Modeling drug transport within the viable skin - a review

ABSTRACT

Introduction

In the past, mathematical modeling of the transport of transdermal drugs has been primarily focused on the stratum corneum. However, the development of pharmaceutical technologies, such as chemical enhancers, iontophoresis, and microneedles, has led to two outcomes; an increase in permeability in the stratum corneum or the ability to negate the layer entirely. As a result, these outcomes have made the transport of a solute in the viable skin far more critical when studying transdermal drug delivery.

Areas covered

The review will explicitly show the various attempts to model drug transport within the viable skin. Furthermore, a brief review will be conducted on the different models that explain stratum corneum transport, microneedle dynamics and estimation of the diffusion coefficient.

Expert opinion

Future development of mathematical models requires the focus to be changed from traditional diffusion-based tissue models to more sophisticated three-dimensional models that incorporate the physiology of the skin.

KEYWORDS:

• Transport
• viable skin
• modeling
• toxicity
• diffusion
• microneedle
• capillary

Article highlights

• The review provides a brief overview of important models and reviews conducted in the stratum corneum.

• However, it focusses on the importance of modelling the viable skin and its relevant physiology.

• In particular, it discusses the effects of the vasculature system in the dermis.

• The different attempts to develop an effective diffusion coefficient in the viable skin have also been discussed.

• Previous modelling of microneedle application and its impact to drug transport has also been summarised.

• Finally, the review features an expert opinion on future developments in the field.

• This box summarizes key points contained in the article.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.