In-vivo Transdermal Drug Diffusion Depth Profiling-A New Approach to Opto-Thermal Signal Analysis

Abstract

To measure the percutaneous penetration of the externally applied chemicals into human skin is very important for understanding how drugs can be delivered through the skin. Opto-thermal transient emission radiometry, or OTTER, is a new approach to such measurements which has been demonstrated to be suitable for measuring diffusion coefficients and partition constants in-vivo and in-vitro. We present a novel technique for analyzing opto-thermal signals to yield depth profiles of externally applied substances diffusing through skin. The mathematical background of the new technique, together with penetration depth profiles of different solvents into in-vivo human skin are presented.