14 JOURNAL OF COSMETIC SCIENCE Table II Consistency Index (k), Flow Behavior Index (n) of Power Law Model and L, a, b Values of Moisture Masks Containing Different Types and Concentrations of Thickening Agents at 25 ø _+ 0.2øC n k L a b 2.0% HEC + 5.0% humectant 0.271 87.61 5.54 1.08 -2.79 2.0% MC + 5.0% humectant 0.466 39.86 12.47 1.23 -6.02 1.0% HEC + 1.0% extract 0.461 21.63 15.39 -0.21 -3.00 1.0% MC + 1.0% extract 0.510 19.10 15.18 -0.58 -2.81 1.0% HEC + 2.0% extract 0.296 38.31 28.21 -2.61 4.96 1.0% HEC + 1.5% extract 18.47 -1.24 -2.85 1.0% HEC + 0.5% extract 0.548 10.65 9.21 0.68 -3.46 1.0% HEC + 0.25% extract 0.597 7.65 7.25 1.25 -3.77 n and k were calculated from Figures 1 and 2. HEC: hydroxyethyl cellulose. MC: methyl cellulose. Extract: water-soluble mucilage of B4o•stroma •tidium. respectively. The flow consistence indexes of moisture masks containing 1% extract and 1% HEC and 1% MC were 21.63 and 19.10, respectively. For those containing 1% HEC and 2%, 0.5%, and 0.25% extract the indexes were 38.31, 10.65, and 7.65, respectively. COLOR OF MOISTURE MASKS The L, a, and b values of moisture masks containing different types and concentrations of thickening agents are also listed in Table II. The L values of moisture masks con- taining 1% HEC and different concentrations of the extract increased from 7.25 to 28.21 with increasing concentration from 0.25% to 2.0% of the extract. The L values were 5.54 and 12.47 for those masks containing 2% HEC + 5% humectant and 2% MC + 5% humectant, respectively. The a values of moisture masks containing 1% HEC and different concentrations of the extract decreased in the order of increasing concentration of the extract, the a values ranging between 1.25 and -2.61. The a values of moisture masks containing 2% HEC + 5% humectant and 2% MC + 5% humectant were 1.08 and 1.23, respectively. The b values of moisture masks containing 1% HEC and different concentrations of the extract increased from -3.77 to 4.96 with increasing concentration of the extract. The b values of moisture masks containing 2% HEC + 5 % humectant and 2% MC + 5% humectant were -2.79 and -6.02, respectively. EFFECT ON WATER-HOLDING CAPACITY OF MOISTURE MASKS Figures 3 and 4 show the changes in the electrical capacitance increase ratio over time after applying moisture masks containing different types and concentrations of thick- ening agents with (control) or without 5% 1,3-butadiene (humectant) at 23 ø + 0.5øC and RH 65% + 5%. Results in Figure 3 show that after applying moisture masks the electrical capacitance increase ratio increased with increasing concentration of the ex- tract. The electrical capacitance increase ratio increased to 57%-68%, then decreased over time. Electrical capacitance increase ratios after 60 min were between 59% and 42%. Results in Figure 4 show that the electrical capacitance increase ratios of a moisture mask containing 2% HEC and 5% humectant were higher than that contain- ing 1% HEC plus 1% extract, which was close to those containing 2% MC and 5%

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