Plasma protein binding of dicloxacillin: effects of age and diseases.

Dicloxacillin protein binding was investigated in sera from 10 umbilical cords, 20 children (aged between 2 and 21 months) and in the plasma from 8 healthy young subjects, 7 healthy elderlies, 10 patients with liver cirrhosis, 10 patients with renal failure (glomerulonephritis) and 10 chronic uremics maintained on hemodialysis. The percentage unbound fraction (mean +/- SD) of dicloxacillin was 7.3 +/- 0.8 (healthy subjects), 9.8 +/- 0.6 (umbilical cords), 7.4 +/- 2.8 (children), 8.8 +/- 1.0 (elderlies), 11.8 +/- 6.3 (cirrhosis), 10.5 +/- 2.0 (renal failure), 12.7 +/- 2.0 (before hemodialysis) and 11.7 +/- 2.1 (after hemodialysis). Healthy subjects were different from all the groups (0.001 greater than p greater than 0.05) except children (p greater than 0.5) (Student's t-test). Human isolated albumin (45 g/l) bound dicloxacillin at the same degree as the plasma of healthy subjects. The kinetics of dicloxacillin protein binding was studied in three umbilical cord serum, three adult plasma specimens and in human serum albumin. The number of binding sites (n) and the association constant (k) were estimated by Lineweaver-Burk double reciprocal plot.(ABSTRACT TRUNCATED AT 250 WORDS)