Conference Contribution Details
LI Ciortea, RE Imhof and P Xiao.
Poster, 1st Joint ISBS/ISDIS International Meeting, Seoul 2008.
The aim of this study was to assess the performance of a condenser-chamber TEWL instrument for barrier integrity testing. According to Netzlaff et al  open-chamber TEWL measurements appears to be of limited use for such tests, being able to detect only severe damage in the samples they examined. Problems identified included topically adhering water and the permeation of condensed water via capillary action through deliberately made pinholes in artificial membranes.
Topically adhering water is less of a problem with the condenser-chamber TEWL method, because the chamber microclimate provides consistent conditions for rapid evaporation, irrespective of ambient humidity. Topical water shows up as a transient peak in the recorded water vapour flux time-series curve, whereas the water diffusing through the membrane generally settles to a lower level. Such flux curves give detailed information about the properties of the membranes and the validity of the tests.
We report measurements using both artificial membranes (Sil-Tec and PTFE) and bio-membranes (excised human stratum corneum and epidermis) to illustrate the capabilities of this approach.
|||F Netzlaff, KH Kostka, CM Lehr and UF Schaefer. TEWL measurements as a routine method for evaluating the integrity of epidermis sheets in static Franz type diffusion cells in vitro. Limitations shown by transport data testing. European Journal of Pharmaceutics and Biopharmaceutics, 63, 44-50, 2006.|
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