346 JOURNAL OF COSMETIC SCIENCE Table I TEWL Values (SD) in g/m 2 x h [averages, standard deviations, median values, and boxes (25% and 75 % percentile)] 15 min M SD Median Box Spreading bath -0.92 1.01 -0.5 - 1.7/0.2 Tween 20: 18% -0.44 1.07 -0.5 -0.8/0.0 Tween 20: 47% 0.29 0.93 0.2 -0.6/1.0 Water 0.34 1.80 0.6 0.0/1.2 30 min M SD Median Box Spreading bath -0.63 1.19 -0.6 - 1.3/0.0 Tween 20: 18% -0.55 1.04 -0.6 -1.0/0.2 Tween 20: 47% 0.11 1.14 0.0 -0.4/0.5 Water 0.53 1.37 0.5 0.1/1.5 60 min M SD Median Box Spreading bath -0.91 1.17 -0.7 - 1.7/-0.2 Tween 20: 18% -0.07 1.33 -0.6 - 1.4/0.0 Tween 20: 47% 0.12 0.86 0.0 -0.7/0.7 Water 0.61 1.64 0.5 0.1/1.5 90 min M SD Median Box Spreading bath - 1.15 0.93 - 1.0 - 2.0/- 0.2 Tween 20: 18% -0.79 0.79 -0.6 -1.1/-0.5 Tween 20: 47% -0.15 1.21 0.0 -0.4/0.8 Water 0.31 1.19 0.5 0.1/1.2 120 min M SD Median Box Spreading bath - 1.28 1.16 - 1.1 - 1.7/-0.5 Tween 20: 18% -0.80 1.20 -0.6 -1.3/0.0 Tween 20: 47% -0.30 1.60 0.0 -1.0/0.6 Water 0.09 1.29 0.3 - 1.0/1.1 end of measurement period at a weakly significant level, so that no definite difference between these groups can be assumed. DISCUSSION The present study was performed with the aim of elucidating the influence of different bath oils with two distinct dissolution characteristics (spreading and dispersion bath oil) and different amounts of a non-ionic tenside on the state of hydration of the stratum corneum and transepidermal water loss, and therefore on barrier function and occlusiv- ity. Two questions were in focus: First, the question of the possible dehydrating and barrier-damaging effect of the non-ionic tenside. Second, the influence of the character of the bath oil (spreading vs dispersion oil bath) on these parameters. The dessicating effect of tensides is established, since the basic work of Blank and Shappirio (12). Gabard eta/. (2) as well as M/filler eta/. (3) could demonstrate a decrease

NON-IONIC TENSIDES 347 Table II Capacitance Values (corneometry) in Arbitrary Units [averages, standard deviations, median values, and boxes (25 % and 75 % percentile)] 15 rain M SD Median Box Spreading bath 1.99 9.96 1.5 - 6.4/10.9 Tween 20: 18% 2.10 4.89 1.1 - 1.5/5.9 Tween 20: 47% -3.20 4.51 -2.0 -5.9/0.0 Water -4.54 5.71 -5.7 -8.9/- 1.3 30 min M SD Median Box Spreading bath 12.74 3.88 12.9 10.0/15.4 Tween 20: 18% 0.41 5.08 1.8 -2.6/29.0 Tween 20: 47% -3.72 3.67 -3.5 -7.2/-1.3 Water -4.94 4.27 - 5.2 - 9.0/- 2.1 60 min M SD Median Box Spreading bath 10.47 4.81 10.0 6.7/13.7 Tween 20: 18% 0.90 5.47 1.4 -4.02/2.7 Tween 20: 47% -4.60 2.57 -3.8 -7.0/-2.4 Water -5.97 5.35 -4.5 - 10.4/- 1.2 90 min M SD Median Box Spreading bath 8.22 5.62 9.2 3.1/11.0 Tween 20: 18% 0.12 6.58 1.8 -3.0/5.1 Tween 20: 47% -4.13 3.31 -2.5 -6.5/-1.9 Water -4.65 4.47 -4.8 -7.4/- 1.9 120 min M SD Median Box Spreading bath 7.16 6.47 6.6 2.9/10.0 Tween 20: 18% 0.93 7.68 2.4 -2.0/6.3 Tween 20: 47% -1.65 4.48 -0.6 -9.1/1.8 Water -4.70 4.46 - 3.9 -9.4/0.0 in transepidermal water loss, and therefore in occlusivity, from a spreading oil bath. Gloor et al. could prove an interdependence between the stratum corneum lipids and tenside content and the amount of emollient in bath oils (4-6). Here, a lower tenside content leads to a higher lipid amount after application of a bath oil with emollients. Table III Differences Between TEWL Values 15 min 30 min 60 min 90 min 120 min Tween 20: 18% * * * * + * Tween 20: 47% ] Water Wilcoxon signed-rank test (, = p 0.01, + = p 0.05).