In vitro protein binding of cefonicid and cefuroxime in adult and neonatal sera.

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Benson JM, Boudinot FD, Pennell AT, Cunningham FE, DiPiro JT

In vitro protein binding of cefonicid and cefuroxime in adult and neonatal sera.

Antimicrob Agents Chemother. 1993 Jun;37(6):1343-7.

PubMed ID

8328784 [ View in PubMed

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Abstract

The levels of in vitro protein binding of cefonicid and cefuroxime in human adult and neonatal sera were compared. Binding parameters for each drug were determined within the concentration range of 25 to 3,000 micrograms/ml. Cefonicid exhibited concentration-dependent protein binding in both types of sera, with more extensive binding in adult serum at all concentrations. Two classes of binding sites were found: a high-affinity, saturable site and a low-affinity, nonspecific site. Cefuroxime also showed two-class, concentration-dependent protein binding in adult serum, but binding in neonatal serum was to a single class and was independent of drug concentration. Parameters for class 1 binding sites for cefonicid indicated one binding site per albumin molecule in both adult and neonatal sera, with association constants of 7.0 x 10(4) and 1.3 x 10(4) M-1, respectively. These parameters were also derived for cefuroxime in adult serum and were 0.15 and 7.1 x 10(4) M-1, respectively. In neonatal serum, the combined value (number of binding sites per molecule x equilibrium association constant) was similar to combined values calculated for class 2 binding sites for cefuroxime in adult serum and for cefonicid in neonatal serum (287 versus 195 and 261 M-1, respectively). Cephalosporins have been shown to compete with bilirubin for albumin binding sites. Lower levels of protein binding of cefuroxime in the therapeutic range may mean a lower potential for drug displacement of bilirubin in neonates, on the basis of these results. It may be prudent to select less highly protein-bound agents when treating neonatal infections.

DrugBank Data that Cites this Article

Drug Carriers

Drug	Carrier	Kind	Organism	Pharmacological Action	Actions
Cefonicid	Serum albumin	Protein	Humans	No	Other/unknown	Details