Pickering Emulsion

Green coffee oil and modified starch were recently found to have an enhanced protection effect against UV radiation. Therefore, this work aimed to develop an innovative sunscreen formulation based on Pickering emulsions concept, i.e., surfactant-free emulsions stabilized by physical UV filters associated natural oils as a key strategy for prevention against UV-induced skin damage. The Pickering emulsions of different compositions were characterized in terms of pH, mechanical, physical and microbiological stability by a thorough pharmaceutical control. In addition, the sun protection factor (SPF) as well as the in vitro and in vivo biological properties of the final formulations, including Episkin®, HRIPT and sunscreen water resistance. Formulation studies demonstrated the addition of physical UV filters was beneficial, leading to the inclusion of ZnO and TiO2 to ensure a high SPF against UVA and UVB, respectively. Although starch particles presented no intrinsic photoprotection prop...

Virgin coconut oil (VCO) has many health benefits; however, drinking of VCO directly is still uncommon. In order to overcome this problem, microencapsulation can be one of the solutions. Unfortunately, emulsion is an unstable system and rapidly separates into two layers. Therefore, in this study, we carried out the explanatory research of microencapsulation process with descriptive analysis. It comprised two emulsion treatments, using homogenization method, and three drying techniques, to determine the effect of Pickering emulsion with microcrystalline cellulose (MCC) and different drying techniques on the characteristics of VCO powder (before drying: creaming index and emulsion droplet size; and after drying: drying yield, color intensity, moisture content, particle morphology, microencapsulation efficiency, peroxide value, rehydration particle size, and dissolving time). The results demonstrated that all emulsion treatments did not depict any emulsion instability up to 21 days of ...

Pickering emulsions are systems composed of two immiscible fluids stabilized by solid organic or inorganic particles. Pickering emulsions are particularly useful in cosmetics, where the surfactants are unwanted, as well as in the pharmaceutical field, where transdermal and/or dermal drug delivery is difficult to achieve and controlled drug release is desired. Here, we studied calcium carbonate particles as stabilizers of Pickering emulsions for topical use. An optimized formulation was obtained using a Quality by Design approach. First, a screening experiment was performed to identify the formulation and process critical variables that affect the quality properties of the Pickering emulsion. The optimization of the production was then studied by establishing the design space. The final formulation was hereinafter investigated regarding the pH, rheological properties, and in vitro cytotoxicity assays. The results showed the formulation had a pH compatible with human skin and a shear ...

In this study, carbon black/polystyrene electrically conductive composites were obtained by suspension polymerization technique. The composite was characterized using transmission electron microscopy, which indicated two outstanding features concerning to the carbon black; first, that the carbon particles were adsorbed onto the surface of the polystyrene particles, similarly as in the Pickering emulsion phenomenon and second, that the primary aggregate structure

Freeze drying and re-dispersibility of oil-in-water (o/w) emulsions is important from the perspective of storage, transportation and usability. A set of stable and re-dispersible o/w emulsions using polyacryloyl hydrazide (PAHz) capped Ag nanoparticles (NP) as the stabilizer is reported in which the NP size (D avg) and PAHz concentration collectively controlled the stability and re-dispersibility of the emulsion system. O/w emulsions prepared using different concentrations of PAHz (0.05-0.25 g mL À1) and sizes of Ag NPs (10-25 nm) were analyzed by DLS, IFT, contact angle, SEM, and rheological studies. The emulsion stabilized by 0.05 g mL À1 of PAHz and Ag NPs (D avg E 20 nm, 5 wt% PAHz-Ag NPs) was unstable against coalescence, exhibited maximum oil leakage during freeze-drying and lacked re-dispersibility. The stability of the Pickering emulsions was inversely proportional to the D avg of the Ag NPs. The presence of Ag NPs possessing D avg E 10 nm and 0.25 g mL À1 of PAHz in the aqueous phase (25 wt% PAHz-Ag NPs) stabilized the Pickering emulsions for up to 30 days without any sign of creaming and the oil powders (oil content E 98%) obtained after freeze drying exhibited adequate re-dispersibility in aqueous media. In addition, the emulsion stabilized by 25 wt% PAHz-Ag NPs showed maximum recovery of the viscosity value after re-dispersion and exhibited similar shear-thinning behavior to that of the original sample. Furthermore, the trends of moduli vs. frequency for the re-dispersed samples were similar to that of the original samples suggesting that the structural arrangements between Ag NPs and oil droplets were least affected by the drying process. Thus, we conclude that o/w emulsions stabilized by PAHz-Ag NPs can be a potential alternative to produce stable oil powders or gels for industrial applications.