BioMed Research International / 2014 / Article / Tab 2

Research Article

Semiphysiological versus Empirical Modelling of the Population Pharmacokinetics of Free and Total Cefazolin during Pregnancy

Table 2

Parameter estimates of the base and final population PK models (empirical and semiphysiological) for cefazolin.

Description Parameter UnitEstimates (RSE%)
Base modelEmpirical model
CL~GAa
Semiphysiological
Model CL~CrCLb

Structural model
 Clearance L/min0.49 0.119 (58)0.142 (44)
 Central volume L32.5 (16)33.1 (17)14.1 (25)
 Peripheral volume L12.8 (25)12.8 (27)17.1
 Intercompartmental clearance L/min0.335 (21)0.326 (25)0.436 (10)
 Free fraction 0.289 0.286 0.291 (9)
 Gestation effect on clearance 0.217 (16)0.212 (38)
Between subject variability
 Clearance CV%22.1 (25)19.9 (24)10.4 (70)
 Central volume CV%49.1 (22)47.6 (21)101.5 (21)
 Peripheral volume CV%32.7 (41)34.2 (41)68 (26)
 Free fraction CV%18.9 (36)17.5 (37)19.1 (38)
Residual unexplained variability variances
 Proportional, free concentration 0.0162 0.0158 (11)0.0153
 Additive, free concentration 0.176 (34)0.229 (42)0.217 (36)
 Proportional, total concentration 0.0348 0.0328 (10)0.0328 (9)
 Additive, total concentration 0.662 (48)0.842 (46)0.681 (25)

RSE: relative standard error; GA: gestational age (weeks). aEmpirical model: ; bsemiphysiological model: .

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