Moisturizing emulsion systems based on the novel long-chain alkyl polyglucoside emulsifier (original) (raw)
Related papers
Journal of Colloid and Interface Science, 2011
To be considered as a suitable vehicle for drugs/cosmetic actives, an emulsion system should have a number of desirable properties mainly dependent on surfactant used for its stabilization. In the current study, C 12-14 alkyl polyglucoside (APG)-mixed emulsifier of natural origin has been investigated in a series of binary (emulsifier concentration 10-25% (w/w)) and ternary systems with fixed emulsifier content (15% (w/w)) with or without glycerol. To elucidate the systems' colloidal structure the following physicochemical techniques were employed: polarization and transmission electron microscopy, X-ray diffraction (WAXD and SAXD), thermal analysis (DSC and TGA), complex rheological, pH, and conductivity measurements. Additionally, the emulsion vehicles' skin hydration potential was tested in vivo, on human skin under occlusion. In a series of binary systems with fixed emulsifier/water ratios ranging from 10/90 to 25/75 the predominance of a lamellar mesophase was found, changing its character from a liquid crystalline to a gel crystalline type. The same was observed in gel emulsions containing equal amounts of emulsifier and oil (15% (w/w)), but varying in glycerol content (0-25%). Different emulsion samples exhibited different water distribution modes in the structure, reflecting their rheological behavior and also their skin hydration capacity.
2004
Oil-in-water (o/w) emulsions forcosmetic use. such as lotions and creams, are complex multiple-phase sys tems, which may contam a number of interacting surfactants. fatty amphiphiles, polymers and other excipients. This study investigates the iniluence of two synthetic cationic polymers, Polyquaternium-7 and Polyquaternium-11, and the natural anionic polymer. gum of acacia. on the rheology and micro structure of creams prepared with a non-ionic mixed emulsifier (cetyl stearyl alcohol-12E0/cetyl alcobol) using rheology (continuous shear, and viscoelastic creep and oscillation), microscopy and differential scanning calorimetry (DSC). A control cream con taining no polymer was also investigated. The semi solid control cream was structured by a swollen lameliar gel network phase formed from the interac tion of cetyl alcohol and the POE surfactant, in cxccss ofthat required to stabilize oil droplets. with continu ous phase water. Endothermic transitions between 25 and 100 C were identified as components of this phase. Incorporation of cationic polymer into the for mulation caused significant Ioss of structure to pro duce a mobile semisolid containing larger ou droplets. The microscopical and thermal data implied that the cationic polymer caused the swollen lamel lar gel network phase to transform into non-swollen crystals of cetyl alcohol. In contrast, incorporation ofgum of acacia produced a thicker creatn than the control, with smallcrdroplet sizes and little evidence of the gel network. Microscopical and thermal data implied that although there were also interactions between gum of acacia and both the surfactant and the swollen gel network phase. the semisolid proper ties were probably because of the ability of the gum ofacacia to stabulize and thicken the emulsion in the absence of the swollen lamellar network.
Pharmaceutics, 2019
Topical formulations are an important pillar in the therapy of skin diseases. Nevertheless, after application the formulation will be exposed to environmental effects. Contact with other surfaces will reduce the available amount of formulation and drug substance. The resulting consequences for therapy range from reduced effects to therapeutic failure. The removed active ingredient also contaminates patients’ environment. The aim of this work was to develop preparations that remain at the application site. These will enhance safety and efficiency and thus improve of skin disease therapies. Therefore, we developed polymer-stabilised emulsions that show thermogelling properties. Emulsions with different methyl cellulose concentrations and macrogols of different molecular weights were investigated. The dispersed phase consisted of nonivamide as the active pharmaceutical ingredient, dissolved in medium-chain triglycerides. Rheological properties, droplet size, substantivity and ex vivo p...
Journal of Materials Science: Materials in Medicine, 2009
A series of the solid emulsion gels with the oil volume fraction in the range of 0-50% were synthesized through a polycondensation reaction between activated pnitrophenyl carbonate poly(ethylene glycol) and proteinstabilized oil-in-water emulsions. The resultant structures were investigated in terms of swelling behavior, composition, morphology, mechanical and skin hydration properties. Solid emulsions gels share the properties of both hydrogel and emulsion. Similar to the classical hydrogel, the SEG swells in water up to equilibrium swelling degree, which decreases as the oil volume fraction increases, and comprises immobilized drops of proteinstabilized oil. The impregnation of the oil phase is found to reduce tensile stiffness of the material, but improves material's extensibility. The mechanical properties of the constructs (Young moduli in the range of 9-15 kPa and the elongation at break of 120-220%) are interpreted according to the ''rule of elasticity mixture'' that considers the elasticity of the composite material to be a sum of the contributions from individual components, i.e. hydrogel and dispersed oil drops. An idealized model that takes into account the history of the material preparation has been proposed to explain the improved extensibility of the constructs. The results of the mechanical tests, equilibrium swelling, and the skin hydration effect of the solid emulsion gels in vivo are discussed from the perspective of the biomedical applications of the solid emulsion gels, in particular, for the transdermal delivery of hydrophilic and lipophilic drugs.
