Tewameter® TM 300
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What does it measure? The Tewameter® TM 300 is the worldwide most accepted measuring device for the assessment of the TransEpidermal WaterLoss (TEWL). This is the most important parameter for the evaluation of the water barrier function of the skin. The Measuring Principle The Tewameter® probe measures the density gradient of the water evaporation from the skin indirectly by the two pairs of sensors (temperature and relative humidity) inside the hollow cylinder. This is an open chamber measurement. A microprocessor analyses the values. A = surface [m2] dm =-D•A m = water transported [g] dt t = time [h] D = diffusion constant [= 0.0877 g/m(h(mmHg))] p = vapour pressure of the atmosphere [mm Hg] x = distance from skin surface to point of measurement [m] Fields of Application There is a wide field of applications for detecting even slight deficiencies in the barrier of the skin. • Indispensable in efficacy testing and claim support for cosmetics and pharmaceuticals. • Dermatological basic research. • Objective clinical trials of barrier improvement and mechanisms of product behaviour. • Sweat studies (anti-perspirant efficacy testing). • Demonstrative to alert people to specific occupational skin hazards. • Interesting applications in veterinary dermatology and zoology. • Also for the textile, food or paper/tissue industry the measurement is of interest. Technical Data Dim.: Hollow cylinder: 2 cm, ∅ 1 cm, Probe: 15.3 cm, Weight: 90 g, Resolution: Humidity: ± 0.01 % RH, Temp.: ± 0.01 °C, Accuracy within 10° C to 40° C and for TEWL-values lower than 70 g/hm²: rel. humidity (RH): ± 1.5 % RH in the range of 30 % RH to 90 % RH; ± 2.5 % RH in the range of 90 % RH to 100 % RH; ± 2.5 % RH in the range of 0 % RH to 30 % RH Waterloss: ± 0.5 g/hm² for RH ≥ 30 %; ± 1.0 g/hm² for RH ≤ 30 % , Temperature: ± 0.5 °C Technical changes may be made without prior notice. Advantages • The open chamber measurement is the only method to assess the TEWL continuously, which is necessary for most applications without influencing the skin surface. • Numerous studies available. • A stable measurement is achieved quickly, the next measurement can be done without waiting time. • The small size of the probe head minimizes the influence of air turbulence inside the probe. • Its low weight has no influence on the skin structure and ensures easy handling. • Check calibration can easily be done by a small chamber at any time. • Available for C+K MPA-System, as stand-alone device and wireless probe.

Special Features • Offset of probe by the user possible for compensation of “aging effects11 of the sensor. • Measurement with several probes at the same time possible (e.g. for the measurement of large areas or sweat studies). • Recording of the ambient conditions with the Ambient Condition Sensor RHT 100 to help to compare measurements taken at different times. • Special calculations i.e. SSWL (Skin Surface Water Loss - assessment of skin‘s water holding capacity after occlusion) are possible. • Even used for the SKIN-B project on the ISS in space (Study by DermaTronnier,...