Mini Review: Mass Spectrometry Technology for Molecule Distribution inside Skin

Abstract

The functional ingredients for skin-related products have been highly recognized accompanied by the consumers’ curiosity and instrumental improvement. The targeted location of a functional active ingredient in the skin organelle could be very critical information for its product development, safety evaluation, and benefit claims. Due to those factors, mass spectrometry technology exhibited rapid growth in those research areas because it can accurately and sensitively determine the ingredient molecular weights and locations. In this min review, a summarized figure was created for mass spectrometry technology applications in skin research in the last two decades or so. Compared to other related technologies, the uniqueness and advantage of chromatographic-mass spectrometry and mass spectrometry imaging were also emphasized. Several typical examples from separation, isotopic labeling, and combination with Franz cell were discussed.

Optical Methods for Non-Invasive Determination of Skin Penetration: Current Trends, Advances, Possibilities, Prospects, and Translation into In Vivo Human Studies

“…Tape-stripping-based lowinvasive ATR-FTIR and EPR spectroscopy methods are commonly used in in vivo skin penetration studies, but require special permission and are severely limited in patients. Low-invasive methods can be applied both in vivo and ex vivo and include tape stripping, primarily applied at the SC [16][17][18]; cyanoacrylate stripping applicable to the SC and viable epidermis [18,19]; suction blister after the application of partial negative pressure on the skin with further analysis of the accumulated interstitial and serum fluids [20]; sampling of the interstitial fluid from the viable epidermis and/or dermis with microneedles [21][22][23] or by microdialysis [24,25], followed by an analysis with validated methods (or their combinations) such as autoradiography for the detection of the radioisotopelabelled penetrants [26], high-performance liquid chromatography, mass spectrometry of various modifications, or UV/VIS spectroscopy (absorption or (epi)fluorescence in a specific spectral range) [26][27][28][29][30]. The skin penetration profile can be determined using low-invasive attenuated total reflectance Fourier-transform infrared (ATR-FTIR) [31][32][33], Fourier-transform infrared photoacoustic spectroscopy (FTIR-PAS) [31], thermal emission decay-Fourier-transform infrared (TED-FTIR) spectroscopy [34], and electron paramagnetic resonance (EPR) spectroscopy [35] for the analysis of the SC removed from skin with tape or cyanoacrylate stripping.…”