638 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS !•vlOLL I ENT PEG 2_00 iV•(3NO OLL:"t--•7'oe o O--• EVALUATION IN ]•'ULSION BASE #I•-.•.• --8--/ RATE ALL QUALITIES ON 1-5 SCALE (remarks in parenthesis - 1/3/5 SLIP (slight/medium/much) TEX•RE of Cream (light/mediu•hea•) DESCRIBE IN lt'ORDS (thin•pasty, lardy, etc.)•½, "BK•&K" QUALI• (water/no change/oily) "ABSORPTION" TIME (short/medium/prolonged) G•NGE IN TEX•RE (beco nes lighter/no chavie•eavier) [ LUBRIC•T QUALITIES (tacky/drags/"rolls") •sc• I• •'o•os (w•xr, •=dr, et•.) •,•,•,• C) lEND FEEL• (Skin-Feel after complete Dry-Out) SHOO•INESS (poor/good/velvety ri•) FRICTION (tacky/skids/drag/sl .drag/slip) OILINESS (dry/waxy/oily) MOISTNESS (dry/neutral/dewy) DESCRIBE IN I•'ORDS (raspy, Figure 1. Typical work sheet ranking were complete, the identity of emollients being tested in that particular series was revealed to the evaluator. All emollients were tested in a base chosen with several specific pur- poses in mind: First, we wanted a typical cosmetic formula familiar to most cosmetic chemists. In an earlier test series, it was found that per- sons asked to evaluate emollients did so with considerably better discern-

EMOLLIENCY AND CHEMICAL STRUCTURE 639 ment if these were incorporated in a typical cream or lotion, rather than trying to feel them "pure." The second requirement of the base formula was that it be stable, with emollient content as high (37%) as practicable, so that the primary feel would be that of the emollient under test. Deliberate use was made of a TEA-stearate soap emulsifier system containing excess stearic acid to provide a "background" raspiness and drag which each emollient had to "overcome" before it could score well. Additional emulsion stability was provided by a generous amount of glyceryl monostearate, to insure that we would not obtain mixed (O/W -]- W/O or O/W/O) emulsions, which have a peculiar skin feel all of their own. Table II shows the evaluation of a Control Lotion, where water was substituted for the 7% emollient used in all other tests. This table also shows details of the numerical rating system used to determine the Skin Table II Control Lotion (No Emollient) Viscosity (25øC) = 912 cps Oil phase 4.0 % Glyceryl monostearate (pure) 3.0 Stearic acid XXX Water phase 4.0 Propylene glycol 0.5 Triethanolamine 0.4 Sodium lauryl sulfate 88.1 Water 100.0% Initial Slip = 4.0 (Scale 1-5 = slight to much slip) End Feel = 10.5 (Skin Feel after complete dry-out, the summation of four factors, each judged on a 1-5 scale. Total End Feel scale is therefore 4-20). End Feel Ratings 1 2 3 4 5 Smoothness 2.5 Poor Fair Good Smooth Friction 3.0 Tacky Skids Drag S1. drag Oiliness 3.0 Dry Dry/waxy Waxy Oily/waxy Moistness 2.0 Very dry S1. dry Neutral Sl. moist = 10.5 Velvety rich Slips Oily Dewy Skin Feel Index (SFI) = 4.0/10.5