Cosmetics microemulsions

The development of cosmetic microemulsion cleansers with alkyl polyglycosides (APG) was described by Forster et al. [4]. This class of non-ionic surfactants has excellent environmental and skin compatibility. Cosmetic cleanser multicomponent systems are required to have good foaming and cleansing performance. Figure 8.3 shows a pseudo-ternary phase diagram of a five-component formulation. It consists of water, the oil dioctyl cyclohexane (DOCH), the non-ionic surfactant C12/14-APG, the anionic surfactant fatty alcohol ether sulphate (FAES) and the co-surfactant sorbitan monolaurate (SML). The phase diagram... 

Investigations have been reported in the form of composition trajectories in the condensed phase during evaporation, and a typical result is given in Fig. 4. The figure shows several trends of importance for a cosmetic microemulsion, which will be discussed after the information from the trajectories has been evaluated. 

Maillefer, S. Chambettaz, D. Franzke, M. Clear cosmetic microemulsions containing ethoxylated castor oil and an emulsifier with high NRU50 value for eliminating eye and skin irritation. Eur. Pat. Appl. EP 1559395, 2005 Chem. Abstr. 2005,143, 119091. 

The current or potential iadustrial appHcations of microemulsions iaclude metal working, catalysis, advanced ceramics processiag, production of nanostmctured materials (see Nanotechnology), dyeiag, agrochemicals, cosmetics, foods, pharmaceuticals, and biotechnology (9,12—18). Environmental and human-safety aspects of surfactants have begun to receive considerable attention (19—21). 

Microemulsions or solubilized or transparent systems are very important ia the marketing of cosmetic products to enhance consumer appeal (32,41). As a rule, large quantities of hydrophilic surfactants are required to effect solubilization. Alternatively, a combination of a solvent and a surfactant can provide a practical solution. In modem clear mouthwash preparations, for example, the flavoring oils are solubilized in part by the solvent (alcohol) and in part by the surfactants. The nature of solubilized systems is not clear. Under normal circumstances, microemulsions are stable and form spontaneously. Formation of a microemulsion requires Httle or no agitation. Microemulsions may become cloudy on beating or cooling, but clarity at intermediate temperatures is restored automatically. 

Emulsifiers are used in many technical applications. Emulsions of the oil-in-water and the water-in-oil type are produced on a large scale in the cosmetic industry. Other fields of employment are polymerization of monomers in emulsions and emulsification of oily and aqueous solutions in lubricants and cutting oils. In enhanced oil recovery dispersing of crude oil to emulsions or even microemulsions is the decisive step. 

Nakajima, H. (1997) Microemulsions in Cosmetics, (eds C. Solans and H. Kunieda) Industrial Applications of Microemulsions, V 66. Marcel Dekker, NewYork, pp. 175-197. 

Microemulsion is used as a special microreactor to limit the nano-sized particles growth. The shape of the microreactor depends on reaction conditions [9]. This method increases the homogeneity of the chemical composition at nano-level and facilitates the preparation of nano-particles with comparatively equal sizes [11]. The specific properties of the nano-particles make them suitable for microelectronics, ceramics, catalysis, medicine, cosmetics, as piezoelectric materials, conductors, etc. 

Microemulsion system applications span many areas including enhanced oil recovery, soil and aquifer decontamination and remediation, foods, pharmaceuticals (drug delivery systems), cosmetics, and pesticides [2,5,33,37,232,233]. Some of these are listed in Table 3.6. The widespread interest in microemulsions and use in these different industrial applications are based mainly on their high solubilization capac-... 

First a coarse O/W emulsion is prepared and, on heating, phase inversion occurs. After cooling down through the microemulsion zone, the finely dispersed nature of the microemulsion is partially retained and emulsions with drop sizes of about 100 nm result [28-30]. They show considerable long-term stability as a consequence of the Brownian motion of the oil droplets [31] and pump sprayable deodorants are one of the cosmetic products based on this technology. 

