A Critical Comparison of Methods to Quantify Stratum corneum Removed by Tape Stripping

Abstract

Skin surface stripping with adhesive tape has been used to study the barrier function of the stratum corneum. Usually, the amount of stratum corneum removed by stripping is not linearly proportional to the number of strips removed. The generally accepted quantitative method to determine the amount of stratum corneum material on a tape strip is weighing. This method however has certain drawbacks, it is time consuming and laborious because tape strips have to be weighed twice and sometimes it cannot be used to determine concentration profiles in the skin of active substances in topically applied vehicles. In this paper, the accuracy and reliability of an alternative method to determine the amount of stratum corneum removed by tape stripping of the skin was investigated and compared to weighing. It is based on the spectrophotometric examination of the tape. The light absorption by the proteins on the tape is correlated to the weight of the stratum corneum material. This method was found to be easier and faster than weighing, but it was less reliable because the light scattering of the stratum corneum on the tape largely overshadowed the absorption of the proteins. The light scattering showed a linear increase with an increasing amount of material on the tape, but with a large variability, resulting in calibration curves with correlations of 0.8400. However, direct spectroscopic analysis of stratum corneum tape strips has some distinct advantages even if it cannot be used for the exact quantification of stratum corneum proteins. With direct spectroscopic measurements, a tape strip can be laterally examined to inspect its homogeneity. Direct spectroscopic measurements on tape strips might also be employed to investigate the lateral and in-depth distribution of strongly light-absorbing substances in the stratum corneum.

The Tape-Stripping Technique as a Method for Drug Quantification in Skin

“…TS appears to be simple and easy to perform [39][40], however there are different parameters that can influence the quantity of SC removed by a piece of tape, and these include TS mode [38,41], skin hydration, cohesion between cells (which increases with SC's depth), the body site and inter-individual differences [9,42]. The impact of these factors has been frequently investigated [8,[38][39][40][41][42][43][44].…”

“…Moreover, in vitro methods are encouraged by regulatory agencies regarding the provision of percutaneous absorption data for drugs, pesticides and cosmetics [62]. All these points are emphasized in Table 1, which summarizes the research with the TS technique to determine the kinetics and penetration depth of permeants (drugs and toxic chemicals) [7,26,35,37,44,, in order to evaluate the factors that influence the physiology of the SC [42,44,105,106], to determine the composition of the SC [108], superficial infections in the skin [110,111], and evaluate skin regeneration [112,113], etc.…”

“…The anatomical region also influences lipid distribution [101,102], microflora [103] and physical parameters such as TEWL [104]. However, there are already a few studies reporting conflicting results for the effect of gender [105] on skin physiology, as well as for the effect of anatomical site, pressure, pressure duration and tape removal rate in skin physiology [42], or the effect of skin transport technology, as iontophoresis, on human skin [106].…”

Mass Spectrometry in Cosmetic Science: Advanced Ionization Techniques for Detecting Trace Molecules in or on Human Skin

“…e tape-stripping technique 16,17) is also used in cosmetic science as a convenient method to rapidly and noninvasively collect stratum-corneum samples.…”

“…In addition to conventional analytical methods, such as LC-MS, LC-MS/MS, GC-MS, GC-MS/MS, for bulk-sample analysis, two-dimensional (2D) desorption electrospray ionization 12,13) MS imaging (DESI MSI) and zero-volt paperspray ionization MS (zvPSI-MS) 14,15) have been introduced to obtain highspatial-resolution molecular distributions and rapid pro le information, respectively, with minimal sample pretreatment. As described in more detail in the following sections, 2D-DESI MSI, in conjunction with the tape-stripping stratum-corneum sampling technique, 16,17) and zvPSI-MS are tools that promise to accelerate progress in the eld of cosmetic science.…”