Polysaccharide and monosaccharide guided liver delivery of Sorafenib Tosylate - A nano-strategic approach and comparative assessment of hepatospecificity.

Hepatospecific delivery by ligand based receptor targeting is an established strategy to augment therapy associated with liver diseases and disorders. Previously, we have investigated the effect of ligand headgroup on cellular uptake mediated by the asialoglycoprotein receptor by in silico and in vitro approach. In this paper, we report the design of agarose based liposomes for delivery to liver cancer cells and provide a proof of concept of the targeting efficiency against galactose liposomes using an in vivo approach. Sorafenib Tosylate loaded targeting liposomes were developed and optimized using factorial design. Comparative evaluation including cell cytotoxicity, pharmacokinetics and biodistribution and hepatospecific uptake was performed for both the liposomal systems. The formulations possessed a particle size of 150 - 180 nm and a zeta potential of 30 - 60 mV depending on the amount of ligand and drug loading, with more than 90% entrapment efficiency. A two-fold increase in cytotoxicity was observed with agarose-based liposomes as compared to galactose based liposomes. In vivo PK evaluation indicated a reduction in half life of drug when loaded in agarose ligand loaded system, probably due to greater uptake in the liver as evidenced in biodistribution study. Intrahepatic disposition revealed a higher PC/NPC uptake ratio with the targeted systems as compared to conventional liposomes, although the agarose-based system resulted in highest uptake ratio. A biocompatible platform for specific delivery of drugs to hepatocytes was established validating a rational approach to design liver targeting systems.

Polysaccharide conjugates surpass monosaccharide ligands in hepatospecific targeting - Synthesis and comparative in silico and in vitro assessment.

Ligands with the polysaccharide headgroups have been recently reported by our group to possess enhanced interaction with asialoglycoprotein receptor (ASGPR) in silico as compared to ligands having galactose moieties. This enhanced interaction is a result of the polymer's backbone support in anchoring the ligand in a specific orientation within the bilayer. In this paper, we have attempted to provide an in vitro proof of concept by performing a comparative evaluation of polysaccharide and monosaccharide-based ligands. Docking was performed to understand interaction with ASGPR in silico. Agarose and galactose conjugates with behenic acid were synthesized, purified, and characterized to yield biocompatible hepatospecific ligands which were incorporated into nanoliposomes. Cellular internalization of these targeted liposomes was studied using confocal microscopy and flow cytometry. The toxicity potential was assessed in vivo. Results indicated that the polysaccharide-based ligand increased cellular uptake due to better interaction with the receptor as compared to ligand bearing a single galactose group. In addition to developing novel liver targeting ligands, the study also established proof of concept that has been suggested by earlier in silico investigations. The approach can be used to design targeting ligands and develop formulations with improved targeting efficacy.