title: Advanced chemical imaging and comparison of human and porcine hair follicles for drug delivery by confocal Raman microscopy.
abstract: Hair follicles have recently gained a lot of interest for dermal drug delivery. They provide facilitated penetration into the skin and a high potential to serve as a drug depot. In this area of research, excised pig ear is a widely accepted in vitro model to evaluate penetration of drug delivery into hair follicles. However, a comparison of human and porcine follicles in terms of chemical composition has not been performed so far. In this study, we applied confocal Raman microscopy as a chemically selective imaging technique to compare human and porcine follicle composition and to visualize component distribution within follicle cross-sections. Based on the evaluation of human and porcine Raman spectra optical similarity for both species was successfully confirmed. Furthermore, cyanoacrylate skin surface biopsies, which are generally used to determine the extent of follicular penetration, were imaged by a novel complementary analytical approach combining confocal Raman microscopy and optical profilometry. This all-encompassing analysis allows investigation of intactness and component distribution of the excised hair bulb in three dimensions. Confocal Raman microscopy shows a high potential as a noninvasive and chemically selective technique for the analysis of trans-follicular drug delivery.
authors.affiliation: Saarland University, Department of Biopharmaceutics and Pharmaceutical Technology, Saarbruecken, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Franzen
authors.forename: Christiane
authors.initials: C
authors.lastname: Mathes
authors.forename: Steffi
authors.initials: S
authors.lastname: Hansen
authors.forename: Maike
authors.initials: M
authors.lastname: Windbergs
mesh_terms: D000818:Animals; D001706:Biopsy; D003487:Cyanoacrylates / Q000737:chemistry; D016503:Drug Delivery Systems; D005260:Female; D018859:Hair Follicle / Q000033:anatomy & histology* / Q000737:chemistry*; D006801:Humans; D018613:Microscopy, Confocal / Q000379:methods*; D008875:Middle Aged; D023421:Models, Animal; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013552:Swine
chemical_list: D003487:Cyanoacrylates