PREPARATION AND LECTIN-BINDING CHARACTERISTICS OF N-STEARYL LACTOBIONAMIDE LIPOSOMES

In order to target liposomes containing therapeutic contents to specif ic cells possessing galactose receptors, we synthesized the neoglycoli pid, N-stearyl lactobionamide (N-SLBA), via the lactone form of lactob ionic acid. Liposomes containing 0, 7.6, 10 and 15 mol% of N-SLBA, res pectively, were used to study the impact of liposomal surface galactos e density on the lectin-binding characteristics. As a lectin, Ricinus communis agglutinin (RCA) was used. Aggregation of N-SLBA liposomes wa s promoted with higher concentration of RCA, indicating that the galac tose moieties on N-SLBA liposomes are accessible to lectin binding sit es. RCA binding rates of liposomes increased with liposomal N-SLBA con tents. No binding was observed between RCA and ungalactosylated contro l liposomes. The extent of lectin binding was also dependent on the li posomal galactose density. Rosenthal plots quantitatively revealed tha t the association constant (K-a) increased in proportion to N-SLBA con tents of liposomes. These results suggest that the rate and extent of liposomal drug delivery to a target site with galactose receptors migh t be controlled by adjusting the N-SLBA contents of liposomes.