MINERAL-ALGAL-BOTANICAL COMPLEX 29 extract is INCI-defined as "algae" (supplied by Henkel Corporation). "Desert plants" are Fenugreek, INCI-defined as "Trigonella Foenum-Graecum extract," and Jujube, INCI- defined as "Ziziyphus jujuba extract" (both botanical extracts supplied by Alban Muller International). Dead Sea Mineral Skin Osmoter TM is a highly concentrated aqueous solution extracted from the Dead Sea via a natural evaporation process developed by the Dead Sea Laboratories Ltd. This ingredient contains a high level of bivalent cations. The composition of this brine is presented in Table I. GROWTH OF DUNALIELLA SALINA AND HARVEST OF THE BIOMASS Innoculum of Dunaliella salina algae, type 19/31, was purchased from the Culture Collection of Algae and Protozoa (CCAP). The algae were cultivated in semicontinuous batches based on American Type Culture Collection (ATCC) DA medium No. 1174 (18). The biomass was harvested by continuous centrifugation, lyophilized (Labconco lyophilizer) in the presence of 0.01-0.2 % methyl paraben as a preservative, and crushed with a mortar and pestle. The crushed algal powder was utilized for biosorption tests. COSMETIC PREPARATIONS Two oil-in-water emulsions, textured as light cosmetic creams, were prepared and comparatively tested: (a) a moisturizing antiwrinkle base cream, serving as a control, and (b) the same moisturizing antiwrinkle base cream, enriched with 5% Triple D Com- plex TM. LASER PROFILOMETRIC TEST Each preparation was applied twice a day over a period of four weeks to 20 female volunteers, aged 22 to 63, average age above 36 years, on both right and left forearm. Half of the participants were categorized as having sensitive skin and the rest as having normal skin. At the beginning and end of the application period, silicone impressions were taken from the same area of skin on the right and left forearms. Twelve hours before the impressions were taken the participants were not permitted to apply cream or to use active washing substances. Each subject was acclimatized to room temperature 30 min- utes prior to the measurements. Structural changes of the epidermis were quantitatively classified with a computer-aided laser profilometric system according to ISO 4287/1 ("Surface roughness terminology"). Skin surface changes were evaluated by comparing Rz values, a roughness parameter of a surface profile, as measured by the silicone impression, before and following the skin treatments (15). Table I Typical Chemical Analysis of Mineral Skin Osmoter TM (INCI-listed as "Marls Sal & Aqua") Cation Mili-equivalent/1 Anion Mili-equivalent/1 Na + 107 C1- 9320 K + 37 SO4 -2 7 Ca 2+ 1850 Br- 150 Mg 2+ 7430 HCO3 2

30 JOURNAL OF COSMETIC SCIENCE SKIN HYDRATION TEST Skin surface hydration state was assessed by a skin capacitance-based instrument (cor- neometer CM 820, Courage & Khazaka GmbH). The measurements by the interdigital electrode indicate changes in skin capacitance due to variations in the moisture content of the stratum corneum (SC). Twenty female volunteers, aged between 22 and 63, applied the tested compositions to three different places on the lower arm. The mean value of the three obtained measurements was calculated. The measurements were taken immediately after application, after 8 hours, and after 12 hours. Untreated skin of the contralateral lower arm was used as a control. Subjects were acclimatized to an ambient temperature of 22øC and relative humidity of 60% for 45 minutes prior to the mea- surements. The recorded capacitance values were converted into arbitrary hydration units varying from 0-120 rcu (relative corneometer units) (16,17). BIOSORPTION EXPERIMENTS A series of incubations with 1 g of dry, crushed Dunaliella powder and 25 ml of Dead Sea concentrated brine (Mineral Skin OsmoterZM) was carried out in various combina- tions of brine pH, temperature, and exposure times. Algal biomass and brine were mixed and incubated in Erlenmeyer flasks, and mixed with an orbital shaker (EnvironShaker 3328 type, Lab-Line) or with a magnetic lab stirrer. The ratio of mineral biosorption to algal biomass was evaluated in correlation with the pH of the brine, temperature of the solution, and exposure time. After incubation, the brine was separated from the biomass by centrifugation (Sorval RC-58 centrifuge, 10 min, 24,000 g). Non-sorbed salt residues were removed from the algae by two consecutive washing cycles, each of 150 ml distilled water. The algal precipitate was lyophilized, and the dried biomass was digested overnight in 4% nitric acid. The concentrations of acid-soluble calcium, magnesium, and potassium in the biomass were measured by atomic absorption (Varian, type Spectra 10 AA). DESORPTION EXPERIMENTS Dunaliella salina biomass was saturated with minerals from Dead Sea Mineral Skin OsmoterZM brine under the optimal conditions found previously: pH 5-5.5, 15-minute exposure time, 33øC. The saturated biomass was washed twice with distilled water, and the slurry was kept at 4øC. Portions of the biomass were introduced into distilled water in a ratio of 0.5% dry weight to water, and exposed to an experimental design matrix of parameters. Design-Ease TM software was used for the experimental design and analysis (Stat-Ease Ltd. 1992, Minneapolis). Residual levels of minerals in the dry algal biomass were evaluated by atomic abosption. RESULTS SKIN ROUGHNESS EVALUATION The surface roughness of the skin was evaluated quantitatively by mean, standard