Tape stripping of human stratum corneum yields cell layers that originate from various depths because of furrows in the skin

Tape stripping of human stratum corneum is widely used as a method for studying the kinetics and penetration depth of drugs, Several factors can influence the quantity of stratum corneum that is removed by a piece of tape, such as the manner of tape stripping, the hydration of the skin, cohesion between cells, body site and interindividual differences, However, few data are available about the influence of furrows in the human epidermis on the tape-stripping technique, In this study, we investigated the efficacy of tape stripping in removing complete cell layers from the superficial part of the human stratum corneum, A histological section of skin that was tape-stripped 20 times clearly showed nonstripped skin in the furrows, indicating persistent incomplete tape stripping, Replicas of tape-stripped skin surface demonstrated that even after removing 40 tape strips the furrows were still present, We validated the tape-stripping method further with X-ray microanalysis in the mapping mode by scanning electron microscopy, using a TiO2-containing compound as a marker, TiO2 applied to the skin before the tape-stripping procedures was still present after the tenth tape strip, and was specifically located on the rims of the furrows, We emphasize that results from studies using the tape-stripping method have to be viewed from the perspective that cells on one tape strip of the stratum corneum may be derived from different layers, depending on the position of the tape strip in relation to the slope of the furrow, and such results should be interpreted with considerable caution.