Abstract
PURPOSE: This study aimed to design a prototypic drug delivery system (DDS) made of an amphiphilic, pullulan (Pull)-derived biodegradable polymer for targeting the asialoglycoprotein receptor (ASGPR) overexpressed in HCC. Stearic acid (SA) was conjugated to increase the hydrophobicity of pullulan (Pull-SA). METHODS: Pullulan (Pull) was linked to stearic acid (SA) after functional group modifications via EDC/NHS chemistry and characterized. Sorafenib tosylate (SRFT) was entrapped in pullulan-stearic acid nanoparticles (Pull-SA-SRFT) and its particle size, zeta potential, entrapment efficiency (EE), loading capacity (LC), and release efficiency was measured. The competence of Pull-SA-SRFT over SRFT in vitro was assessed using the ASGPR over-expressing PLC/PRF/5 hepatocellular carcinoma (HCC) cell line. This was done by studying cytotoxicity by MTT assay and chromosome condensation assay, early apoptosis by annexin-Pi staining, and late apoptosis by live-dead assay. The cellular uptake study was performed by incorporating coumarin-6 (C6) fluorophore in place of SRFT in Pull-SA conjugates. A biodistribution study was conducted in Swiss-albino mice to assess the biocompatibility and targeting properties of SRFT and Pull-SA-SRFT to the liver and other organs at 1, 6, 24, and 48 h. RESULTS: The characterization studies of the copolymer confirmed the successful conjugation of Pull-SA. The self-assembled amphiphilic nanocarrier could proficiently entrap the hydrophobic drug SRFT to obtain an entrapment efficiency of 95.6% (Pull-SA-SRFT). Characterization of the synthesized nanoparticles exhibited highly desirable nanoparticle characteristics. In vitro, apoptotic studies urged that Pull-SA-SRFT nanoparticle was delivered more efficiently to HCC than SRFT. The cellular uptake study performed, gave propitious results in 4 hrs. The biodistribution study conducted in immunocompetent mice suggested that Pull-SA-SRFT was delivered more than SRFT to the liver when compared to other organs, and that the system was biocompatible. CONCLUSION: Pull-SA-SRFT is a promisingly safe, biodegradable, cell-specific nanocarrier and a potential candidate to target hydrophobic drugs to HCC.