Sorafenib-Entrapped, Self-Assembled Pullulan-Stearic Acid Biopolymer-Derived Drug Delivery System to PLC/PRF/5 Hepatocellular Carcinoma Model.

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.

Folic acid conjugation improves the bioavailability and chemosensitizing efficacy of curcumin-encapsulated PLGA-PEG nanoparticles towards paclitaxel chemotherapy.

Nanoencapsulation has emerged as a novel strategy to enhance the pharmacokinetic and therapeutic potential of conventional drugs. Recent studies from our lab have established the efficacy of curcumin in sensitizing cervical cancer cells and breast cancer cells towards paclitaxel and 5-FU chemotherapy respectively. Factors that hinder the clinical use of curcumin as a sensitizer or therapeutic agent include its poor bioavailability and retention time. Earlier reports of improvement in bioavailability and retention of drugs upon nanoencapsulation have motivated us in developing various nanoformulations of curcumin, which were found to exhibit significant enhancement in bioavailability and retention time as assessed by our previous in vitro studies. Among the various formulations tested, curcumin-entrapped in PLGA-PEG nanoparticles conjugated to folic acid (PPF-curcumin) displayed maximum cell death. In the present study, we have demonstrated the efficacy of this formulation in augmenting the bioavailability and retention time of curcumin, in vivo, in Swiss albino mice. Further, the acute and chronic toxicity studies proved that the formulation is pharmacologically safe. We have also evaluated its potential in chemosensitizing cervical cancer cells to paclitaxel and have verified the results using cervical cancer xenograft model in NOD-SCID mice. Folic acid conjugation significantly enhanced the efficacy of curcumin in down-regulating various survival signals induced by paclitaxel in cervical cancer cells and have considerably improved its potential in inhibiting the tumor growth of cervical cancer xenografts. The non-toxic nature coupled with improved chemosensitization potential makes PPF-curcumin a promising candidate formulation for clinical trials.