D‐PENICILLAMINE, A NON‐BILIRUBIN‐DISPLACING DRUG IN NEONATAL JAUNDICE

Abstract
D-penicillamine, a drug used clinically for the treatment of neonatal hyperbilirubinemia, was tested for interference with the binding of bilirubin to human serum albumin by 3 methods: the peroxidase technique, investigating the effect of D-penicillamine on the equilibrium concentration of unbound bilirubin in a solution containing a molar excess of albumin; the MADDS method, measuring the concentration of vacant bilirubin binding site on albumin in a solution of pure albumin, or infant blood serum, with added D-penicillamine; and injection of D-penicillamine into Gunn rats and determination of any decrease of plasma bilirubin which would be caused by displacement of the pigment. Results were negative in all cases. Quantitatively, the doses of D-penicillamine used clinically cannot displace bilirubin from its binding to albumin. The ameliorating effect on hyperbilirubinemia in the newborn must be due to some other mechanism.