Population pharmacokinetics and pharmacodynamics of cysteamine in nephropathic cystinosis patients

Table 2 Population pharmacokinetic and pharmacodynamic parameters of WBC cystine levels and cysteamine standardized for a weight of 70 kg.

Parameters	Mean	RSE (%)
Structural pharmacokinetic model
ka (h^-1)	1.38	7
V/F (L/70 kg)	82.4	11
CL/F (L/h/70 kg)	42.3	8
Statistical pharmacokinetics model
ω _CL/F	0.28	10
σ	0.45	5
Structural pharmacodynamic model
Ro (nmol half-cystine/mg of protein)	1.59	9
K_out (h^-1)	20.2	33
E _max	3.82	7
EC ₅₀ (μmol/L)	12.5	15
Statistical pharmacodynamic model
ω _Ro	0.62	11
σ	0.49	5

Key: RSE%, relative standard error (standard error of estimate/estimate*100), Ka absorption rate constant, CL/F apparent elimination clearance, V/F apparent volume of distribution, Ro baseline (predose) cystine level, K_out first-order removal rate constant, Emax maximum stimulation of K_out, EC₅₀ concentration resulting in 50% of maximal response, σ residual variability estimates, ω interindividual variability estimates. The typical parameters refers to an adult patient weighing 70 kg according to an allometric model: [Typical value] = [Typical parameter] * (bodyweight/70)^PWR where PWR = 0.75 for CL and 1 for V.

ISSN: 1750-1172