292 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Table I Ingredient Listing Product A Product B Product C Product D Product E Product F Formula is proprietary to Colgate-Palmolive Formula is proprietary to Colgate-Palmolive Active ingredients: triclosan, sodium cocoyl isethionate, sodium laureth sulfate, ammonium sulfate, cocamidopropyl betaine, glycol stearate, fragrance, potassium chloride, cyclomethicone, polyquaternium-10, DMDM hydantoin, trisodium EDTA, trisodium EHDP, BHT Active ingredients: triclosan, water, sodium C14-16 olefin sulfonate, lauramide DEA, glycol stearate, silk peptide, hydrolyzed silk protein, cocamidopropyl betaine, polyquaternium-7, aloe vera gel, glycerin, tetrasodium EDTA, sodium chloride, DMDM hydantoin, citric acid, fragrance, yellow 5, red 33, red 40 Active ingredients: triclosan, water, sodium C14-16 olefin sulfonate, lauramide DEA, silk peptide, hydrolyzed silk protein, cocamidopropyl betaine, polyquaternium-7, aloe vera gel, glycerin, tetrasodium EDTA, sodium chloride, DMDM hydantoin, citric acid, fragrance, yellow 5, red 33, red 40 Active ingredients: triclosan, water, sodium lauryl sulfate, sodium laureth sulfate, sodium sulfate, lauramide DEA, cocamidopropyl betaine, fragrance, DMDM hydantoin, citric acid, tetrasodium EDTA, FD&C red 4, FD&C yellow 5 denaturation and produced similar results, although each method had its own advan- tages and disadvantages. We know from other work within our group that the irritation potential of certain combinations of surfactants can actually be less than that of the individuals surfactants (9). This is presumably due to mutual interactions between the surfactants making them less available to interact with the skin. Limited knowledge existed as to the effect of surfactant combinations on the in vitro screening tests and was available only for binary surfactant systems (10). Thus, this study was undertaken to extend the use of these screening tests to fully formulated products, in particular antibacterial liquid soaps. METHODS PRODUCTS TESTED Six products were chosen for mildness evaluation during these studies. All of the products were antibacterial liquid soaps. Four of these products were chosen because Table II Summary of In Vitro Results Product Collagen swelling (%) pH rise (%) Zein test (%) Total in vitro (%) A 34 23 31 88 B 29 29 25 83 C 39 48 17 104 D 38 42 30 110 E 36 42 34 112 F 61 5O 16 127 The SLS scores for the in vitro tests are as follows: collagen swelling: 9.44 unit increase pH rise: 1.70 unit increase zein test: 21.0 mg increase in solubilized zein/ml

EVALUATING IRRITATION POTENTIAL 293 Table III Summary of In Vivo Results Product Irritation (%) A 74 B 91 C 110 D 150 E 170 F 290 Results are expressed as a percentage of the mild control. they ranged from the mild to the extremely irritating. The formulas of two of the products are proprietary to Colgate-Palmolive. Table I lists the ingredients of the test products. 250 • 200 l o 150 .•.• lOO ß ß ß r =0.92 p = 0.01 I I I I I I I 25 30 35 40 45 50 55 60 65 Collagen Swelling (% of 1% SLS) Figure 1. Correlation between the effect of antibacterial liquid soaps on collagen swelling, expressed as a percentage of the effect of 1% SLS, and on the in vivo results, expressed as a percentage of the effect of the mild control.