Protein binding and bilirubin displacing properties of bumetanide and furosemide.

We evaluated the protein binding and comparative bilirubin displacing properties of bumetanide and furosemide in pooled adult and cord serum by ultrafiltration (UF), difference spectra (DS), and Sephadex Gel-25 (SG-25) filtration. By UF, bumetanide was found to be highly protein bound (96.7 per cent), similar to published data on furosemide (97.

Metabolism of theophylline to caffeine in human fetal liver.

Caffeine (1,3,7-trimethylxanthine) is a biotransformation product of theophylline (1,3-dimethylxanthine) in the human fetus. Liver explants, obtained from human fetuses with gestational ages of 12 to 20 weeks, were incubated with theophylline and produced caffeine and, in lesser amounts, 1,3-dimethyluric acid and 3-methylxanthine. These findings suggest that the predominant pathway in theophylline metabolism in the fetus and newborn infant is the methylation reaction producing caffeine.