HEMP-SEED AND OLIVE OILS 237 preliminary runs were carried out to obtain a sprayable 0/W emulsion whose pH was skin-compatible and that had an acceptable consistency and texture. The emulsion was modified by reducing the amount of Pemulen TR-1 and of 18% NaOH aqueous solu­ tion, as the initial cream was too thick and had a basic pH. NaOH aqueous solution was added slowly, and the pH was monitored to determine the minimum amount necessary to neutralize the system. This emulsion had acceptable rheological behavior (pseudo­ plastic with no hysteresis areas) and acceptable viscosity and pH. It was therefore chosen as the basic formulation from which to prepare some systems. Each emulsion was prepared with both hemp-seed and olive oils. The systems were characterized by evalu­ ating their stability, pH, apparent viscosity (at 5 s- 1 ), and rheological behavior, as described above. Each emulsion was then centrifuged at 3000 rpm for 60 minutes, and checked for any outcrop or phase separation every 10 minutes. The test was repeated at 4000 rpm. To verify the sprayability of the emulsions, an aliquot of each formulation was placed in a pump supply device. The product was then sprayed onto a sheet of glass, and uniformity of distribution was checked visually. All emulsions were also examined through an optical microscope. PREPARATION OF EMULSIONS WITH VEGETABLE OILS FOR USE AS FACIAL MOISTURIZING CREAMS These emulsions were obtained after a series of systems had been tested to determine the best systems. The best emulsions were obtained with the following emulsifiers: PEG- 4-olivate (Olivem 700®), cetearyl alcohol/cetearyl glucoside (Montanov 68EC®), C 14- 22 alkylalcohol/C 12-20 alkylglucoside (Montanov L®), polyglyceryl-3-methylglucose distearate (Tego Care®), sucrose tristearate or palmitate (sucroesters DUB SE® 3S and 15P), and sucrose mono (or di)stearate (or palmitate) (sucroesters SP® 30 and 50). These systems were characterized with the same methods previously described. Face cream 9. This emulsion was prepared with the cold-hot technique: the lipid phase (Olivem 700®, dimethicone, hemp-seed and olive oils, Finsolv TN®, cetearyl alcohol and glyceryl monostearate with the addition of Eurol BT®) was heated under mild stirring until complete homogenization. The aqueous phase (hydrolyzed milk protein, Hamamelis distillate, and filtered water) was prepared and slowly added to the hot lipid phase under homogenization at 11000 rpm. The homogenization was continued until the correct viscosity was achieved. The emulsion was cooled to room temperature under mechanical stirring at 100 rpm. Ten milliliters of an aqueous solution of Kathon CG® and Gram 1 ® were added to the emulsion at 25-30°C. Sepigel 305® was added, as rheological modifier, at room temperature, homogenizing at 11000 rpm for a few minutes. An alternative to this face cream was produced by adding Proteol OAT® as secondary emulsifier (Face cream 9B). Face cream 10. The emulsion was prepared with the hot technique. The lipid phase (Montanov 68EC® or Montanov L®, dimethicone, hemp-seed and olive oils, Finsolv TN®, and Eurol BT® was heated to 80°C, under mild stirring until uniformity was achieved. The aqueous phase (Hamamelis distillate and filtered water) was heated to 80°C and slowly added to the aqueous phase, homogenizing by Ultra Turrax T25 at 11000 rpm. The homogenization continued until the desired viscosity was achieved. The emulsion was cooled to room temperature, while being stirred mechanically at 100 rpm. Gram 1 ® , Kathon CG®, and Sepigel 305® were added at 25°C as for face cream 9. Face cream 11. The lipid phase (Tego Care, dimethicone, hemp-seed and olive oils,

238 JOURNAL OF COSMETIC SCIENCE Finsolv TN®, and Eurol BT®) was completely melted at about 50°C. The aqueous phase (Hamamelis distillate and filtered water) was heated to 50°C. The hot aqueous phase was then slowly added to the lipid phase under homogenization, the emulsion was cooled, and the preservatives added. Sepigel 305® was added to the emulsion to increase its viscosity. This formulation could also be used as a fluid body cream, omitting the Sepigel 305®. Face cream 12. The emulsion was prepared using, as emulsifiers, sucrose stearate or palmitate some runs were first made to determine the correct percentage of the emul­ sifiers and the best preparation technique. In the first run the two emulsifiers were both dispersed in the lipid phase, but the result was not satisfactory. The more lipophilic sucroester (DUB SE® 3S) was thus dispersed in the lipid phase while the more hydro­ philic one (DUB SE® 15P) was dispersed in the aqueous phase. This adjustment pro­ duced a homogeneous system with optimal viscosity. Following this method, the emulsifier DUB SE® 15P and Harnarnelis distillate were dispersed in warm water. The mixture was homogenized at 11000 rpm for one minute. The lipid phase (DUB SE® 3S, cetearyl alcohol, Finsolv TN®, olive oil, hemp-seed oil, dimethicone, and Eurol BT®) was slowly added to the aqueous phase under homogeni­ zation. The system was then cooled under stirring, and Kathan CG®, Gram 1 ® , and Sepigel 305® were added to the cold emulsion as described above. Face cream 13. Emulsion 13 was obtained employing the sucroesters SP 30 and SP 50 from Sistema as emulsifiers these and the Hamamelis distilled water were added to filtered water at 70°C, homogenizing the mixture at 11000 rpm for one minute. The lipid phase (Finsolv TN®, hemp-seed oil, olive oil, dimethicone, Eurol BT®, and cetearyl alcohol), at about 65°C, was slowly added to the aqueous phase under homogenization, and cooled under mechanical stirring at 100 rpm. The preservatives and Sepigel 305® were added to the system at room temperature, homogenizing until the desired consis­ tency was achieved. PERCUTANEOUS PENETRATION IN VITRO OF KATHON CG® FROM AN O/W EMULSION THROUGH PIG SKIN (16) Kathan CG®, a common preservative contained in many commercial formulations, was also present in all the emulsions prepared in this study. The compound possesses both antibacterial and antifungal properties and may also induce allergic reactions (17). Mutagenic activity has also been reported (18) on bacteria treated with a number of cosmetic products listing methylisothiazolinone and methylchloroisothiazolinone, the components of Kathan CG®, among their ingredients. Thus the release of this biocide from face cream 11 was investigated, and likewise the skin absorption of Kathan CG®, so as to determine the amount that crosses the skin and to evaluate any risk. Skin penetration studies play an essential role in optimizing formulation design for dermal and transdermal delivery. Experimental use of in vitro permeation techniques, such as Franz-type diffusion cells, is therefore very important. This system enables the kinetics of the uptake of different components and their diffusion from pharmaceutical or cos­ metic formulations (emulsions, gels, or creams) to be evaluated. The concentrations of such components in the deeper skin layers may also be determined by analyzing the receptor fluid. The Franz-cell system is widely used, being inexpensive, quick, and reproducible (16,19). Pig skin is suitable for in vitro dermal penetration studies, and the