Selective delivery to the liver of antiviral nucleoside analogs coupled to a high molecular mass lactosaminated poly-L-lysine and administered to mice by intramuscular route.

In order to obtain hepatotropic conjugates of antiviral drugs suitable for intramuscular administration, three nucleoside analogs (adenine arabinoside monophosphate, ribavirin and azidothymidine) were coupled to a high molecular mass lactosaminated poly-L-lysine. The conjugates had a high molar ratio drug/conjugate and after intramuscular administration to mice, were selectively taken up by the liver and eliminated by the kidney only in minute quantities. The high molar ratio and low renal elimination are important properties not possessed by conjugates previously prepared by using a small molecular mass lactosaminated poly-L-lysine. The conjugate with adenine arabinoside monophosphate (ara-AMP) was found to be devoid of acute toxicity for mice and in spite of its high molecular dimension (Mn = ca. 72,500) did not induce antibodies in this animal after repeated intramuscular injections. This conjugate could have two advantages over a similar complex of ara-AMP with lactosaminated human albumin currently under clinical trials for the treatment of chronic type B hepatitis which must be injected intravenously: it might provide better patient compliance since it is injectable intramuscularly and could introduce larger amounts of ara-AMP into hepatocytes due to its higher drug/carrier molar ratio.