Table X pH and Viscosity, Indicative of the Influence of the Vegetable Oils on the Emulsions, Before and After Heating Eye gel-emulsion Eye gel-emulsion Eye gel-emulsion Eye gel-emulsion Eye gel-emulsion with extra-virgin with hemp-seed oil with hemp-seed oil with olive oil with olive oil olive oil (before heating) (after 1 h at 40 ° C) (before heating) (after 1 h at 40 ° C) (before heating) Viscosity at 8150 7500 9400 8550 9800 5 s- 1 (mPa s) pH 4.80 4.75 5.15 5.15 5.10 Eye gel-emulsion with extra-virgin olive oil (after 1 h at 40°C) 9800 4.97 ::r: t:d � ""O I C/) t:d t:d u z 0 - t:d 0 - r C/) N ,.j:::,-._ Vl

246 JOURNAL OF COSMETIC SCIENCE SPRA YABLE AFTER-SUN MILK The composition of the basic formulation chosen to prepare the sprayable emulsion was: vegetable oil (10%), 18% NaOH aqueous solution (0.27%), Pemulen TR-1 ® (0.10%), and water (89.63%). Table XI gives the compositions of five different formulations for sprayable after-sun milks Table XII shows their viscosity and pH characteristics. The viscosity range of these 0/W emulsions was typical of fluid systems, and their pH values were skin-compatible. All the after-sun emulsions considered showed a pseudoplastic trend with no hysteresis area and with a tendency to Newtonian flux. All proved to be sprayable and stable to centrifugation at 3000 rpm. Each of the surfactants employed was compatible with both the hemp-seed and the olive oil, except for the glucamate: emulsion 5 was found to be unstable. MOISTURIZING FACE CREAM Several trials were carried before the most suitable formulations were determined. The choice of surfactant and of rheological modifiers greatly influenced the overall quality of the system. Moreover, it was found to be quite difficult to prepare emulsions containing olive oil and/or hemp-seed oil. Tables XIII, XIV, XV, XVI, and XVII report the compositions of some moisturizing face creams incorporating olive oil and hemp-seed oil and employing five different surfactants. These five systems had high stability, suitable subjective feel on the skin, and thixotropic pseudoplastic flux. CHARACTERIZATION OF FACE CREAMS 9A AND 9B Emulsions 9A and 9B proved to be stable after centrifugation at 4000 rpm for 10 minutes, both before and after heating (40°C for 24 hours). Table XVIII shows the viscosity and pH values, as the means of three measurements. Both emulsions showed a pseudoplastic behavior with a small hysteresis area. As an example, Figure 4 shows the rheological trend of emulsion 9B before and after heating at 40°C for 24 hours. Table XI Percentage Composition of Sprayable After-Sun Milks Containing the Oils Studied Emulsion 4 Emulsion 5 Emulsion 6 Emulsion 7 Emulsion 8 Ingredients (w/w%) (w/w%) (w/w%) (w/w%) (w/w%) Vegetable oil 7.0 7.0 7.0 7.0 7.0 Tween 20® 0.50 Tween 40® 0.50 NaOH 18% 0.27 0.27 0.27 0.27 0.27 Pemulen TR-1 ® 0.10 0.10 0.20 0.10 0.10 Cremophor RH40® 0.50 LRI® 0.60 Glucamate 0.50 Methyl glucose dioleate 0.20 Water 92.13 92.13 92.03 92.03 91.93