Use of D-Penicillamine in the Neonatal Hyperbilirubinemias

It appears that bilirubin IXᾰ has unique structural properties which might have been predicted on the basis of modern concepts of organic chemistry but whose biological implications certainly were not fully appreciated [1]. The initial breakdown product of haemoglobin is UCB (unconjegated or indirect bilirubin) which is insoluble in water but soluble in lipids. This process is catalyzed by an important rate limiting enzyme, heme oxygenase (HO). UCB is carried in the blood bound to albumin. It is taken up by the liver and conjugated by the enzyme uridine 5’-diphospho-(UDP)glucuronyltransferase to conjugated bilirubin (direct bilirubin) which is water soluble and excreted in bile into the gut and is detectable in urine when blood levels rise [2].