Build a solid foundation in science, formulation and product development—find out more!
Most Popular in:
Tape Stripping Method in Humans: Comparison of Evaporimetric Methods
By: Hongbo Zhai, MD, and Howard I. Maibach, MD, University of California School of Medicine
Posted: January 30, 2009, from the February 2009 issue of Cosmetics & Toiletries.
page 2 of 5
Instruments: TEWL was assessed by an open chamber deviceb and a closed chamber devicec. The measuring principle and standard guidelines are published.10,11 The values of TEWL were expressed as g/m2 per hr.
Experimental design: This study was randomized; each test area was chosen in a random manner. Each volunteer served as his or her own control between the different test regions.
General procedure: In a random manner, the TEWL on one forearm of each subject was measured with the open chamber device and the TEWL on the opposite forearm was measured with the closed chamber device. After recording baseline measurements, 20 tape strippings were taken on each test site with the skin sampling discs. TEWL was re-measured following 10 and 20 tape strippings at each test site.
Tape stripping: The skin sampling disc was placed on the test sites with forceps, utilizing gloved hands. The disc was pressed onto the skin using a roller. The roller was then removed and the tape disc peeled from the skin with forceps in a unidirectional manner for all sites. Twenty tape strips were taken from each test site. Immediately after each tape stripping, individual tape was placed into a scintillation vial. These strips were analyzed to quantify the amount of removed SC with a modified protein assay.
Protein assay: SC aggregates in the strips were analyzed with a modification of Dreher’s method; details can be found elsewhere.6,12 TEWL measurements were conducted in a room with daily relative humidity (RH) of 43.3 ± 3.1% and temperature of 18.8 ± 1.3°C. These values (RH and °C) were recorded throughout the experimental period. Each subject rested for at least 30 min to acclimate before measurements.