CHALLENGES TO SUNSCREEN EVALUATION 591 be extracted in mPF format and a different calculating template was needed to convert mPF values to transmittance values. The second part of this method is dedicated to the calculation of the actual UVAI/UV ratio and UVA category. This requires converting the transmittance average values for each wavelength to the absorbance average values using the following equation: A(λ) = -log T(λ). The index of UVA protection is calculated as the area per unit wavelength under the UVAI portion of a plot of absorbance, A(λ) versus wavelength, divided by the area per unit wavelength under the entire UV portion of the curve. The areas of the UVAI and UV sections of the curve are calculated according to these equations: O O O O O O O ³ ³ ³ ³ 400 400 400 400 340 340 290 290 ( ) ( ) ( )/ ( ) and ( ) ( ) ( )/ A d B d A d B d(O) The integrals in these formulas are calculated using Simpson’s rule for irregular areas, with the assumption that the biological action spectrum factor, B(λ), is equal to 1 for all wavelengths. The FDA is proposing that test results for each in vitro or in vivo test be categorized ac- cording to UVA rating categories (Table I). It is proposing that the overall UVA radiation category for use in product labeling be the lowest category determined by the in vitro and in vivo test results. Manufacturers of products that do not obtain a minimum UVA protec- tion either in vivo or in vitro, or who choose not to make UVA claims or run tests, are required to label the product “No UVA Protection.” Each overall UVA protection cate- gory corresponds to and (on product labeling) may be used with the graphical representa- tions in the form of solid “stars” illustrated in Table II. TEST ARTICLES Six commercial and two experimental test articles containing various sunscreen actives were utilized. Two experimental sunscreen prototypes contained bisoctrizole (USAN), bemotrizinol (USAN), avobenzone, and octocrylene. It should be noted that bisoctrizole and bemotrizinol are being evaluated by the FDA under TEA and are not permitted in the US at this time, but they are approved in the rest of the world. Experimental test articles: formulations and manufacturing procedures (A) Experimental sunscreen N (Table III) • Technical data: pH value = 5.0-6.0 viscosity (Brookfi eld DV-II + T-F @3rpm) = 130,000–190,000 cps. Table I UVA Rating Categories Category In vitro result In vivo result Low 0.20 to 0.39 2 to under 4 Medium 0.40 to 0.69 4 to under 8 High 0.70 to 0.95 8 to under 12 Highest Greater than 0.95 12 or more

JOURNAL OF COSMETIC SCIENCE 592 • Manufacturing procedure: In a suitable container, Part A ingredients are added and heated to 68°C–72°C. In a side container, ingredients of part B are premixed and heated to 68°C–72°C. When Part A and Part B reach the desired temperature, Part B is slowly added into Part A and mixed well and/or milled if desired. In a separate container, Part C is premixed until uniform. When the main batch is below 50°C, Part C is added and mixed well. Cooling of the batch continues. When the main batch is below 30°C, Part D is added and mixed until it is completely smooth and uniform. An increase of the shear may be necessary to overcome accumulation. Part E is premixed and added to the main batch with continuing mixing. The rest of the ingredients are added and mixed until uniform. Table II Graphical UVA Rating Based on Category Combined category rating Star rating Low œœœ Medium œœ High œ Highest  Table III Experimental Sunscreen N Part INCI-Name/USAN Supplier % w/w (as supplied) A Water q.s Disodium EDTA Fluka 0.10 PEG-8 Jeen International 1.00 Butylene glycol Fluka 2.50 B Dibutyl adipate Cognis 3.00 Steareth-2 Lipo 0.75 Steareth-20 Lipo 1.00 Isodecyl neopentanoate ISP 1.50 PEG-100 stearate Lipo 1.75 Cetearyl alcohol Croda 2.50 Bemotrizinole (USAN) Ciba 2.00 Octocrylene ISP 2.30 Avobenzone DSM Nutritional Products, Inc. 3.00 C12-15 alkyl benzoate Finitex 2.00 Isononyl isononanoate Alzo International, Inc. 1.50 Cetyl lactate Lipo 0.75 Diethylhexyl 2,6-naphthalate Symrise 1.75 Isopropyl myristate Cognis 1.50 C Water 20.00 Bisoctrizole (USAN) Ciba 12.00 Acrylates/C12-22 alkyl methacrylate copolymer ISP 1.00 D Sodium acrylates copolymer (and) hydrogenated polydecene (and) PPG-l trideceth-6 Ciba 0.80 E Cyclopentasiloxane (and) dimethiconol Dow Corning 0.80 Isododecane (and) dimethicone corsspolymer-3 Jeen International 0.36 F Phenoxyethanol (and) ethylhexylglycerin S&M 0.65 Fragrance q.s