Nanoemulsions have practical application in a multitude of commercial areas, such as the chemical, pharmaceutical and cosmetic industries. Cosmetic industries use rice bran oil in sunscreen formulations, anti ageing products and in treatments for skin diseases. The aim of this study was to create rice bran oil nanoemulsions using low energy emulsification methods and to evaluate their physical stability, irritation potential and moisturising activity on volunteers with normal and diseased skin types.

This study aimed to produce and characterize an oil in water (O/W) nanoemulsion containing Opuntia ficus-indica (L.) Mill hydroglycolic extract, as well as evaluate its preliminary and accelerated thermal stability and moisturizing efficacy. The formulations containing 0.5% of xanthan gum (FX) and 0.5% of xanthan gum and 1% of Opuntia ficus-indica Mill extract (FXE) were white, homogeneous and fluid in aspect. Both formulations were stable during preliminary and accelerated stability tests. FX and FXE presented a pH compatible to skin pH (4.5–6.0); droplet size varying from 92.2 to 233.6 nm; a polydispersion index (PDI) around 0.200 and a zeta potential from −26.71 to −47.01 mV. FXE was able to increase the water content of the stratum corneum for 5 h after application on the forearm. The O/W nanoemulsions containing 1% of Opuntia ficus-indica (L.) Mill extract presented suitable stability for at least for 60 days. Besides, this formulation was able to increase the water content of stratum corneum, showing its moisturizing efficacy.

Oil-in-water nanoemulsions are stable systems with droplet sizes in the 20–200 nm range. The physicochemical properties of these systems may be influenced by the addition of additives. Thus, the influence of ethoxylated (EL) and acetylated lanolin (AL) addition on the droplet size, pH values, electrical conductivity and stability of nanoemulsions was investigated. Then, effect of nano-emulsions additives with EL (NE-EL) or AL (NE-AL) in hydration, oiliness and pH of the skin were evaluated. Nanoemulsion safety was evaluated through the observation of no undesirable effects after skin formulation application. Both additives caused changes in droplet size and electrical conductivity, but not in pH values. Nanoemulsions containing up to 6.0% ethoxylated lanolin and 2.0% acetylated lanolin remained stable after centrifugation tests. Higher concentrations of the additives made the nanoemulsions unstable. Stability tests showed that ethoxylated lanolin produced more stable nanoemulsions then acetylated lanolin and that the major instability phenomenon occurring in these systems is coalescence at elevated temperatures. Nanoemulsion-based lanolin derivatives increased skin hydration and oiliness and did not change cutaneous pH values. These formulations are non-toxic since they did not cause any irritation on the skin surface after nanoemulsion application, showing potential as carriers for pharmaceuticals and cosmetic applications.

Oil/Water nanoemulsions were obtained, employing PEG castor oil derivatives/fatty esters surfactant, babassu oil, and purified water from a study based on phase diagrams. The nanoemulsions had been prepared by a low energy process inversion phase emulsion. Different parameters, such as order of addition of the components, temperature, stirring speed, and time, were studied to prepare O/W nanoemulsions. The influence of vegetable extract addition on size distribution of nanoemulsions was also analyzed. Evaluation of the nanoemulsions was studied in vitro by HET-CAM and RDB methods. Stable transparent bluish O/W babassu oil nanoemulsion were obtained with surfactant pair fatty ester/PEG-54 castor oil, in an HLB_required value = 10.0 and with a particle droplet size of 46 ± 13 nm. Vegetable extract addition had not influenced nanoemulsion’s stability. The results obtained for in vitro and in vivo nanoemulsion evaluation, based on the hydration and oiliness, and pH of the skin, shows O/W nanoemulsions as potential vehicle for topical application.

The Brazilian biodiversity offers a multiplicity of raw materials with great potential in cosmetics industry applications. Some vegetable oils and fatty esters increase skin hydration by occlusivity, keeping the skin hydrated and with a shiny appearance. Sunflower (Helianthus annus L.) oil is widely employed in cosmetic emulsions in the form of soaps, creams, moisturizers and skin cleansers due to the presence of polyphenols and its high vitamin E content. Liquid crystals are systems with many applications in both pharmaceutical and cosmetic formulations and are easily detected by microscopy under polarized light due to their birefringence properties. The aim of this research was to develop emulsions from natural sunflower oil for topical uses. Sunflower oil (75.0% w/w) was combined with liquid vaseline (25.0% w/w) employing a natural self-emulsifying base (SEB) derivative. The high temperature of the emulsification process did not influence the antioxidant properties of sunflower oil. Fatty esters were added to cosmetic formulations and extended stability tests were performed to characterize the emulsions. Fatty esters like cetyl palmitate and cetyl ester increase the formation of anisotropic structures. O/W emulsions showed acidic pH values and pseudoplastic behavior. The presence of a lamellar phase was observed after a period of 90 days under different storage conditions.