixed

  

Occasion (Follow-up)_ Frac

*

*

  

Occasion (Enrolment)_ Frac

−0.30 (23)

−0.27 (−0.50 to −0.07)

  

Adherence score_ Frac

0.02 (18)

0.015 (0.004 to 0.017)

  

Body Mass Index-for-age (Normal)_ Frac

*

*

  

Body Mass Index-for-age (Thin)_ Frac

0.54 (22)

0.49 (0.06 to 0.74)

  

Body Mass Index-for-age (Overweight)_ Frac

−0.21 (121)

− 0.15 (− 0.26 to − 0.05)

  

Guardian (Grandparent)_ Frac

*

*

  

Guardian (Parent)_ Frac

0.53 (56)

0.55 (0.03 to 2.58)

  

Guardian (Uncle/Aunt)_ Frac

0.12 (177)

0.17 (0.05 to 1.60)

  

Guardian (Sibling)_ Frac

−0.54 (35)

−0.60 (− 0.92 to − 0.27)

  

ɛADD

0.30 (1)

0.29 (0.14 to 0.44)

  

ɛPROP

0.50 (2)

0.50 (0.39 to 0.61)

  

σ

1

1

  
  1. k12: Absorption rate constant; CL/F: apparent drug clearance; Vc and Vh: apparent volume of distribution in the central and hair compartments, respectively; Frac amount of drug cleared into the hair as a proportion of the amount of drug in plasma at steady-state troughs; FACTOR_ Frac: effect of covariate on Frac; ɛADD and ɛPROP: additive and proportional error terms, respectively; σ: residual error; SE: standard error. *: reference group