ASSESSING SKIN BARRIER INTEGRITY 179 • 5 • 4 I I I I I 0 1 2 3 4 5 Time (Weeks) Figure 2. Effect of storage temperature on the permeation of water through micro-Yucatan pig skin (skin stored before dermatoming). ß 4øC, ¸ -15øC. * Statistically significant value from the initial result. Each error bar represents the standard error of the mean. EFFECT OF STORAGE TEMPERATURE ON THE PERMEATION OF WATER AND SALICYLIC ACID THROUGH MICRO-YUCATAN PIG SKIN WHEN THE SKIN WAS DERMATOMED AND DRIED BEFORE STORING Plots of the cumulative amounts of water and SA permeating through micro-Yucatan pig skin over time were linear during the four-week period of testing (r 0.987 in all cases). Water and SA fluxes were calculated and plotted as a function of time in Figures 6 and 7, respectively. It was clear that storing skin for a period of four weeks at 4øC after drying and dermatoming did not affect its permeability for either water or SA. When skin was stored at - 15 øC, its permeability to water was unchanged, but its permeability to SA was somewhat affected. The flux ratios did not change remarkably during the experiment. PERMEATION OF WATER AND SA THROUGH VENTRAL AND DORSAL YUCATAN PIG SKIN Cumulative amounts of water and SA permeating over time through ventral and dorsal pig skin were obtained. The values of water and SA fluxes were calculated and are

180 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 0.030 0.025 0.020 0.015 0.010 0.005 0.000 I I I I I 0 1 2 3 4 5 Time (Weeks) Figure 3. Effect of storage temperature on the permeation of salicylic acid through micro-Yucatan pig skin (skin stored before dermatoming). ß 4øC, ¸ -15 øC. * Statistically significant value from the initial result. Each error bar represents the standard error of the mean. Table I Water/SA Flux Ratios During the Four-Week Period of Study Storage condition Skin dermatomed Skin stored before Skin dermatomed and dried dermatoming before storage before storage Time (weeks) 4øC - 15 øC 4øC - 15 øC 4øC - 15 øC 0 292.3 292.3 281.2 281.2 281.2 281.2 1 322.0 329.2 212.4' 295.7 270.4 273.8 2 470.0* 397.6* 320.2 340.4* 280.0 281.0 3 329.0 251.4 330.2 332.3* 270.2 236.7 4 368.5* 251.6 313.3 294.4 293.2 296.1 * Statistically different from initial results.