Journal of Pharmaceutical Sciences, 2009
There is a growing need for in-depth research into new skin-and environment-friendly surfactants, such as alkylpolyglucosides. The aim of this study was to assess whether, to which extent and by what mechanism the two commonly used hydrophilic excipients, propylene glycol (PG) and glycerol (GL), affect the colloidal structure of emulsions formed by a natural mixed emulsifier, cetearyl glucoside and cetearyl alcohol. Furthermore, the study was concerned with the effect of these changes on in vitro permeation profiles of two model drugs (diclofenac sodium and caffeine) and in vivo skin performance of the test samples. The results have shown that the emulsion vehicles consisted of a complex colloidal structure of lamellar liquid crystalline and lamellar gel crystalline type. PG addition produced a stronger hydrophilic lamellar gel phase than GL, which was independent on the model drug used. PG-containing vehicles have revealed a considerable amount of interlamellar PG/water mixture, with incorporated drug. In vitro permeation data obtained using artificial skin constructs (ASC) confirmed the relationship between rheological profiles of vehicles and the extent of skin delivery. Higher permeation profiles of both drugs from PG-containing formulations coincided with a higher increase in transepidermal water loss observed in in vivo study on human volunteers, which confirms the penetration/permeation enhancer effect of PG. It also indicates the existence of the vehicle/ASC interactions analogous to those between the vehicle and the skin, thus affirming the use of ASC as a reliable tool for permeation studies. Contrary to the effect of PG, the results obtained with GL suggest that it may have a permeation-retarding rather than a permeation-enhancing effect in topical vehicles of this type.
Pharmaceutical Development and Technology, 2014
The aim of this work is to develop, optimize and characterize cold process emulsions that are stable at acidic pH. The main surfactant was selected according to the hydrophilic lipophilic balance (HLB) concept and surface tension, whereas polymers were selected by viscoelastic measurements and analytical centrifugation. It was showed that the inclusion of methyl vinyl ether/maleic anhydride copolymer crosslinked with decadiene (PVM/MA) increased the storage modulus (G 0 ) of the gels (23.9-42.1 Pa) two-fold and the droplet migration decreased from 3.66% to 0.95%/h. Cetrimide was selected as a preservative based on its microbiological results and additional contribution to the stability of the emulsions. Four emulsions were developed that differed by the co-emulsifier used (PEG-20 glyceril laurate and polyglyceryl-4-isostearate) and the glycol (2-methyl-2,4-pentanediol and ethoxydiglycol). Viscoelastic measurements and droplet size/microscopic analysis showed that the structure of PEG-20 glyceril laurate emulsion (' ¼ 76.0 Pa.s at 0.01 Hz and 32.9 AE 3.7 mm, respectively) was stronger compared to polyglyceryl-4-isostearate (' ¼ 37.4 Pa.s at 0.01 Hz and 37.8 AE 15.7 mm, respectively). Differential scanning calorimetry (DSC) results were in accordance with the latter and showed that PEG-20 glyceril laurate with 2-methyl-2,4-pentanediol corresponded to the strongest structure (j224.4j W C g À1 ). This cold process allowed a total production savings of more than 17% when compared to the traditional hot process.
Multiple-phase oil-in-water emulsions
2000
Cosmetic oil-in-water emulsions such as lotions and creams are complex multiple-phase systems. In their preparation, combinations of fatty amphiphiles (glyceryl monoesters or fatty alcohols) and ionic or nonionic surfactants are widely used. The mixed emulsifier combinations interact in the aqueous continuous phases to form lameliar or crystalline structures. These both stabilise and sometimes control the consistencies of emulsions between wide limits. There is, however, confusion as to the type of lameliar phase that forms in a specific emulsion. The majority of the literature fails to distinguish between the lamellar liquid crystalline state and the equally important lamellar gel state. Although liquid crystalline phases form in many emulsions at the high temperatures of manufacture, these often convert to gel phases when the emulsion cools so that the properties of this phase dominate the emulsion.
Journal of Dispersion Science and Technology, 2012
The aim of this research was to characterize emulsion systems (ES) containing nonionic ethoxylated surfactants by using rheological, microscopic, and thermogravimetric assays. Three formulations were developed: ES-1: 8.0% (w/w) oleth-20; ES-2: 4.0% (w/w) oleth-20 / 4.0% (w/w) steareth-21; and ES-3: 8.0% (w/w) steareth-21. The systems showed typical non-Newtonian pseudo-plastic behavior. The presence of a lamellar gel phase was observed for all systems, with ES-2 being more pronounced. Through thermogravimetry, the profiles of the three systems were found to be similar, consisting of two main events, the first one being characterized by loss of water and, beyond 110 C, by loss of the oil phase.
Rheological investigation of pectin-based emulsion gels for pharmaceutical and cosmetic uses
Rheologica Acta, 2014
Emulsion gels are structured emulsions suitable for different uses for their specific behaviour, which is strongly dependent on the characteristics of the gelled dispersing phase. Therefore, it is important to adopt the specific gelling agent to tune the final emulsion rheological behaviour properly. Pectin is extremely interesting among potential hydrophilic gelling agents owing to its specific characteristics. In the present work, four different low-methoxyl pectins were adopted to prepare gels to be used as the dispersing phase in cosmetic or pharmaceutical emulsion gels. The rheological characterisation of pectin gels, prepared at room temperature to avoid the damage to potential thermolabile components, was carried out with small amplitude oscillations. The obtained gels were used, together with a common non-ionic surfactant (Tween 60), to prepare olive oil emulsion gels suitable to design new cosmetic products. A simple empirical model, proposed to relate the emulsion complex modulus to the oil fraction and properties of the dispersing phase, has shown itself to be a potentially useful tool to design formulations with desired properties.