Carbohydrate mediated drug delivery: synthesis and characterization of new lipid-conjugates

A new synthetic methodology for cationic glycolipids using p-aminophenyl-α-D-mannopyranoside (PAPM) and p-aminophenyl-α-D-galactopyranoside (PAPG) with spacer in between the quaternary nitrogen atom and the sugar unit is developed. In addition, a new class of neutral glycolipid conjugates, such as PAPM-lipids or PAPG-lipids conjugates was also synthesized for targeting drugs to receptors. The precipitation-inhibition assay showed that conjugate of PAPM inhibited the concanavalin A and invertase aggregation. This binding inhibition study of a synthesized compound suggests that conjugates of PAPM can be potentially used to target mannose receptors. In addition, a higher transfection was obtained by mixing PAPM with pSV-β-gal reporter gene and incubating with mannose binding protein/receptor expressing A549 cells. The coexistence of both mannose group and a net positive charge may result in improved transfection efficiency in cells expressing mannose binding proteins/receptors.