Study of the diffusion of an emulsion in the human skin by pulsed photoacoustic spectroscopy: experiment and numerical simulation

¹ Département de Physique, Faculté des Sciences de Meknès, Université Moulay Ismaïl, BP 4010, Beni M'hamed, Meknès, Morocco
² École Nationale des Sciences Appliquées de Tanger, Université Abdelmalek Essaâdi, Route Ziaten, km 10, BP 416, Tanger, Morocco
³ Department of Chemistry, University of Miami, Cox Science Building, 1301 Memorial Drive, PO Box 249118, Miami, FL 33124-0431, USA

Corresponding author: nabil_benamar@yahoo.fr

Received: 14 July 2003
Revised: 29 April 2004
Accepted: 7 May 2004
Published online: 6 July 2004

Abstract

We previously used the Pulsed Photoacoustic Spectroscopy to quantify sunscreen chromophore diffusion into human skin, and suggested a methodology to evaluate the time and the depth diffusion profile into human skin. In the present study we present the results obtained for the diffusion of an emulsion in human skin, which is used in the sunscreen compositions. This study shows, for the first time, a particular behaviour due to a chemical reaction inside the skin during the diffusion process. This result brings a particularly interesting technique through the PPAS spectroscopy, to evaluate in situ, the eventual chemical reactions that can occur during drug diffusion into human skin. Numerical simulation allows us to understand the impact of thermal, optical and geometrical parameters on the photoacoustic signal and thus the physics of the diffusion phenomenon. The present simulation shows clearly that the values corresponding to the maximum of the photoacoustic signal magnitude, , decrease when the thickness, , of the sample decrease. Conclusions about possibilities and limitations of the considered model are discussed.