290 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Table II Classification of the Surfactant Lacking the Function of Gel Formation Trade Name Appearance X-Ray Surfactant D•ffracrion Common Name RT lOB Pattern d• Spacing d: d_,/d, G-di-nC8 t Glycerol dioctanoate L 0.58 I 24.2 G-tri-nC• t Glycero[ trioctanoate L 0.33 I 28.0 G-mono-brCa r Gls, cerol mono 2- L 1.24 I 28.5 ethylhexanoate G-d•-brC8 t Glycerol di-2- L 0.6l N -- ethylhexanoate G-tri-brC• r Glycerol rri-2- L 0.35 N -- ethylhexanoate DIG-MO" Diglycerol monooleate L 0.80 I 38.2 DIG-TRO" Diglycerol trioleate L 0.26 I 29.3 DIG-TEO a Diglycerol tetraoleate L 0.17 I 27.7 TENOS ©• Gtycerol monostearate S 0.64 C 58.7 SPAN © 85 • Sorbitan trtoleate L 0.31 C 29.6 Nikkol ©z Batylalcohol S 0.23 C 28.0 GM- 181S monoisostearate Hostaphat ©h Trioleyl phosphate L 0.23 I 32.2 KO-300 Emalex ©e Eths, le neglycol L 0.40 I 30.5 EG-O monooleate EG-OPG-O e Propyleneglycol L 0.38 I 27.4 monooleate EG-O 300 dio • Propyleneglycol L 0.54 I (-) 300 dioleate EG-O 503 • POE(3)oleylethel L 0.57 N -- Nikkol ©• MYO-2 POE(2)oleate L 0.53 N -- POEM ©c O- 105 POE(5)glycerol L 1.03 N -- monooleate (-) (-) (-) -- 86.6 (-) (-) (-) 5%6 44.5 (-) (-) (-) (-) (-) (-) (-) -- 2.27 (-) (-) (-) 2.01 1.59 (-) (-) (-) (-) •Taiyo Kagaku Co, Ltd. (62 Akahori, Yokkaichi, Mie, Japan). OKao Atlas Co., Lid (1-1 Kayaba, N•honbasM, Chuoku, Tokyo, Japan) CRiken Vitamin Oit Co, Ltd. (3-8-10 Nishikanda, Chiyodaku, Tokyo, Japan). dMatsumoto Trading Co., Ltd. (3-1 NihonbasMhoncho, Chuoku, Tokyo, Japan). •5 N•hon Emulsion Co., Ltd. (5-32-7 Minamt, Koenj•, Suginamiku, Tokyo, Japan). •Nippon Fine Chemical Co., Ltd. (4-4-26 Honzanminami, Higashinodaku, Kobe, Japan). "Nikko Chemicals Co., Ltd. (1-4-8 Bakurocho, Nihonbashi, Chuoku, Tokyo, Japan). hHoechst Dyestuffs & Chemicals Co., Ltd. (Frankfurt, Germany). indicates those surfactants which did not produce a suitable gel. The various physical properties of the gel which were evaluated are shown in Figs. 3 to 17 and Tables III to IV. GEL EMULSIFICATION METHOD Materials.' A standard gel was formulated with Sunsoft O-30B and an aqueous solution of monosodium L-glutamate monohydrate. Other surfactants used are shown in Table I. Squalane (special reagent grade) was used as the oil phase. For the formulation of the creams, materials readily available commercially were used.

WATER-IN-OIL EMULSIONS 291 METHOD When the various premade gels were dispersed in the oil phase and emulsified by adding the water phase, excellent w/o emulsions were obtained. The emulsification method may be schematically shown as follows: Oil phase -'- (Dispersion/Mixing) • (Emulsification) • (Cooling) • w/o Emulsions 7oøC Gel• Homogeniz•ng Mixer Water Phase or Homogeniz•ng Votator-Type w/o Creams Mixer Heat Exchanger In order to compare the properties of these w/o emulsions and/or creams with those of the gels initially used, the following measurements were carried out. a. Hardness.' Hardness of the creams was measured at 25øC using a Curd Tension Meter.* The diameter of the needle was 8 mm and the load was 200 g. b. Viscosity: Viscosity of the samples was measured using a B-type viscometer (at 30øC) and a Ferranti-Shirley cone and plate viscometer-• (at 25øC, upper viscosity at the maximum rpm of 100 and a sweep time of 10 sec using M-cone). c. Emulsion Particles: These were determined in a manner previously described. d. Stability: The stability of the gels and w/o emulsions (or creams) stored for a month at 0øC, 25øC, 37øC was observed. These results are shown in Tables V and VI and Figs. 18 to 20. Figure 3. Typical small-angle diffracuon pattern ofsurfactant, Sunsoft O-30B *Iio Denki, 2-27 Yoyogi, Shibuyaku, Tokyo, Japan. -I'Ferranti Ltd., Maston, Manchester 10.