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.
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Description |
Parameter |
Unit | Estimates (RSE%) | | Base model | Empirical model
CL~GAa | Semiphysiological
Model CL~CrCLb |
| | Structural model | | | | | | | Clearance | | L/min | 0.49 | 0.119 (58) | 0.142 (44) | | Central volume | | L | 32.5 (16) | 33.1 (17) | 14.1 (25) | | Peripheral volume | | L | 12.8 (25) | 12.8 (27) | 17.1 | | Intercompartmental clearance | | L/min | 0.335 (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) |
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RSE: relative standard error; GA: gestational age (weeks). aEmpirical model: ; bsemiphysiological model: .
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