Table 3 Pharmacokinetic model parameters for (S)-(nor)ketamine. Population parameters for (S)-ketamine were estimated by Fanta et al. [27]. Population parameters for Vd and CL were scaled allometrically: θ*(weight/70)exponent, where the scaling exponent is 1 for Vd and 0.75 for CL. Shrinkage (%) of estimated IIV parameters is reported in brackets

From: Predictive performance of parent-metabolite population pharmacokinetic models of (S)-ketamine in healthy volunteers

  Estimate RSE%
(S)-ketamine
Population parameters (θ)
Vd 133 -
CL 95.2 -
Vp1 187 -
Q1 23.2 -
Vp2 98.8 -
Q2 157 -
Inter-individual variability (ω2)
Vd 0.084 [7.1] 28.4
CL 0.026 [13.2] 21.9
Covariance 0.023 37.8
Residual variability (σ2)
Proportional error 0.056 10.3
(S)-norketamine
Population parameters (θ)
Vd 98.6 3.77
CL 57.7 5.7
Vp1 160 17.6
Q1 42.8 7.51
Inter-individual variability (ω2)
Vd 0.040 [22.9] 29
CL 0.103 [2.8] 22
Covariance 0.044 30.3
Residual variability (σ2)
Proportional error 0.020 14.2
  1. The condition numbers of the (S)-ketamine IIV re-estimation and (S)-norketamine model redevelopment were 4.44 and 21.45 respectively
  2. RSE relative standard error, Vd distribution volume, CL clearance, Vp peripheral compartment, Q inter-compartmental clearance