Hepatocyte-targeted delivery of imiquimod reduces hepatitis B virus surface antigen
Nojoud A L Fayez 1 , Elham Rouhollahi 1 , Chun Yat Ong 1 , Jiamin Wu 1 , Anne Nguyen 1 , Roland Böttger 1 , Pieter R Cullis 2 , Dominik Witzigmann 2 , Shyh-Dar Li 3
Affiliations
Affiliations
1
Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
2
Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada; NanoMedicines Innovation Network (NMIN).
3
Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada; NanoMedicines Innovation Network (NMIN). Electronic address: [email protected].
PMID: 36058352 DOI: 10.1016/j.jconrel.2022.08.058
Abstract
Hepatitis B virus (HBV) can rapidly replicate in the hepatocytes after transmission, leading to chronic hepatitis, liver cirrhosis and eventually hepatocellular carcinoma. Interferon-α (IFN-α) is included in the standard treatment for chronic hepatitis B (CHB). However, this therapy causes serious side effects. Delivering IFN-α selectively to the liver may enhance its efficacy and safety. Imiquimod (IMQ), a Toll-Like Receptor (TLR) 7 agonist, stimulates the release of IFN-α that exhibits potent antiviral activity. However, the poor solubility and tissue selectivity of IMQ limits its clinical use. Here, we demonstrated the use of lipid-based nanoparticles (LNPs) to deliver IMQ and increase the production of IFN-α in the liver. We encapsulated IMQ in two liver-targeted LNP formulations: phospholipid-free small unilamellar vesicles (PFSUVs) and DSPG-liposomes targeting the hepatocytes and the Kupffer cells, respectively. In vitro drug release/retention, in vivo pharmacokinetics, intrahepatic distribution, IFN-α production, and suppression of serum HBV surface antigen (HBsAg) were evaluated and compared for these two formulations. PFSUVs provided >95% encapsulation efficiency for IMQ at a drug-to-lipid ratio (D/L) of 1/20 (w/w) and displayed stable drug retention in the presence of serum. DSPG-IMQ showed 79% encapsulation of IMQ at 1/20 (D/L) and exhibited ~30% burst release when incubated with serum. Within the liver, PFSUVs showed high selectivity for the hepatocytes while DSPG-liposomes targeted the Kupffer cells. Finally, in an experimental HBV mouse model, PFSUVs significantly reduced serum levels of HBsAg by 12-, 6.3- and 2.2-fold compared to the control, IFN-α, and DSPG-IMQ groups, respectively. The results suggest that the hepatocyte-targeted PFSUVs loaded with IMQ exhibit significant potential for enhancing therapy of CHB.
Keywords: Chronic hepatitis B (CHB); Hepatitis B surface antigen (HBsAg); Hepatitis B virus (HBV); Imiquimod (IMQ); Interferon-α (IFN-α); Phospholipid-free small unilamellar vesicles (PFSUVs).