Development of mannosylated liposomes using synthesized N-octadecyl-D-mannopyranosylamine to enhance gastrointestinal permeability for protein delivery.

The lysozyme (LZ)-entrapped mannosylated liposomes were prepared in this study by the use of N-octadecyl-D-mannopyranosylamine (SAMAN), which had been synthesized in-house and confirmed by characterization with FTIR and NMR. The reactant residues of synthesized SAMAN were found to be less than 1%. The mean sizes, zeta potentials, drug entrapment efficiencies, and loading capacities of all liposomal formulations were in the ranges of 234.7 to 431.0 nm, -10.97 to -25.80 mV, 7.52 to 14.10%, and 1.44 to 2.77%, respectively. The permeability of mannosylated LZ liposomes across Caco-2 cell monolayers was significantly enhanced to about 2.5- and 7-folds over those of conventional liposomes and solution, respectively, which might be due to the role of mannose receptor or mannose-binding protein on the intestinal enterocytes.