HUMAN SKIN GRAFTED NUDE MOUSE 261 Figure 5. Stratum corneum of the human skin transplant. 5C. After 20 strippings. moters for many other substances (21). In fact, those additives themselves had high affinities for the stratum corneum when they were applied as single substances as is shown in Table II. All the cosmetic bases employed for the present investigation seem to have reduced the amount of Aqualizer retained by the stratum corneum (Table III). However, the lotion-

262 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Table I Recovery of •4C-Labeled 0.14% w/v Lactic Acid at pH 7 With a Specific Activity of 12 •Ci/ml From Four Experimental Sites of a Nude Mouse at Zero Time % of Applied Radioactivity Recovered in 20 Strips Left Right Left Right Front Front Back Back Swabs 99.28 98.71 98.65 98.92 Tape Strippings 0.56 0.53 0.74 0.69 Total Recovery 99.84 99.24 99.39 99.61 Each result is the mean of the readings obtained using two mice. Applied amount is 5 microliters. Table II Stratum Corneum Uptake of Some of the Main Ingredients of NMF % of Applied Radioactivity Recovered in 20 Strips Specific Concentration Human Mouse Skin Mouse Skin Mouse Skin Ingredient Activity % w/v pH Transplant Right Front Left Back Right Back Lactic Acid 12 •Ci/ml 0.14 7.0 6.78 4.23 5.43 7.00 Alanine 7 •Ci/ml 0.07 6.0 5.93 4.05 4.53 4.25 Urea 7 •Ci/ml 0.1 7.2 17.13 14.76 16.54 15.41 Recovery time is four hours. Each result is the mean of the data obtained using two mice. 5 microliters of test material was applied to 1 cm 2 test area. Table III Stratum Corneum Uptake of 10% w/w Radiolabeled NMF Condensate and Aqualizer From Different Cosmetic Bases % of Applied Radioactivity Recovered in 20 Strips Type Human Skin Mouse Skin Mouse Skin Mouse Skin Applied Substance of Base pH Transplant Right Front Left Back Right Back NMF Condensate Aqueous 5.42 1.36 1.29 2.11 1.45 in Water Solution Aqualizer in water Aqueous 6.28 3.45 3.51 2.48 Solution Aqualizer in A Enriched 5.88 1.11 0.69 1.52 0.68 Cream, w/o Aqualizer in B Moisture 5.87 1.14 1.05 1.28 0.28 Cream, w/o Aqualizer in C Moisture 4.28 2.03 1.19 2.11 1.48 Lotion, o/w Aqualizer in D Moisture 5.86 1.45 2.26 2.07 2.14 Lotion for Oily Skin o/w Recovery time = 4 hrs. Each value is the mean of three replicates.