Preparation and characterization of α-tocopherol nanocapsules based on gum Arabic-stabilized nanoemulsions

Cellulose nanocrystals/cellulose nanofibrils-combined astaxanthin nanoemulsion for reinforcement of targeted tumor delivery of gastric cancer cells

Nanoemulsion based nanomaterial (NE) was carried out in the present study to evaluate the efficacy and its antitumor potential of the gastric cancer cells. NE was prepared with astaxanthin/alpha-tocopherol- cellulose nanocrystals/cellulose nanofibrils based nanoemulsions for gastric cancer treatment. The cytotoxic potential was tested against cancer cells and evaluated in terms of its cell proliferation, migration, and cellular uptake by the standard methods. NE was examined for its synergetic effect with photodynamic therapy (PDT) in a xenograft mouse model. The results confirmed the synergetic effect of PDT and NEs in the in vivo animal model. The regulated expression of proteins manifested the reduced toxicity and inhibition of cell proliferation and migration. The antitumor study showed that NE inhibited the growth of human colon cancer in vivo. Immunohistological analysis confirmed the regulation of PI3K/AKT signaling pathway. The present study demonstrates that NEs can enhance anti-cancer effect against human gastric cancer through the immunomodulatory signaling pathway.

Xanthan and gum acacia modified olive oil based nanoemulsion as a controlled delivery vehicle for topical formulations

In this study, olive oil nanoemulsion modified with xanthan gum and gum acacia was explored as a potential controlled topical delivery vehicle. Oil-in-water nanoemulsion formulated with optimized composition of olive oil, tween 80, and water was used as the drug carrier and further modified with gum. Effect of gum on nanoemulsion different physiochemical characteristics, stability, rheology, drug release and encapsulation efficiency were investigated. Results showed that developed nanoemulsion behaved as low viscosity Newtonian fluid and released 100 % drug within 6 h. Modification with xanthan and gum acacia had significantly improved formulation viscosity, drug encapsulation efficiency (>85 %) and controlled drug release up to 40 % with release pattern following Korsmeyer-Peppas model. Additionally, xanthan gum modified formulation exhibited shear thinning rheology by forming an extended network in the continuous phase, whereas gum acacia modified formulation behaved as Newtonian fluid at high shear rate (>200 s-1). Furthermore, xanthan gum modified formulations had improved zeta potential, stability, monodispersity, and hemocompatibility and showed high antibacterial activity against S. aureus than gum acacia modified formulations. These results indicate the higher potential of xanthan gum modified formulation as a topical delivery vehicle. Moreover, skin irritation test demonstrated the safety of developed formulations for topical application.

Preparation and characterization of vitamin D microemulsions using two-component surface-active stabilizer system

Vitamin D, like other functional lipid bioactive compounds, t suffers from less structural stability, poor water solubility and consequently less bioavailability and cellular uptake. Preparation of vitamin D microemulsions is one of the solutions for the above problems. Thus, in the present study, vitamin D microemulsions were prepared using various one/two-component stabilizer systems, namely, Tween 20 and sodium caseinate in various proportions. The effects of stabilizer components proportions on characteristics of gained vitamin D microemulsions were evaluated using a two-component mixture design of experiment. Therefore, various polynomial models were proposed in order to predict the characteristics of produced microemulsions. According to the optimization analysis, the vitamin D microemulsions stabilized by a stabilizer system composed of 70% Tween 20 and 30% sodium caseinate could produce the most desirable microemulsions with minimum mean particle size, polydispersity, and maximum zeta potential, transparency and vitamin D content. The produced vitamin D microemulsions showed acceptable chemical and good physical stabilities, which can be incorporated easily in water-based food and pharmaceutical formulations.

Effects of rotation speed and time, as solvent removal parameters, on the physico-chemical properties of prepared α-tocopherol nanoemulsions using solvent-displacement technique

A bottom-up approach based on solvent-displacement technique was used to prepare α-tocopherol nanoemulsions. Effects of two main evaporation parameters namely, rotation speed (1 × 10-9 × 10 rpm) and rotation time (5-15 min) of utilized vacuum rotary evaporator, on the mean particle size, polydispersity index (PDI) and α-tocopherol degradation of the formed nanodroplets were evaluated using response surface methodology. Obtained results suggested three polynomial regression models for predicting the studied response variables' affected by selected evaporation parameters. Relatively high coefficients of determination for suggested models (> 0.7839) confirmed the suitability of the generated models. Multiple-optimization procedure revealed that the optimum amounts of evaporation speed and time were 30 rpm and 10 min, respectively, which in that, prepared spherical α-tocopherol nanoemulsions had mean particle size, PDI and concentration values of 48.9 nm, 0.232 and 358.7 mg/L, respectively.

Food-Grade Nanoemulsions: Preparation, Stability and Application in Encapsulation of Bioactive Compounds

Nanoemulsions have attracted significant attention in food fields and can increase the functionality of the bioactive compounds contained within them. In this paper, the preparation methods, including low-energy and high-energy methods, were first reviewed. Second, the physical and chemical destabilization mechanisms of nanoemulsions, such as gravitational separation (creaming or sedimentation), flocculation, coalescence, Ostwald ripening, lipid oxidation and so on, were reviewed. Then, the impact of different stabilizers, including emulsifiers, weighting agents, texture modifiers (thickening agents and gelling agents), ripening inhibitors, antioxidants and chelating agents, on the physicochemical stability of nanoemulsions were discussed. Finally, the applications of nanoemulsions for the delivery of functional ingredients, including bioactive lipids, essential oil, flavor compounds, vitamins, phenolic compounds and carotenoids, were summarized. This review can provide some reference for the selection of preparation methods and stabilizers that will improve performance in nanoemulsion-based products and expand their usage.