Solid emulsion gel as a novel construct for topical applications: synthesis, morphology and mechanical properties

Abstract

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 p-nitrophenyl carbonate poly(ethylene glycol) and protein-stabilized 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 protein-stabilized 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.

Role of liquid crystal in the emulsification of a gel emulsion with high internal phase fraction

“…These emulsions exhibit interesting rheology and often good stability [3][4][5]. One reason for the interest in such emulsions is their promising potential in topical applications, particularly for the encapsulation and release of actives [6][7][8][9] and as reaction media [10]. In recent years their use as templates for polymerization, polymer monoliths and foams [2,[11][12][13][14] has stimulated further interest.…”

Transport in droplet-hydrogel composites: response to external stimuli

“…12 decays exponentially at regions beyond the droplets electrical double layers, and we may neglect the contributions to the integral from the portion of V o lying outside the droplets electrical double layers. Thus, the average current density takes the form (17) where V k is the volume occupied by the electrical double layer of kth droplet (see the insets depicted in Fig. 1).…”

“…As a new type of hydrogel-based composites, emulsion-filled gels (droplet-hydrogel composites) are polymer assemblies that integrate dispersed oil droplets within a water-saturated hydrogel phase. This type of hydrogel-based composites have been developed as a new class of materials for drug delivery, food sciences, and responsive materials [15][16][17]. The rheological and lubrication properties of these composites have been observed to depend on the properties of the hydrogel and droplets, the droplet concentration, and the droplet-hydrogel interactions [18,19].…”

Gel Electrophoresis of a Hydrophobic Liquid Droplet with an Equipotential Slip Surface

“…GE is often used for separation and characterization and size distribution of nanoemulsions. , The nanoemulsions are the dispersion of nanometric size (range generally 10–1000 nm) oily droplets and are often used for dermal delivery systems of genistein. , Besides the emulsion-filled composite hydrogel is a new class of material where the oil droplets are embedded in polymeric hydrogel. This new class of polymeric composite finds widespread applications in drug delivery and food sciences. − The electrorheology of charged droplets within the charged hydrogel medium is studied theoretically by Mohammadi . They have further extended their theoretical study on the response of the DC electric field to the uncharged liquid droplet embedded in charged hydrogel .…”