PREPARATION AND EVALUATION OF CREAM MASK 457 Figure 2. Cell proliferation (A), moisture retention (B), and tyrosinase inhibitory activities (C) of biological active components in seaweed extracts. Value represents mean ± SEM (n = 5). *p 0.05, **p 0.01 versus control of each group. extracts, the pH of the SCM slightly decreased from 6.3 to 6.1. It was reported that the normal pH range of cosmetics is between 3.0 and 9.0 (42). Therefore, the mixture of seaweed extracts was suitable for cosmetic products. The refractive index of the cream mask with and without the mixture of seaweed extracts was 1.47 and 1.50, respectively. The viscosity of SCM [89.1 centipoises (Cp)] was lower than that of CCM (110.3 Cp), and this result was due to the lower viscosity of the mixture itself. Spread ability test is an evaluation to determine the ability of the cream to spread. The spread area of 25–49 cm2 shows that semisolid textures are convenient in use (43). Spread ability of SCM was higher than that of control cream. It was suitable with suggestion of Hanum and Laila (21), in which the low spread ability was related to the high viscosity of the mask if the given pressure was applied equally in each gel formula. The adhesiveness test was con- ducted to investigate the cosmetic product ability to attach on the skin. If the formula attached extensively, then the therapeutic effect given by the product will be prolonged because of the long contact time on the skin. There is no specifi c requirement regarding the adhesiveness of the semisolid product. However, the adhesiveness of the semisolid product is better more than 1 s (21). There was no observed difference in the adhesive ability between control and SCM. Because of the wide range of formulations, it is necessary to control microbiological growth in cosmetics. According to Asian guidelines on limits of contaminant for cosmetic, the total aerobic mesophilic microorganisms (bacteria, yeast, and molds) must be below 1,000 colony- forming unit/g. S. aureus, P. aeruginosa, and C. albicans must be absent in 0.1 g or 0.1 mL test

JOURNAL OF COSMETIC SCIENCE 458 sample. In this study, no specifi ed microorganisms were detected in both control cream and SCM (Table IV). In general, heavy metals are commonly found in seaweed because of the living habit. In our study, some heavy metals were found in the selected seaweeds. And according to Asian guidelines on limits of contaminant for cosmetic, the limit of arsenic, cadmium, lead, and mercury is 5, 20, and 1 ppm, respectively. We, therefore, detected the presence of those heavy metals in the cream masks. As shown in Table IV, there were no heavy metals in the cream mask products. Contact sensitivity to cosmetics is a common phenomenon for human skin. Patch test is a method used to determine whether a specifi c substance causes allergic infl ammation on a patient’s skin. To confi rm safety of the extracts for human skin, a patch test was evalu- ated on 20 female volunteers. When the 20 mg of mixture per test patch was applied, none of the 25 subjects developed erythema, cellular infi ltration, or vesicles (Table IV). Based on these results, we suggest that the mixture of seaweed extracts is safe and not irritating to normal human skin at tested doses. Collectively, our obtained results sug- gested that the physicochemical and microbiological properties of the cream mask from the mixture of seaweed extracts meet provisions of Circular No. 06/2011/TT-BYT dated January 25, 2011 of the Vietnam Ministry of Health, providing cosmetic management. A cream mask is one of the most gentle face masks made to remove dead cells while ton- ing and lifting skin. They typically contain ingredients such as hyaluronic acid to provide Table IV Physical, Physicochemical, Chemical, and Microbiological Properties of CCM and SCM Parameters Test cream mask products CCM SCM Physical properties Organoleptic White Yellowish brown with a specifi c odor Homogeneity Homogen Homogen Physical stability at 10°C ± 2°C and 45°C ± 2°C Stable Stable pH 6.3 6.1 Viscosity 110.3 89.1 Refractive index 1.47 1.50 Spread ability (cm3) 10.2 24.2 Adhesive ability (second) 10.0 10.5 Irritation test Nonirritating Nonirritating Heavy metal Arsenic 1 1 Cadmium Nd Nd Mercury Nd Nd Lead 5 5 Microorganisms Total aerobic mesophilic microorganisms (bacteria, yeast, and molds) 10 10 S. aureus Nd Nd C. albicans Nd Nd P. aeruginosa Nd Nd Nd: not detected.