Analysing the skin barrier from down under.

Over the past 40 years the Australian contribution to the field of skin science has been led by Michael Roberts. One of his earliest papers on membrane permeation was published in Nature, setting the scene for his huge contribution to both the fundamental understanding of skin permeability and the application of that knowledge to improved clinical outcomes, new delivery technologies and minimizing toxicological risk. His work has been characterized by a mechanistic, mathematical approach to defining skin permeation. He defined the parameters important to skin permeation, established structure-penetration relationships and demonstrated the importance of maximum flux from a clinical and toxicological viewpoint. Through his systematic approach, Mike showed a parabolic relationship between maximum flux and lipophilicity, and established that this is driven mainly by variations in solubility of the solute in the stratum corneum. One of the significant strengths of Mike's work is the ability to express biological concepts in mathematical terms. He has developed mathematical models that enhance our understanding of epidermal, dermal, deep tissue permeation and follicular transport. Throughout his career Mike has been involved in pioneering new technologies both for analysing the skin barrier and influencing permeation across it. His fundamental work in the area of iontophoresis provided models that defined the parameters influencing its permeation enhancement. Mike's research has been translated into improved clinical outcomes, reduced toxicological risk and changes to the regulation of skin products. This article provides an insight into Mike Roberts and the Australian contribution to skin science.