Antiviral role of nanomaterials: a material scientist's perspective

Graphene-based materials as nanoplatforms for antiviral therapy and prophylaxis

INTRODUCTION

The dramatic effects caused by viral diseases have prompted the search for effective therapeutic and preventive agents. In this context, 2D graphene-based nanomaterials (GBNs) have shown great potential for antiviral therapy, enabling the functionalization and/or decoration with biomolecules, metals and polymers, able to improve their interaction with viral nanoparticles.

AREAS COVERED

This review summarizes the most recent advances of the antiviral research related to 2D GBNs, based on their antiviral mechanism of action. Their ability to inactivate viruses by inhibiting the entry inside cells, or through drug/gene delivery, or by stimulating the host immune response are here discussed. As reported, biological studies performed in vitro and/or in vivo allowed to demonstrate the antiviral activity of the developed GBNs, at different stages of the virus life cycle and the evaluation of their long-term toxicity. Other mechanisms closely related to the physicochemical properties of GBNs are also reported, demonstrating the potential of these materials for antiviral prophylaxis.

EXPERT OPINION

GBNs represent valuable tools to fight emerging or reemerging viral infections. However, their translation into the clinic requires standardized scale-up procedures leading to the reliable and reproducible synthesis of these nanomaterials with suitable physicochemical properties, as well as more in-depth pharmacological and toxicological investigations. We believe that multidisciplinary approaches will give valuable solutions to overcome the encountered limitations in the application of GBNs in biomedical and clinical field.

Engineering a novel water-in-oil biocompatible microemulsion system for the ocular delivery of dexamethasone sodium phosphate in the treatment of acute uveitis

Due to their unique characteristics, microemulsions (ME) represent one of the most promising delivery systems which can conquer poor ocular drug bioavailability providing long residence time. Development of a ME system, relying on the use of a safe and non-irritant surfactant combination derived from sustainable resources and which can consolidate the small ME droplets, is the goal of this work. Herein, we report the design and characterization of a novel biocompatible, eco-friendly ME system loaded with the hydrophilic dexamethasone sodium phosphate (DEXP) using a novel surfactant mixture composed of D-α-tocopherol polyethylene glycol succinate (TPGS) and Plantacare® (coco-Glycosides). Capryol™ PGMC and double-distilled water were used as the respective oil and aqueous phases and the MEs were prepared by the water titration method, suitable for scaling up. Optimization of ME formulae was conducted by varying Plantacare® grades, TPGS to Plantacare® mass ratios and drug loading. The formulae were characterized in terms of physical appearance, droplet size (PS), size distribution (PDI), zeta potential (ZP), and stability. The optimized DEXP-loaded ME formula attained acceptable PS, PDI, and ZP values of 43 ± 5 nm, 0.35 ± 0.07, -12 ± 4 mV, respectively. TEM images confirmed a small PS ≤ 100 nm. The in vivo safety of ME was proved by the Draize test. The ME formula prompted excellent mucoadhesion and transcorneal permeation. The confocal studies showed deep penetration into the rabbits' corneas. In vivo studies using endotoxin-induced uveitis showed high ocular efficacy and a significant reduction in inflammatory cells, including interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). The obtained results elect the novel engineered ME system as a promising tool for the ocular delivery of hydrophilic moieties in the management of various ophthalmic diseases.

Advances in Antiviral Delivery Systems and Chitosan-Based Polymeric and Nanoparticulate Antivirals and Antiviral Carriers

Current antiviral therapy research is focused on developing dosage forms that enable highly effective drug delivery, providing a selective effect in the organism, lower risk of adverse effects, a lower dose of active pharmaceutical ingredients, and minimal toxicity. In this article, antiviral drugs and the mechanisms of their action are summarized at the beginning as a prerequisite background to develop relevant drug delivery/carrier systems for them, classified and briefly discussed subsequently. Many of the recent studies aim at different types of synthetic, semisynthetic, and natural polymers serving as a favorable matrix for the antiviral drug carrier. Besides a wider view of different antiviral delivery systems, this review focuses on advances in antiviral drug delivery systems based on chitosan (CS) and derivatized CS carriers. CS and its derivatives are evaluated concerning methods of their preparation, their basic characteristics and properties, approaches to the incorporation of an antiviral drug in the CS polymer as well as CS nanoparticulate systems, and their recent biomedical applications in the context of actual antiviral therapy. The degree of development (i.e., research study, in vitro/ex vivo/in vivo preclinical testing), as well as benefits and limitations of CS polymer and CS nanoparticulate drug delivery systems, are reported for particular viral diseases and corresponding antivirotics.