ISSN:
1432-1041
Keywords:
naloxone
;
plasma protein binding
;
albumin
;
alpha1-acid glycoprotein
;
beta-lipoprotein
;
adult plasma
;
foetal/umbilical plasma
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Medicine
Notes:
Summary Binding of naloxone hydrochloride was determined at 37°C, by equilibrium dialysis against 0.067 M phosphate buffer, pH 7.4, in plasma obtained from 18 healthy adults, and 18 samples of umbilical cord venous (foetal) plasma. The percentage free fraction (% free) in plasma was independent of naloxone concentration (9 ng/ml to 2.5 µg/ml). Percent free naloxone in adult (x=54.0) was lower (p〈0.01) than in foetal (x=61.5) plasma. In buffered solutions of purified HSA, %free naloxone (x=68.7) was independent of HSA concentration over the range 3.0 g/dl to 5.5 g/dl. Adult plasma concentrations of α1-acid glycoprotein (α1-AGP) and β-lipoprotein were higher (p〈0.01) than foetal concentrations. Furthermore %free naloxone in foetal plasma decreased with the in-vitro addition of purified α1-AGP. It is suggested that qualitative differences in adult and foetal albumin and quantitative differences in plasma levels of α1-AGP and perhaps β-lipoprotein are responsible for naloxone plasma binding differences between adults and the newborn.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00549595
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