Galactosylated bilosomes for liver-targeted delivery of ledipasvir: optimization, conjugate synthesis, and cellular evaluation

Ledipasvir is one of the direct-acting antiviral agents used for treating hepatitis C virus (HCV) infection. To achieve dose reduction and cost-effective therapy, this study aimed to enhance the interaction of ledipasvir with HCV-infected hepatocytes through the development of cationic bilosomes (CBs) and galactosylated bilosomes (GBs). These delivery systems were designed to promote hepatocellular targeting via the asialoglycoprotein receptors (ASGPRs). Eight bilosomal formulations were developed by the ethanol injection method following a 2³ full factorial design, and numerical optimization using Design Expert® software identified the optimized formulation. In parallel, galactosylated stearylamine (GSA) was synthesized through conjugation of stearylamine (SA) with lactobionic acid (LB). The successful synthesis of GSA was verified through FTIR and 1H NMR spectroscopic analyses. SA and GSA were subsequently incorporated into the optimized bilosomes to obtain CBs and GBs, respectively. The prepared systems were evaluated for particle size, polydispersity index, entrapment efficiency, and zeta potential, and their morphology was identified using transmission electron microscopy. Following 8-h incubation with HepG2 cells, CBs and GBs achieved significantly higher cumulative cellular uptake of ledipasvir (31.79% ± 3.11% and 20.62% ± 2.12%, respectively) compared to the ledipasvir free dispersion (11.02% ± 3.02%). These findings highlight CBs and GBs as promising nanocarriers for targeted delivery of ledipasvir to hepatocytes.