J. Cosmet. Sci., 66, 359–370 (November/December 2015) 359 Feasibility study of a cosmetic cream added with aqueous extract and oil from date (Phoenix dactylifera L.) fruit seed using experimental design FATMA LECHEB and SALEM BENAMARA, Research Center in Physicochemical Analysis, Bou-Ismail, 42004, Tipaza (F.L.), and Research Laboratory in Food Technology, Faculty of Engineering Sciences, University M’hamed Bougara, Boumerdès, 35000, Algeria (S.B.). Accepted for publication July 26, 2015. Synopsis This article reports on the feasibility study of a cosmetic cream added with aqueous extract and oil from date (Phoenix dactylifera L.) fruit seed using experimental design. First, the mixture design was applied to optimize the cosmetic formula. The responses (dependent variables) were the spreadability (YSp) and viscosity (YVis), the factors (independent variables) being the weight proportions of the fatty phase (X1), the aqueous date seed ex- tract (X2), and the beeswax (X3). Second, the cosmetic stability study was conducted by applying a full factorial design. Here, three responses were considered [spreadability (Sp), viscosity (Vis), and peroxide index (PI)], the independent variables being the concentration of the date seed oil (DSO) (x1), storage temperature (x2), and storage time (x3). Results showed that in the case of mixture design, the second-order polynomial equations correctly described experimental data. Globally, results show that there is a relatively wide composition range to ensure a suitable cosmetic cream from the point of view of Sp and Vis. Regarding the cosmetic stability, the storage time was found to be the most infl uential factor on both Vis and PI, which are considered here as indica- tors of physical and chemical stability of the emulsion, respectively. Finally, the elaborated and commercial cosmetics were compared in terms of pH, Sp, and centrifugation test (Ct). INTRODUCTION Numerous works are devoted to the valorization of date (Phoenix dactylifera L.) seeds (DS) under different forms: activated carbon (1), livestock feed (2), preparation of citric acid and proteins (3), and uses in traditional medicine (4), knowing their antimicrobial and antiviral properties (5). Address all correspondence to Salem Benamara at sbenamara2001@yahoo.fr. Presentation: The fi rst version of the content of this article was presented as oral communication at the 3rd International Conference on Mathematical Modeling in Physical Sciences, Madrid, Spain, August 28–31, 2014.

JOURNAL OF COSMETIC SCIENCE 360 Concerning the chemical composition of DS, other investigations revealed the presence of phenolic compounds (among others) (6) and fat (7). This last constituent contains various fatty acids, including linoleic acid and polyphenols whose concentration is higher than that of olive oil (8). This composition makes the DS oil and extracts the interesting in- gredients in cosmetic formulations, enhancing the oxidative stability (9) and skin protec- tion of the fi nal product (10). On the other hand, it was also underlined that the seed oil, as fatty acid–rich product, presents a high commercial value in cosmetics and others (11). Despite the absence of offi cial standard concerning the natural cosmetics (12), the devel- opment of phytochemical-rich products is characterized as a market tendency in cosmet- ics (13). In addition, the increased wariness toward modern cosmetics has stimulated renewed interest in herbal cosmetics (14,15). At the same time, various research works are devoted to this topic. Thus, Anchisi et al. (16) have studied the stability of new cos- metic formulations with vegetable extracts as functional agents and Papageorgiou et al. (17) have developed new cosmetic formulations by replacing chemical preservatives with extracts of Lonicera caprifoleum and Lonicera japonica in combination with different chemi- cals. Bowe (18) has reviewed the cosmetic benefi ts of some natural ingredients, including green tea for which the photoprotection against ultraviolet (UV)-induced DNA damage was underlined. For their part, Gilani et al. (19) have evaluated the antimicrobial activity of cream formulated with essential oil of Trachyspermum ammi. Categorized in the intersection between drugs and cosmetics, cosmeceutics are able to enhance, by external application, the beauty and health of skin (20). In fact, the tradi- tional use of plants against skin illness is an enough common practice in domestic medi- cine of lots of cultures (21). As underlined by these authors, there are no studies on traditional knowledge concerning cosmetic products, although the interest in natural and/or organic cosmetics has increased among the consumers (15). This article reports on the assay of obtaining and characterization of a cosmetic cream added with date (P. dactylifera) seed oil (DSO), by applying (i) mixture design for the optimal formulation and (ii) full factorial design for the stability study of the fi nal prod- uct. It has been already underlined that the use of an experimental design can signifi - cantly improve the development of cosmetic emulsions (22). Despite the absence of works about cosmetic formulation with DS derivatives, numerous authors suggest the possibility to incorporate DSO in cosmetics, based on its chemical composition and UV-protection abilities (23–26). Studying skin permeation of diclofe- nac, Kim et al. (27) have previously demonstrated the potent skin-permeation-enhancing effect of palmitic and oleic acids, two molecules also present in DS (23). In addition, the use of olive oil as oleaginous excipient in oral, topical, and parenteral solutions was re- ported (9), so this oil was used in this study as a component of the fatty phase of the in- vestigated cosmetic cream. MATERIALS AND METHODS INGREDIENTS Besides lecithin that was provided by the manufacturing unit of margarine “SOFARMA” in the Boumerdès area (40 km east of Algiers), other ingredients were either purchased