Selective probing of the penetration of dexamethasone into human skin by soft x-ray spectromicroscopy

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Item Type:	Article
Title:	Selective probing of the penetration of dexamethasone into human skin by soft x-ray spectromicroscopy
Creators Name:	Yamamoto, K., Flesch, R., Ohigashi, T., Hedtrich, S., Klossek, A., Patoka, P., Ulrich, G., Ahlberg, S., Rancan, F., Vogt, A., Blume-Peytavi, U., Schrade, P., Bachmann, S., Schäfer-Korting, M., Kosugi, N. and Rühl, E.
Abstract:	Selective probing of dexamethasone in excised human skin using soft X-ray spectromicroscopy provides quantitative concentration profiles as well as two-dimensional drug distribution maps. Element- and site-selective excitation of dexamethasone at the oxygen K-edge with the lateral step width adjusted to 1 μm provides detailed information on the location of the drug in the different skin layers. The key of this work is to probe dexamethasone selectively at the carbonyl site (C3) by the O 1s → π* transition, providing also a most efficient way to quantify the drug concentration as a function of penetration depth in correlation with structural properties of the skin containing carboxyl and amide oxygen sites occurring at higher transition energy than dexamethasone. Following drug exposure for 4 h, the glucocorticoide is located in about equal amounts in the stratum corneum, the outermost horny layer of skin, and in the viable epidermis, whereas in the dermis no dexamethasone is detected. In the stratum corneum, most of the lipophilic drug is found in regions between corneocytes, where epidermal lipids are dominating.
Keywords:	Dexamethasone, Healthy Volunteers, Molecular Conformation, Skin, Spectrum Analysis, X-Rays
Source:	Analytical Chemistry
ISSN:	0003-2700
Publisher:	American Chemical Society
Volume:	87
Number:	12
Page Range:	6173–6179
Date:	16 June 2015
Official Publication:	https://doi.org/10.1021/acs.analchem.5b00800
PubMed:	View item in PubMed

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