886 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS become immune to irritants. This suggested its possible use as an anti-irritant. However, it was shown above that addition of 1% glycogen to a cream containing proteolytic enzymes increased primary irritation in one very small scale test. Lanolin Masters (27) quotes a 1935 paper that addition of lanolin to diph- theria antitoxin helped guinea pigs survive 40X normally lethal doses. Hatschek and Rogicky (28) reported that benzpyrene-induced cancer growth is retarded by subsequent application of lanolin. Russell and Hoch (29) published detailed documentation of eye irritation tests on a shampoo containing 3% ethoxylated lanolin alco- hols plus 1% liquid lanolin ("Nimcolan S" and "Lantrol" of the Maim- strom Chemical Co.). Significant reduction in Draize test scores were reported by three out of five testing laboratories. Similarly, the addi- tion of 2% acetylated ethoxylated lanolin alcohols and esters (Solulan 98 of American Cholesterol Products, Inc.) to a commercial shampoo reduced total eye irritation to about one-third in one test (30). N(2-Itydroxyethyl) Palmitamide This substance was found to be the active factor common to egg yolk, peanut oil and soybean lecithin which provides anti-inflammatory activity vs. cultures of micrococcus pyogenes var. aureus (26). N-Lauroyl Sarcosinates A well-documented patent by Dvorkovitz (23) shows the benefit of adding "Sarkosyl NL-100" (sodium N-lauroyl sarcosinate, Geigy Chemical Co.) to various dishwashing detergent formulations. Skin irritations (after intradermal injection of rabbits) were reduced to as low as one-eighth "normal" by addition of up to 9% of this substance. Maypon •C Nassau (31) claimed that a mixture of 25% of this protein-coconut fatty acid condensate (available from Stepan Chemical Co.) with 75% sodium lauryl sulfate gives much less eye irritation than the lauryl sulfate alone. Steiger (32) claimed it will protect the eye from harmful effects of other surfactants as well. No proof has been offered by the manufacturer, but this author and others agree that Mayport 4C probably shows anti-irritant activity in certain cases.

USE OF ANTI-IRRITANTS IN COSMETIC FORMULATING 337 Mineral Oils An exceptionally well controlled study by Hoekstra and Phillips (33) showed that certain mineral oil fractions are highly irritating when ap- plied topically to guinea pigs. All aromatic fractions caused problems mid-range parafiSnic material (b.p. 322 333øC) was the worst of the nonaromatic fractions. Mixing these with high boiling (over 402øC) fractions reduced irritation to zero, showing the dramatic anti-irritant activity of these high boiling point fractions. Rieger and Battista (34) reported that skin irritation [rom products containing combinations of light mineral oil with sodium lauryl sulfate, amine soaps or nonionic wetting agents can be alleviated by switching to a heavier grade mineral oil. Mirahogs Miranol 'C2M Concentration is a patented (35) lauroylcycloim- idinium amphoteric surfactant (Miranol Chemical Co. Inc.) which ap- parently reduces eye irritation by directly complexing certain irritants. For example, Miranol 2MCA Modified (36), an equimolar complex of Miranol C2M with sulfated lauryl alcohol, is completely nonirritating to the eyes, according to data published by the manufacturer. It was shown earlier in this paper that 0.14% C2M reduced eye irritation of an aerosol cologne to one-third and that of a highly mentholated (0.7% menthol) alcoholic product to zero. Miranol C2M was not particularly effective as the sole anti-irritant in an antiperspirant but did further reduce total eye irritation somewhat when used as an "auxiliary" anti -irritant. Myristyl Lactate This ester reportedly is useful at a level of 0.25% in alcoholic body rubs to reduce stinging. Similarly, it can be used in alcoholic after- shaves. However, when added at a level of 5% to an alcoholic anti- perspirant, it significantly raised eye irritation. Polypropylene Glycol The P 2000 grade (Dow Chemical Co.) of polypropylene glycol re- duced eye irritation and completely eliminated skin irritation in colognes, as described in the preceding pages.