Selective penetration and pharmacological activity of lactosaminated albumin conjugates of adenine arabinoside 5-monophosphate (ara-AMP) in mouse liver.

With the aim of improving the chemotherapeutic index of adenine arabinoside 5-monophosphate (ara-AMP) in the treatment of chronic hepatitis B, this drug was conjugated with lactosaminated serum albumin (L-SA), a neoglycoprotein which only enters into hepatocytes where it is digested in lysosomes. In mice, the L-[3H]SA-ara-AMP conjugates, intravenously injected, selectively penetrated the liver, only small quantities were taken up by cells of spleen, bone marrow, intestine, and brain. After administration of the conjugate to mice with Ectromelia virus hepatitis, ara-AMP was selectively concentrated in liver in a pharmacologically active form. If L-SA-ara-AMP conjugates behave in man as in mouse, their administration to patients with chronic hepatitis B should result in a selective concentration of ara-AMP in liver with a more efficient inhibition of virus replication accompanied by lower toxicity for other tissues.