Tape stripping technique

The pH of intact skin ranges from about 4.8 to 6.0, while interstitial fluid exhibits a pH that is near neutral. The low pH on skin is attributed mainly to the presence of the so-called acid mantle , a natural skin barrier to the external environment [172], Wagner et al. [173] measured both in-vivo and in-vitro pH profiles across human stratum comeum (SC) using the tape stripping technique and a flat surface pH electrode (InLab 426 from Mettler Toledo). They found a steep pH increase from pH 6 to 8 in the first 100 pm after the removal of the SC. 

The tape-stripping technique has been applied in vivo, as well as in vitro. The used in vitro incubation devices are the same as described for skin permeation studies. A specialized incubation device developed by Loth and coworkers, the Saarbriicken penetration model, allows investigation of skin penetration bypassing the normally occurring nonphysiological hydration of the dermis [64],... 

Lanolin appears to penetrate into the stratum corneum, but remains in the more superficial layers.38 39 Using the tape stripping technique, Clark demonstrated the penetration of anhydrous lanolin (2 mg/cm2) applied to the flexor aspect of the inner forearm.40 Almost all of the applied lanolin was recovered and most was removed in the first 15 strippings. Although the bulk of lanolin may remain in the superficial layers, electron-dense lead linoleate and lead oleate topically applied in lanolin were observed by transmission electron microscopy to be localized in intracellular spaces as far down as the stratum granulosum 40... 

Surber, C., Schwarb, F.P., and Smith, E.W., Tape-stripping technique, in Percutaneous Absorption Drugs — Cosmetics—Mechanisms—Methodology. Bronaugh, R.L. and Maibach, H.I. (Eds.), 3rd edn. Drugs Pharm. Sci. 97, 1999, 395M09. 

Pellet MA, Roberts MS, and Hadgraft J. Supersaturated Solutions Evaluated with an In Vitro Stramm Corneum Tape Stripping Technique. 1997 151 91-98. 

Pellett, M. A., M. S. Roberts, and J. Hadgraft. 1997. Supersaturated solutions evaluated with an in vitro stratum corneum tape stripping technique. Int.. Pharm. 151 91-98. 

A simple, quahtative method is the skin stripping technique (322) which strips off a sampling from the skin with ceUophane tape. Methods have been developed (330,331) in which organisms on the hands ate transferred to gloves and sampled. These methods assess both immediate and persistent effects of antiseptics. In aH tests with antiseptics, suitable neutralizing chemicals for the antiseptics employed are necessary so that surviving bacteria may be recovered and counted. Some of these are lecithin, Lubrol W, Polysorbate, and sodium thiosulfate (322). 

The outermost skin layer, the stratum corneum (SC), consists of corneocytes embedded in lipid layers and represents the main barrier for skin penetration of xenobiotics. Its thickness in healthy adults may vary from 5 to 20 /um, except in the palm and sole where it is much thicker. SC can be removed sequentially by repeated application of appropriate adhesive tapes.1 This technique, commonly known as SC tape stripping, is a relatively noninvasive method to investigate the structure, properties, and functions of SC in vivo2 and is the most frequently used for such purposes. Other techniques to remove SC are skin surface biopsy using cyanoacrylate strips and skin scraping. 

Whole-animal studies assess the percent of the applied dose absorbed into the body using classic techniques of bioavailability, where absorbed chemical is measured in the blood, urine, feces, and tissues with mass balance techniques. Recently, methods have been developed to assess absorption by measuring the amount of chemical in the stratum comeum because it is the driving force for diffusion. Cellophane tape strips are collected 30 minutes after chemical exposure and the amount of drug assayed in these tape strips correlates to the amount systemically absorbed. If the focus of the research is to determine the amount of chemical that has penetrated into skin, core biopsies may be collected and serially sectioned, and a profile of the chemical as a function of skin depth may be obtained. 

There are few published data on the percutaneous absorption of sunscreens through human skin (239,242-248). Most of the information came from in vitro penetration studies or by estimation from the amount recovered in the stratum corneum after tape stripping. The rationale for using the latter method (often referred to as the "reservoir technique") is based on the finding by Treffel and Gabard (248)that a linear relationship exists between the drug concentration in the stratum corneum and its in vivo percutaneous absorption. 

The tape-stripping method initially described by Rockl et al. [19,20] appears to be a valuable and versatile tool for providing information on the distribution of bacteria in and on the skin [19-21], The tape method has been used as a reliable inexpensive diagnostic tool for quantitative determination of, for example, Pityro-sporum yeast [22], Candida spp. [23], Enterobius spp. [24], and Trichophyton spp. [25], The tape method was found to be more sensitive than swab testing, skin scraping, and direct impression techniques for the determination of quantitative and distribution data of Malassezia spp. on canine skin [26],... 

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