86 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS monas aeruginosa is particularly resistant to many antimicrobial agents and probably represents one of the greatest challenges to preservatives. Preservatives function in cosmetic products to insure that they remain free from bacteria and molds. DMDM Hydantoin has been found to fulfill many of the microbiological, technical and toxicological requirements of a cosmetic preservative. No preservative, however, should ever be chosen without practical testing in the formulation. EXPERIMENTAL FORMULATION PROCEDURE Nineteen samples were prepared for preservative challenge testing. Actual formula- tions made and tested are tabulated in Tables I through IV. DMDM Hydantoin plus Table I Lotion Shampoo Formulas Formula No. 1 2 3 4 5 Ingredients, % Water 63.72 63.55 63.55 63.70 63.65 Trisodium HEDTA 0.10 Same Same Same Same Glycol Stearate 1.50 Same Same Same Same Cocamide DEA 3.00 Same Same Same Same Quaternium-19 0.75 Same Same Same Same TEA Lauryl Sulfate 30.00 Same Same Same Same Hydrolyzed Animal Protein 0.20 Same Same Same Same Fragrance 0.50 Same Same Same Same D & C Yellow No. 10 0.10 Same Same Same Same Methylparaben 0.10 -- -- -- 0.10 Propylparaben 0.03 -- -- -- 0.10 Quaternium-15 - 0.30 - - - DMDM tiydantoin -- -- 0.30 0.15 -- Total 100.00 100.00 100.00 100.00 100.00 Table II Liquid Hair Conditioner Formulas Formula No. 6 7 8 9 Ingredients, % Water 93.39 93.37 93.37 93.37 Stearyl Alcohol 1.80 Same Same Same Glyceryl Stearate 0.90 Same Same Same Petrolatum 1.80 Same Same Same Cetrimonium Chloride 1.25 Same Same Same Hydrolyzed Animal Protein 0.33 Same Same Same Fragrance 0.30 Same Same Same D & C Yellow No. 10 0.10 Same Same Same Methylparaben 0.10 -- -- -- Propylparaben 0.03 -- -- -- Quaternium-15 - •0.15 - - DMDM Hydantoin -- -- 0.15 0.15 Total 100.00 100.00 100.00 100.00

DMDM HYDANTOIN AS A COSMETIC PRESERVATIVE Table III Henna Cream Conditioner Formula No. 10 11 12 13 14 Water 46.20 46.50 46.55 46.45 46.20 Corn Oil (BHT/BHA) 0.30 Same Same Same Same Octoxynol-9 1.00 Same Same Same Same Sodium Chloride 0.60 Same Same Same Same Dimethyl Amino Propyl Lanolin Plus Amide Dietho-Sulfate Quaternium 1.20 Same Same Same Same Stearalkonium Chloride 2.00 Same Same Same Same Cetyl Lactate 3.00 Same Same Same Same Stearamine Oxide 3.50 Same Same Same Same Stearamidopropyl Dimethyl Amine 3.50 Same Same Same Same Laureth-23 5.00 Same Same Same Same Lanolin 2.00 Same Same Same Same Stearyl & Fatty Alcohols 12.00 Same Same Same Same Hydrolyzed Animal Protein 18.10 Same Same Same Same Henna--Neutral 0.10 Same Same Same Same Acetamide MEA 1.00 Same Same Same Same Methylparaben -- 0.10 -- -- -- Propylparaben -- 0.10 -- -- -- Quaternium-15 -- - 0.15 -- -- DMDM Hydantoin -- -- -- 0.25 ,0.50 Total 99.50 100.00 100.00 100.00 100.00 Table IV Hand Cream Formulas Formula No. 15 16 17 18 19 Ingredients, % Water 74.16 73.96 74.01 73.96 73.76 Lanolin 0.90 Same Same Same Same Lanolin Alcohol 0.90 Same Same Same Same Stearyl + Fatty Alcohol 4.30 Same Same Same Same Stearic Acid 2.60 Same Same Same Same Silicone Oil 1.00 Same Same Same Same Butyl Stearate 10.00 Same Same Same Same Jojoba Oil 0.50 Same Same Same Same Carbomer 934 0.22 Same Same Same Same Propylene Glycol 2.00 Same Same Same Same Dioctyl Sodiumsulfosuccinate 0.16 Same Same Same Same Allantoin 0.10 Same Same Same Same PCA 0.10 Same Same Same Same Panthenol 0.10 Same Same Same Same Triethanol Amine 0.26 Same Same Same Same Hydrolyzed Animal Protein 2.70 Same Same Same Same Methylparaben -- 0.10 -- -- -- Propylparaben -- 0.10 -- -- -- Quaternium-15 - - o. 15 - - DMDM Hydantoin -- -- -- 0.20 0.40 Total 100.00 100.00 100.00 100.00 100.00