Transdermal drug delivery systems for fighting common viral infectious diseases

Abstract

Transdermal drug delivery systems (TDDS) have many advantages and represent an excellent alternative to oral delivery and hypodermic injections. TDDS are more convenient and less invasive tools for disease and viral infection treatment, prevention, detection, and surveillance. The emerging development of microneedles for TDDS has facilitated improved skin barrier penetration for the delivery of macromolecules or hydrophilic drugs. Microneedle TDDS patches can be fabricated to deliver virus vaccines and potentially provide a viable alternative vaccine modality that offers improved immunogenicity, thermostability, simplicity, safety, and compliance as well as sharp-waste reduction, increased cost-effectiveness, and the capacity for self-administration, which could improve vaccine distribution. These advantages make TDDS-based vaccine delivery an especially well-suited option for treatment of widespread viral infectious diseases including pandemics. Because microneedle-based bioassays employ transdermal extraction of interstitial fluid or blood, they can be used as a minimally invasive approach for surveying disease markers and providing point-of-care (POC) diagnostics. For cutaneous viral infections, TDDS can provide localized treatment with high specificity and less systemic toxicity. In summary, TDDS, especially those that employ microneedles, possess special attributes that can be leveraged to reduce morbidity and mortality from viral infectious diseases. In this regard, they may have considerable positive impact as a modality for improving global health. In this article, we introduce the possible role and summarize the current literature regarding TDDS applications for fighting common cutaneous or systemic viral infectious diseases, including herpes simplex, varicella or herpes zoster, warts, influenza, measles, and COVID-19.

Keywords: Microneedle vaccine; Microneedles; Transdermal drug delivery; Transdermal patches; Transdermal sampling; Viral infection.

Fig. 1

Different types of microneedles and their characteristics. (A) The structures of solid, hollow, coated, polymer, and hydrogel microneedles. (B) Each of these microneedles has different drug delivery properties. Solid microneedles are well suited for penetration and increasing drug permeability. Hollow microneedles create pathways for drug infusion. Coated microneedles contain drugs on their surface that dissolve after insertion into the skin. Microneedles made with biocompatible and biodegradable polymers contain drugs that fully dissolve in the skin to release their encapsulated reagents. Hydrogel microneedles made with non-dissolving, liquid-absorbing materials can be used for fluid and materials diffusion