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Updated: May 20, 2026

Comprehensive Evaluation of the Effectiveness and Safety of Placenta-Targeted Drug Delivery Using Three Complementary Methods
Published on: September 10, 2018
Cefazolin plasma protein binding and its covariates in neonates
A Smits1, A Kulo, R Verbesselt
1Neonatal Intensive Care Unit, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium. anne.smits@uzleuven.be
Neonatal cefazolin (CFZ) protein binding is higher than in adults and varies with albumin levels, bilirubin, and postmenstrual age (PMA). Understanding this binding is crucial for optimizing CFZ dosing in newborns.
Area of Science:
- Pharmacology
- Neonatal Medicine
- Drug Metabolism
Background:
- Cefazolin (CFZ) exhibits high, saturable protein binding to human serum albumin (HSA) in adults.
- Limited data exists on CFZ protein binding characteristics in neonatal populations.
Purpose of the Study:
- To characterize cefazolin (CFZ) protein binding in neonates.
- To identify covariates influencing unbound CFZ fraction in this population.
Main Methods:
- Intravenous CFZ (50 mg/kg) administered to neonates prior to surgery.
- Measurement of total and unbound CFZ plasma concentrations at multiple time points (0.5, 2, 4, 8 hours).
- Linear and multiple regression analyses to identify binding covariates; Wilcoxon signed-rank test for paired analysis.
Main Results:
- Median unbound CFZ fraction was 0.39, significantly higher than in adults.
- Unbound fraction correlated with total CFZ concentration (R²=0.39).
- Albuminaemia, total CFZ concentration, indirect bilirubinaemia, and postmenstrual age (PMA) explained 49.6% of the variability in unbound CFZ fraction.
Conclusions:
- Neonatal CFZ protein binding is saturable and higher than in adults.
- Key factors influencing neonatal CFZ binding include albuminaemia, total CFZ concentration, indirect bilirubinaemia, and PMA.
- Protein binding assessment is recommended for neonatal pharmacokinetic evaluations of highly protein-bound drugs to optimize dosing.
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