Shiseido has developed a method to assess the skin permeation of cosmetic ingredients using a novel spectrometry technology. The method involves tape stripping, acquiring two-dimensional data on the sampled area using spectrometry technology and converting that data to a clear image that shows permeation.
This achievement improves simple, quantitative and clear visualization of the state of permeation of active ingredients into the stratum corneum (SC) across cross-sectional surfaces compared with existing methods. Up until now, the most common method of visualizing the permeation state has been to permeate active ingredients on a part of the skin which can be surgically removed and observe cross sections using a fluorescence microscope. In recent years, methods such as using a confocal laser microscope to measure active ingredients on living subjects have been developed. However, all of those devices are cumbersome and time-consuming to operate and are only able to obtain unclear visual images. Furthermore,these devices are able to target only ingredients that emit fluorescence has posed a problem.
Therefore, Shiseido started developing an analysis method for consumers to visually understand the permeation state of active ingredients and as a means for Shiseido to advance research related to the permeation of active ingredients by enabling simple, quantitative and clear visual display including the depth direction of the state of permeation regarding cosmetic ingredients or skin constituents.
The first step in the process is to take multiple 2 cm2 samples of the stratum corneum (SC) where the ingredient has been applied using special adhesive tape, which is well-known as "tape-stripping." Then two-dimensional distribution data of target ingredients of each sampled SC is acquired utilizing the newly developed Desorption Electrospray Ionization-Mass Spectrometry Imaging (DESI-MSI) method, which detects target ingredients according to their molecular weights. DESI-MSI is conducted by spraying positive or negative electrically charged liquid droplets in a fine mist on the surface of the sample under atmospheric pressure, simultaneously extracting and ionizing substances from near the surface of the sample and detecting target molecules after inserting into a high-vacuum mass spectrometer. Two-dimensional quantitative distribution (flat surface) data is obtained by moving the spray position at a constant speed on the flat surface, whereby the data can be visualized and displayed as an image. A quantitative and clear visual display in terms of depth direction is obtained using multiple two-dimensional distribution data collected via DESI-MSI using a patent-pending data processing method. However, this cross-sectional visual display developed at this time provides approximated images via data processing that combines planar images.
A significant feature of the newly developed measuring method (DESI-MSI) is that it can analyze multiple ingredients at the same time in a single measurement process. Therefore, for research on the permeation state of cosmetics ingredients in the skin, this makes it possible to simultaneously analyze aspects that include other formulated ingredients and the relationship with constituents in the skin. By utilizing this feature, there is the potential of broader applications, including new cosmetics development with even stronger permeation strength and in-depth research on the elucidation of the state of permeation into the skin.
Going forward, Shiseido aims to apply this technology in cosmetics development, including developing cosmetic products with even stronger permeation strength, as well as research on the route and amount of active ingredients permeating into the skin. This technology has been applied as a method to evaluate the permeation strength of 4MSK, the company's whitening ingredient in its White Lucent Power Brightening Mask, which will be launched Feb. 1, 2013.