Pyridine-2,6-dicarboxaldehyde-Enabled N-Terminal In Situ Growth of Polymer-Interferon α Conjugates with Significantly Improved Pharmacokinetics and In Vivo Bioactivity

Mechanism of interferon alpha therapy for chronic hepatitis B and potential approaches to improve its therapeutic efficacy

Hepatitis B virus (HBV) chronically infects 296 million people worldwide and causes more than 820,000 deaths annually due to cirrhosis and hepatocellular carcinoma. Current standard-of-care medications for chronic hepatitis B (CHB) include nucleos(t)ide analogue (NA) viral DNA polymerase inhibitors and pegylated interferon alpha (PEG-IFN-α). NAs can efficiently suppress viral replication and improve liver pathology, but not eliminate or inactivate HBV covalently closed circular DNA (cccDNA). CCC DNA is the most stable HBV replication intermediate that exists as a minichromosome in the nucleus of infected hepatocyte to transcribe viral RNA and support viral protein translation and genome replication. Consequentially, a finite duration of NA therapy rarely achieves a sustained off-treatment suppression of viral replication and life-long NA treatment is most likely required. On the contrary, PEG-IFN-α has the benefit of finite treatment duration and achieves HBsAg seroclearance, the indication of durable immune control of HBV replication and functional cure of CHB, in approximately 5% of treated patients. However, the low antiviral efficacy and poor tolerability limit its use. Understanding how IFN-α suppresses HBV replication and regulates antiviral immune responses will help rational optimization of IFN therapy and development of novel immune modulators to improve the rate of functional cure. This review article highlights mechanistic insight on IFN control of HBV infection and recent progress in development of novel IFN regimens, small molecule IFN mimetics and combination therapy of PEG-IFN-α with new direct-acting antivirals and therapeutic vaccines to facilitate the functional cure of CHB.

Microparticles of Sericin-Dextran Conjugate for Improving the Solubility of Antiviral Drug

A novel sericin-dextran conjugate (SDC) and self-assembled microparticles has been prepared for improving solubility of atazanavir. Microparticles of SDC were assembled by the reprecipitation method. The size and morphology of SDC microparticles could be adjusted by the concentration and solvents. Low concentration was conducive to the preparation of microspheres. Heterogeneous microspheres could be prepared in ethanol with the range of 85-390 nm, and hollow mesoporous microspheres in propanol with an average particle size of 2.5-22 µm. The aqueous solubility of atazanavir was improved to 2.22 mg/mL in buffer solutions at pH 2.0 and 1.65 mg/mL at pH 7.4 by SDC microspheres. In vitro release of atazanavir from hollow microspheres of SDC exhibited a slower release, had the lowest linear cumulative release in basic buffer (pH 8.0), and the most rapid double exponential diphase kinetic cumulative release in acid buffer (pH 2.0).

N-Terminal Lysozyme Conjugation to a Cationic Polymer Enhances Antimicrobial Activity and Overcomes Antimicrobial Resistance

Microbial resistance to antibiotics is one of the greatest global healthcare challenges. There is an urgent need to develop effective strategies to overcome antimicrobial resistance. We, herein, report photoinduced in situ growth of a cationic polymer from the N-terminus of lysozyme. The attachment of the cationic polymer improves the proteolytic and thermal stability of lysozyme. Notably, the conjugate can efficiently overcome lysozyme resistance in Gram-positive bacteria and antibiotics-resistance in Gram-negative bacteria, which may be ascribed to the synergistic interactions of lysozyme and the cationic polymer with the bacteria to disrupt their cell membranes. In a rat periodontitis model, the lysozyme-polymer conjugate not only greatly outperforms lysozyme in therapeutic efficacy but also is superior to minocycline hydrochloride, which is the gold standard for periodontitis therapy. These findings may provide an efficient strategy to dramatically enhance the antimicrobial activities of lysozyme and pave a way to overcome antimicrobial resistance.

Lipid-Based Ionic-Liquid-Mediated Nanodispersions as Biocompatible Carriers for the Enhanced Transdermal Delivery of a Peptide Drug

Lipid-based biocompatible ionic liquids (LBILs) have attracted attention as carriers in transdermal drug delivery systems (TDDSs) because of their lipophilic character. In this study, we report the formulation of a peptide-LBIL complex microencapsulated in an oil phase as a potential carrier for the transdermal delivery of leuprolide acetate as a model hydrophilic peptide. The peptide-LBIL complexes were prepared via a water-in-oil emulsion composed of 1,2-dimyristoyl-sn-glycerol-3-ethyl-phosphatidylcholine (EDMPC), a fatty acid (stearic, oleic, and linoleic acid)-based LBIL, and cyclohexane followed by freeze-drying to remove the water and cyclohexane. Then, the peptide-LBIL complexes were nanodispersed and stabilized in isopropyl myristate (IPM) using sorbitol laurate (Span-20). Ionic-liquid-in-oil nanodispersions (IL/O-NDs) were prepared with varying weight ratios of LBILs and Span-20 as the surfactant and the cosurfactant, respectively. Keeping the overall surfactant constant at 10 wt % in IPM, a 5:5 wt % ratio of surfactant (IL) and cosurfactant (Span-20) in the IL/O-NDs significantly (p < 0.0001) increased the physiochemical stability, drug-loading capacity, and drug encapsulation efficiency. The in vitro and in vivo peptide delivery across the skin was increased significantly (p < 0.0001) using IL/O-NDs, compared with non-IL-treated groups. Of all of the LBIL-based formulations, [EDMPC][Linoleate]/O-ND was considered the most preferable for a TDDS based on the pharmacokinetic parameters. The transdermal delivery flux with [EDMPC][Linoleate]/O-ND was increased 65-fold compared with the aqueous delivery vehicle. The IL/O-NDs were able to deform the lipid and protein arrangements of the skin layers to enhance the transdermal permeation of the peptide. In vitro and in vivo cytotoxicity studies of the IL/O-NDs revealed the biocompatibility of the LBIL-based formulations. These results indicated that IL/O-NDs are promising biocompatible carriers for lipid-peptide TDDSs.

2,6-Bis((benzoyl-R)amino)pyridine (R = H, 4-Me, and 4-NMe2) Derivatives for the Removal of Cu(II), Ni(II), Co(II), and Zn(II) Ions from Aqueous Solutions in Classic Solvent Extraction and a Membrane Extraction

In this paper, the application of new substituted 2,6-bis((benzoyl-R)amino)pyridine (R = H, 4-Me, and 4-NMe₂) derivatives for the recovery of copper(II), nickel(II), cobalt(II), and zinc(II) ions from aqueous solutions was described. The structures of the synthesized compounds were confirmed by nuclear magnetic resonance spectroscopy (NMR), electrospray ionization high-resolution mass spectrometry (ESI HRMS), and tandem mass spectrometry methods (HCD MS/MS). Three different derivatives of 2,6-bis((benzoyl-R)amino)pyridine were used as carriers in membrane processes and as extractants in classic solvent extraction. In each case, the single derivative recovery was carried out on a model solution that contained only one type of metal ions. Spectrophotometry studies were performed to determine the stability constants of the complexes formed by the synthesized species with analyzed metals ions. The results obtained indicate that the synthesized compounds form stable complexes with Cu(II), Ni(II), Co(II), and Zn(II) ions and can be used in both types of studied recovery processes. However, the effectiveness of the synthesized compounds in the recovery of metal ions depends both on the structure of compounds and properties of metals as well as on their concentration.