The clinical efficacy of any cosmetic or medicinal skin active is determined not only by its intrinsic activity, but also by its delivery to the site of action. Pre-clinical skin delivery studies are, therefore, essential in ensuring that active delivery is maximized and that clinical tests are successful.
FTIR Spectroscopy and Raman Spectroscopy enables us to visualize and quantify the distribution of a particular molecule or ingredient on the skin surface or in a skin cross-section. The key advantage of FTIR and Raman imaging is that is often possible to image active delivery without needing to chemically modify, or ‘tag’, the active. Formulations can be applied as supplied.
FTIR imaging experiments involve imaging the distribution of actives on the skin surface, in skin tape strips or in skin cross-sections. Raman imaging experiments can be performed on intact skin or in skin cross-sections. Experts at TRI can advise you on the best experimental design for your products.
TRI also has a portable FTIR spectrometer with an optical probe (RemSpec). This instrument cannot do imaging experiments but can be used in a clinical setting (working in partnership with a clinical test house) to quantify active levels on the skin and on tape-stripped skin.
FTIR imaging on tape-stripped skin; Investigation of penetration of new active (P) versus glycerin. The new active can be seen to penetrate deeper into the stratum corneum.
Comparison of relative content of caffeine using confocal Raman imaging: between four different formulations at different time points (a); and measured by the peak area ratio between the caffeine band at 744 cm-1 and the phenylalanine band (b).