IRRITANCY PATCH TEST COMPARISON 61 METHOD Patches dosed with test materials were applied laterally between the shoulder blades on the upper back, but not directly over the spine. Each type of patch was placed in a sepa- rate row. Test samples were added in the same sequence according to Figure 6. Test and control materials were applied to each patch in 20 μl. Patches were applied for approximately a 24-h period, then removed and discarded by the dermatologist approxi- mately 2 h before grading. After an evaluation, materials were reapplied to their assigned sites. These procedures were performed daily for 11 d, with fi nal evaluations performed after the fi nal patch removal on day 12. All induction patches were applied to the same sites, unless the cumulative grade of reac- tion was more than three or the adhesive necessitated removal. Figure 5. Webril semiocclusive. Table I Main Ingredients of the Three Test Materials Cream Lotion Bath cream Water Water Water Glycerine Glycerine Sodium benzoate Cetyl alcohol Cetyl alcohol Cocamidopropyl betaine Cocoglycerides Glycine soja oil Sodium laureth sulfate Glycine soja oil Helianthus annuus seed oil Sodium lauroamphoacetate Helianthus annuus seed oil Zea mays starch Polysorbate 20 Dimethicone Dimethicone Polyethylene glycol-150 distearate Zea mays starch Phenoxyethanol Citric acid Potassium cetyl phosphate Ethylhexylglycerin Hydrogenated palm glycerides Potassium cetyl phosphate

JOURNAL OF COSMETIC SCIENCE 62 Reactions to the test materials were scored using a combination of the grading scales (Tables II and III). The actual patch test scores were the combination of a numerical and/or letter score con- sistent with the defi nitions given in the scoring scale. Scores containing letter grades were converted into numerical equivalents as follows: A = 0, B = 1, C = 2, and D, E, and F = 3. These equivalents were considered comparable with any numerical score. STATISTICS To obtain classifi cations of the test materials, subject scores were added for each test site. Berger and Bowman established a standardized interpretation system for base (n = 10) irritation scores during induction at 14 d (5). This system was adjusted proportionally for Figure 6. Sample adding sequence.