Amphiphilic lipopeptides with a hydrophobic paraffinic chain containing from 12 to 18 carbon atoms and a hydrophilic peptidic chain exhibit lyotropic meso-phases and good emulsifying properties. The X-ray diffraction study of the mesophases and of dry lipopeptides showed the existence of three types of mesomorphic structures lamellar, cylindrical hexagonal and body-centred cubic. Two types of polymorphism were also identified one as a function of the length of the peptidic chain and the other as a function of the water content of the mesophases. The emulsifying properties of the lipopeptides in numerous pairs of immiscible liquids such as water/ hydrocarbons and water/base products of the cosmetic industry showed that small amounts of lipopeptides easily give three types of emulsions simple emulsions, miniemulsions and microemulsions. 

This book on polymeric microemulsions is an attempt at a rapprochement of the methods and structures encountered in the two disciplines. The purpose of this book is to investigate polymer-polymer or polymer-surfactant interactions in solution leading to association structures with properties such as solubilization and anisotropy. These properties are useful in a wide variety of industries such as pharmaceutics, cosmetics, textiles, detergents, and paints. 

Ibrahim SA, Hafez E, El-Shanawany SM, et al. Eormulation and evaluation of some topical antimycotics. Part 3. Effect of promoters on the in vitro and in vivo efficacy of clotrimazole ointment. Bull Pharm Sci Assiut XJniv 1991 14(1-2) 82-94. Swafford SK, Bergmann WR, Migliorese KG, et al. Characterization of swollen micelles containing linoleic acid in a microemulsion system. / Soc Cosmet Chem 1991 42 235-247. 

Polyoxyethylene alkyl ethers are nonionic surfactants widely used in topical pharmaceutical formulations and cosmetics, primarily as emulsifying agents for water-in-oil and oil-in-water emulsions and the stabilization of microemulsions and multiple emulsions. 

Sorbitan esters are widely used in cosmetics, food products, and pharmaceutical formulations as lipophilic nonionic surfactants. They are mainly used in pharmaceutical formulations as emulsifying agents in the preparation of creams, emulsions, and ointments for topical application. When used alone, sorbitan esters produce stable water-in-oil emulsions and microemulsions but are frequently used in combination with varying... 

The wide spectrum of self-assembly phenomena can be categorized in various ways. In this entry, we discuss the similarities and the differences between two- and three-dimensional systems. The last section of this entry describes recent and possible future applications of self-assembly processes, mainly related to advanced materials, environmental issues, biotechnology, and nanotechnology. Emulsions, microemulsions, and foams are examples of important and common applications in which self-assembly plays a key role. These have a wide variety of industry applications from cosmetics, foods, detergents, oil recovery, drug formulation/delivery, petroleum refining, and mining. As these are the subjects of other topics in this encyclopedia, they are not covered here. 

Gallot et al. [60] used hpopeptides to produce stable water-in-oil macroemulsions with a droplet diameter greater than 1 pm. In the presence of a cosurfactant, these emulsions could be transformed into miniemulsions containing droplets of 100-400 nm in diameter (cetyl alcohol) or microemulsions with droplets of lO-lOOnm (C4 amine or alcohol). lipopeptide-alkyl(meth)acrylamide copolymers and acrylamidohposarcosine-alkylacryl-amide copolymers were further used as emulsifiers of cosmetic oils [61]. 

Microemulsions are thermodynamically stable isotropic dispersions of oil in water (o/w) or of water in oil (w/o) containing domains of nanometer dimensions stabilized by an interfacial film of surfactant(s). The most typical oil phases are alkanes, the choice of cyclic or aromatic hydrocarbon being dependent on further application. Extensive study of microemulsions has been stimulated by their great potential for practical applications in different fields [1,2] such as pharmaceuticals, cosmetics, enhanced oil recovery and material science (catalysts, semiconductors, etc.). 

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