COSMETIC FILMS ON THE SKIN Table I Moisture Uptake of Skin 157 Moisture Uptake in Material 48 Hours at 90% R.H. (%) Untreated skin Extracted skin reimpregnated with NMF extracted from human skin Extracted skin reimpregnated with synthetic NMF (Aqualizer E-J) 49.5 19._2 26.0 44.5 Table II Penetration of NMF into Stratum Corneum Layer of Stratum Corneum a Second Third Fourth Fifth Reaction N R N R N R N R Untreated skin 1.5 0.7 2.4 1.3 2.7 1.3 2.7 2.1 Extracted skin 0.1 0.8 0.3 0.6 0.2 0.7 0.3 0.7 Extracted skin reimpregnated with skin extract 1.0 1.3 1.0 1.0 1.5 0.5 1.8 0.8 Extracted skin reimpregnated with Aqualizer E-J 2.5 1.8 2.8 2.2 2.8 2.2 3.0 2.5 a The first or outermost layer was discarded to eliminate material clinging to the skin sur- lace. Table III Effect of Different Oils on Insensible Perspiration of the Living Human Skin Insensible Perspiration Materialsa (%) Uncovered skin Skin covered with human sebum Skin covered with petrolatum Skin covered with Eucerin b (an absorption base) Skin covered with 50% petrolatum and 50% lanolin Skin covered with preen gland oil of ducks c lOO 95 37 61 60 97 a Applied at the rate of 1 mg/cm 2. b Beiersdorf & Co., A.G., Hamburg, Germany. c Isolated from preen glands in the Biochemischen Institut, Universit/it Tfibingen, Ger- many.

158 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Table IV Effect of Branched-Chain Aliphatic Compounds on Insensible Perspiration Invisible Water Vapor Release Materials a ( %)b 10-Methyl stearic acid triglyceride 4-Methyl laurie acid triglyceride 2,7-Dimethyl-octadienol 2,7- Dimethyl-octanol 2,7-Dimethyl-octyl laurate 2,6-Dimethyl-octenyl laurate 98 99 100 100 99 98 Applied at rate of 1 mg/cm • of skin. Normal skin value is 100. Table V Effect of Mixtures of Branched and Straight-Chain Aliphatic Compounds on Insensible Perspiration Branched-chain Compound Materials a Added Insensible Water Corn- Vapor pound Released Added from the (%) Skin (%) None None 0 100 Petrolatum None 0 38 Petrolatum 3,5-dimethylmyristic acid 10 62 Petrolatum 2,6-dimethyl-octyl palmitate 10 71 50% petrolatum plus 50% lanolin None 0 62 50% petrolatum plus 50% lanolin 2,6-dimethyl-laurie acid 10 84 50% petrolatum plus 50% lanolin 2,6 dimethyl-octyl palmitate 10 82 50% petrolatum plus 50% lanolin 3,7-dimethyl-octyl-3,7-dimethyl ottoate 10 84 50% petrolatum plus 50% lanolin 4-methyl-laurie acid triglyceride 25 94 a Applied at level of 1 mg/cm • of skin. perspiration of the skin. If branched-chain compounds are added to cosmetic bases in amounts of 5-10%, the ocdusiveness of these bases can be overcome. Films of these bases form porous films on the skin surface as shown by the results in Table V.* Because the complete composition of the skin's NMF was unknown and because so-called moisturizers (humectants) were apparently not effective enough, it has been recom- mended by several researchers to use occlusive fat films on the skin surface to prevent drying out of the stratum corneum. In this way it was hoped to help control the moisture content of the skin. As shown * The use of branched-chain compounds in cosmetic preparations is covered by U. S. Patent 3,035,987.