WATER-SOLUBLE MUCILAGE IN A MOISTURE MASK 15 8O 7O • 50 o 40 m 30 •20 10 ß ß • ß ß ß X 0 0 X X ß 10 20 30 40 50 60 70 Time (min) Figure 3. Changes of capacitance increase ratio with time after applying moisture mask containing different concentrations of Monostroma nitidium aqueous extract and 1% hydroxyethyl cellulose measured at 23 ø + 0.5øC, RH 68.5%. •, 2.0% extract + 1.0% HEC. I, 1.5% extract + 1.0% HEC. ', 1.0% extract + 1.0% HEC. ¸, 0.5% extract + 1.0% HEC. x, 1.0% HEC. humectant or those containing 1% extract plus 1% MC. The electrical capacitance increase ratio increased to 57%-68%, then decreased over time. Electrical capacitance increase ratios after 60 min were between 59% and 45%. FILM-FORMATION TIME Results in Table III show that film-formation time for those moisture masks containing 1% HEC and different concentrations of the extract decreased from 14.08 min to 12.05 min with increasing concentration of the extract from 0.25% to 2%, respectively. For those moisture masks containing 2% HEC + 5% humectant and 2% MC + 5% hu- mectant, the film formation times were shorter than for their counterparts using 1% extract to replace 1% HEC and 5 % humectant or 1% MC and 5 % humectant and were ranged between 12.66 and 13.16 min vs between 13.25 and 13.08 min. SAFETY OF MOISTURE MASKS Table III shows the effect of adding different types and concentrations of thickening agents, with or without 5% humectant, on the pH and safety (Draize score) of moisture masks. The Draize scores of all moisture masks studied were zero. The results indicated that moisture masks containing hydroxyethyl cellulose, methyl cellulose, or &lonostroma niticliem mucilages resulted in no erythema on shaved rabbit skin. The pH values of those

16 JOURNAL OF COSMETIC SCIENCE 70 60 50 40 30 20 10 0 10 20 30 40 50 60 70 Time (rain) Figure 4. Changes of capacitance increase ratio with time after applying moisture mask containing different types and concentrations of thickening agents measured at 23 ø + 0.5øC, RH 68.5%. HEC: hydroxyethyl cellulose. MC: methyl cellulose. Extract: Monostroma nitidium aqueous extract. •, 2.0% HEC + 5% humectant. [•, 2.0% MC + 5% humectant. /N, 1.0% HEC + 1.0% extract. C), 1.0% MC + 1.0% extract. Table III Film Formation Time, pH, and Draize Scores of Moisture Masks Containing Different Types and Concentrations of Thickening Agents Measured at 23 ø _+ 0.5øC, RH 68.5% Film-formation time (min) pH Draize score 2.0% HEC + 5.0% humectant 2.0% MC + 5.0% humectant 1.0% HEC + 1.0% extract 1.0% MC + 1.0% extract 1.0% HEC + 2.0% extract 1.0% HEC + 1.5% extract 1.0% HEC + 0.5% extract 1.0% HEC + 0.25% extract 12.66 6.61 0 13.16 6.54 0 13.08 7.39 0 13.25 7.30 0 12.05 7.50 0 12.42 0 13.50 7.26 0 14.08 7.05 0 HEC, MC, and extract are the same in Table II. moisture masks ranged between 6.54 and 7.50 and were slightly higher than the normal pH of human skin. STORAGE STABILITY Changes in the apparent viscosity of moisture masks during storage at 4øC were used as an index of storage stability. Results in Figure 5 show that the apparent viscosity of