Sugar-coated liposomes: a novel delivery system for increased drug efficacy and reduced drug toxicity.

The uptake of glycoside-bearing liposomes by macrophages has been studied in vitro. Since the uptake was found to be specific for the end sugar attached to the glycoside, the possibility is raised that glycoside-bearing liposomes might be used in vivo as systems to deliver drugs to macrophages. Using the antileishmanial drug urea stibamine, these delivery systems have been tested in vivo against model leishmaniasis. The results indicate that the drug encapsulated in sugar-coated liposomes is much more potent in comparison with normal liposome-encapsulated drug or to the free drug. Mannose-grafted liposomes are more efficient in transportation of drugs compared with those bearing glucose. Toxicity studies involving blood parameters, histological staining of tissues and specific enzyme activities related to liver function, show no apparent toxicity with the drugs. Hence, drug encapsulated sugar-coated liposomes may have possible applications to humans.