Conference Contribution Details


George Kramer, Perry Xiao, Jonathan Crowther & Bob Imhof
Poster Presentation, SCC Annual Scientific Meeting & Technology Showcase, New York 2015.



With increasing globalisation, multi-location clinical trials of topical products are becoming more commonplace. In such trials, it is important to use instruments that are accurately calibrated, to ensure comparability at different locations. But even accurately calibrated instruments may perform differently at different locations, if their readings are affected by atmospheric pressure, as may be the case with TEWL instruments. The effect of atmospheric pressure and temperature on open-chamber TEWL measurements was first investigated by Nilsson [1]. He concluded that readings could change by as much as ±6% depending on weather conditions. Altitude-related changes were not considered, but they can be significantly bigger. For example, open-chamber TEWL readings in New York (~sea level) and Denver (~1600m altitude) would differ, according to Equation (2) of [1], by ~20%. It is not clear whether closed-chamber instruments are affected by atmospheric pressure in the same way as open-chamber instruments. To find out, we performed measurements using condenser-chamber AquaFlux™ (Biox Systems Ltd, England) and unventilated-chamber VapoMeter (Delfin Technologies Ltd, Finland) instruments, at locations spanning an altitude range 80-1700m. The findings will be reported in the poster.


1. Nilsson GE. Measurement of water exchange through skin. Med Biol Comput. 1977;15:209-18.


Click here to download the poster handout (pdf format, 0.6MByte).