108 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Table II Minimum Inhibitory Concentration (%) for Preservatives Effective in One or More Lotions Preservative Trade Name Chemical Name Anionic Lotion a Nonionic Lotion a Acid Alkaline Acid Alkaline Bronopol (Goldschmidt) Dehydroacetic acid (Gane's) Dioxin -• Giv-Gard DXN (Givaudan) DMDMH (Glyco) Dowicil 200 (Dow) Formaldehyde (Fisher) Hibitane (Imperial) MDMH (Glyco) Nipastat (Nipa) Noxyfiex (Geistlich} Ottasept (Ottawa) Phenonip (Nipa) Phenoxetol (Nipa) Phenyl c' hyl alcohol (IFF) Polycide A (Zwicker) Polynoxylin (Geistlieh) Sorbic acid (Pfizer) Omadine, Sodium (Old) 2-Bromo-2-nitropropane-1-3-diol 0.05 0.1D 0.1 0.1 •) 3-Acetyl-6-methyl-2H-pyran-2, 4 (3H)-dione 0.1 NT '0.2 NT 6-Acetoxy-2,4-dimethyl-m- dioxane Dimethylol dimethyl hydantoin Cis isomer of 1-(3-chloroallyl)- 3,5,7-triaza-l-azonia-adaman- tane chloride Formaldehyde solution, 40% Bis (p-chlorophenyldiguanido) hexane Monomethylol dimethyl hydantoin Nipa ester 82121-mixture of methyl, ethyl, propyl, butyl, benzyl parabens N-Methyl-N'-hydroxymethyl thiourea Parachlorometaxylenol Mixture of phenoxetol and parabens Ethylene glycol monophenyl ether 2-Phenylethanol Tris (2-hydroxyethyl) triazonium methyl carboxy phenolate Polynoxymethyleneurea 2,4-Hexadienoic acid Sodium pyridinethione 0.1 0.1 0.15 0.2 0.1 0.1 0.1 0.1 0.075 D 0.1 I} 0.1 0.1 0.05 0.05 0.075 0.675 0.1 0.1 0.1 0.1 0.2 0.2 0.5 0.5 0.225 0.3 0.3 0.3 0.25 0.2 0.5 0.2 0.5 0.38 0.5 0.5 0.5* 0.5 0.5 0.5 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.15 0.1 0.15 0.1 0.3 0.3 0.3 0.3 0.1 NT 0.15 NT C.I' 0. l 0.1' 0.1 • Symbols used: D = Discoloration NT: Not Tested * = Approximate MIC n: In- effective at the maximum concentration indicated.

PRESERVATIVE REQUIREMENTS OF O/W EMULSIONS Table III Minimum Inhibitory Concentrations (%) for Preservative Mixtures Effective in One or More Lotions 109 Preservative Mixture Trade Name Bronopo1-4- Omadlne, Sodium LMDMII -4- Omadine, Sodium MDMH q- Omadine, Sodium Bronopol q- Methylparaben (Mallinckrodt) + Propylparaben (Mallinckrodt) Formaldehyde q- Methylparaben q- Propylparaben Germall q- Methylparaben q- Propylparaben G•rmall q- Methylparaben q- Butylparaben Methylparaben q- Propylparaben Hibitane q- EDTA (Ciba-Geigy) Chemical Name Methyl p-hydroxy- benzoic acid Propyl p-hydroxy- benzoic acid Anionic Lotion a Nonionic Lotion a Acid Alkaline Acid Alkaline 0.1 •' 0.P 0.1 0.1 0.05 0.05 0.05 0.05 0.1' 0.1 * 0.1' 0.1 • 0.05 0.05 0.05 0.05 0.2* 0.2* 0.2* 0.2* 0.05 0.05 0.05 0.05 0.018 0.013 • 0.005 0.1 • 0.038 0.025 0.1 0.2 0.009 0.00e 0.025 0.05 0.013 0.018 0.038 0.038 0.05 0.075 0.15 0.15 0.013 0.018 0.038 0.038 0.38 0.5 0.5 0.5 0.15 0.2 0.2 0.2 0.038 0.05 0.05 0.05 0.5* 0.5* 0.5 0.5 0.1 0.1 0.1 0.1 0.02 0.02 0.02 0.02 0.15 0.2 0.2 0.2 0.038 0.05 0.05 0.05 0.1 0.1 0.1 0.1 0.05 0.05 0.05 0.05 Ethylene diamine- tetraacetic acid Vancide 89RE n-Trichloromethylthio- (Vanderbilt) q- 4-cyclohexene-l,2- dicarboximide 0.2 s 0.075 0.2 v 0. 2v Phenoxetol 1.0 0.375 1.0 1.0 Preservative 68 Halogenated aliphatic (Dutton & Reinisch) q- amide 0.13 0.19 0.25 0.19 Formaldehyde 0.013 0.019 0.025 0.019 Symbols used: * = Approximate MIC D = Discoloration S = Separation of emulsion V = Viscosity changes n: ineffective at the maximum concentration indicated. Test Procedures Preparation of Lotions Test lotions without preservatives were prepared and immediately refrig- erated to prevent spoilage. Preservatives were dissolved in water or ethanol,