Tabosa, M A M; Vitry, P; Zarmpi, P; Bunge, A L; Belsey, N A; Tsikritsis, D; Woodman, T J; White, K A J; Delgado-Charro, M B; Guy, R H (2023) Quantification of chemical uptake into the skin by vibrational spectroscopies and stratum corneum sampling. Molecular Pharmaceutics, 20 (5). pp. 2527-2535.

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Abstract

Evaluation of the bioavailability of drugs intended to act within the skin following application of complex topical products requires the application of multiple experimental tools, which must be quantitative, validated and, ideally and ultimately, sufficiently minimally invasive to permit use in vivo. The objective here is to show that both infrared (IR) and Raman spectroscopies can assess the uptake of a chemical into the stratum corneum (SC) that correlates directly with its absolute quantification by the adhesive tape-stripping method. Experiments were performed ex vivo using excised mammalian skin and measured chemical disposition in the SC as functions of application time and formulation composition. The quantity of chemical in the SC removed on each tape-strip was determined from the individually measured IR and Raman signal intensities of a specific molecular vibration at a frequency where the skin is spectroscopically silent and by a subsequent, conventional extraction and chromatographic analysis. Correlations between the spectroscopic results and the chemical quantification on the tape-strips were good and the effects of longer application times and the use of different vehicles were clearly delineated by the different measurement techniques. With this initial validation, it is now possible to explore the extent to which the spectroscopic approach (and Raman in particular) may be used to interrogate chemical disposition deeper in the skin and beyond the SC.

Item Type:	Article
Keywords:	skin penetration, infrared spectroscopy, Raman spectroscopy, stratum corneum sampling, drug uptake into skin
Subjects:	Analytical Science > Trace Analysis and Electrochemistry
Divisions:	Chemical & Biological Sciences
Identification number/DOI:	10.1021/acs.molpharmaceut.2c01109
Last Modified:	30 Jun 2023 13:34
URI:	https://eprintspublications.npl.co.uk/id/eprint/9768