Comparative Study of Physicochemical Properties of Nanoemulsions Fabricated with Natural and Synthetic Surfactants

Plant-Based Oil-in-Water Food Emulsions: Exploring the Influence of Different Formulations on Their Physicochemical Properties

The global focus on incorporating natural ingredients into the diet for health improvement encompasses ω-3 polyunsaturated fatty acids (PUFAs) derived from plant sources, such as flaxseed oil. ω-3 PUFAs are susceptible to oxidation, but oil-in-water (O/W) emulsions can serve to protect PUFAs from this phenomenon. This study aimed to create O/W emulsions using flaxseed oil and either soy lecithin or Quillaja saponins, thickened with modified starch, while assessing their physical properties (oil droplet size, ζ-potential, and rheology) and physical stability. Emulsions with different oil concentrations (25% and 30% w/w) and oil-to-surfactant ratio (5:1 and 10:1) were fabricated using high-pressure homogenization (800 bar, five cycles). Moreover, emulsions were thickened with modified starch and their rheological properties were measured. The physical stability of all emulsions was assessed over a 7-day storage period using the TSI (Turbiscan Stability Index). Saponin-stabilized emulsions exhibited smaller droplet diameters (0.11-0.19 µm) compared to lecithin (0.40-1.30 µm), and an increase in surfactant concentration led to a reduction in droplet diameter. Both surfactants generated droplets with a high negative charge (-63 to -72 mV), but lecithin-stabilized emulsions showed greater negative charge, resulting in more intense electrostatic repulsion. Saponin-stabilized emulsions showed higher apparent viscosity (3.9-11.6 mPa·s) when compared to lecithin-stabilized ones (1.19-4.36 mPa·s). The addition of starch significantly increased the apparent viscosity of saponin-stabilized emulsions, rising from 11.6 mPa s to 2117 mPa s. Emulsions stabilized by saponin exhibited higher stability than those stabilized by lecithin. This study confirms that plant-based ingredients, particularly saponins and lecithin, effectively produce stable O/W emulsions with flaxseed oil, offering opportunities for creating natural ingredient-based food emulsions.

Evaluation of curcumin nanoemulsion effect to prevent intestinal damage

Curcumin has gained great prominence for the prevention and treatment of inflammatory bowel disease. However, studies have reported the low bioavailability of orally administered curcumin. This work aimed to evaluate the characteristics, stability and effects of a curcumin-carrying nanoemulsion in preventing intestinal damage induced by indomethacin. Nanoemulsions containing curcumin were prepared by spontaneous emulsification method and it was characterized by dynamic light scattering (DLS), zeta potential and the morphology was evaluated by scanning electron microscopy (SEM). Its stability was tested under different conditions of pH, temperature at 0, 7, 14, 21 and 28 days. In animal experimentation, 36 male mice of the Mus musculus lineage (C57BL/6) were used. The intestinal inflammation was evaluated based on macroscopic, histopathological and metagenomic analysis. It was found a stable nanoemulsion with a size of 409.8 nm, polydispersion index (PDI) of 0.132 and zeta potential of -18.8 mV. However, these lost charge in pH2, showing instability in acidic media (p < 0.05). In animal experiments, the nanoemulsion did not significantly improve intestinal inflammation. However, the group treated with curcumin nanoemulsion showed a higher relative abundance of the genus Lactobacillus (p < 0.05). In conclusion, the curcumin nanoemulsion was relevant in the modulation of the intestinal microbiota.

Nanoemulsion based edible coatings for quality retention of fruits and vegetables-decoding the basics and advancements in last decade

Fruits and vegetables (F&V) are highly perishable and have important contributions to nutritional and economic sustainability. Although the developing nations have shown an immense increase in the production of horticultural commodities, the post-harvest losses are significant and have an adverse impact on the resources, economy, and environment as well. Nanoemulsion-based carriers are recognized for their diversity, natural origin, and immense potential to restrict losses while boosting the functional attributes of produce. The recent findings attest to nanoemulsions potential for extending the shelf life, managing quality, and reducing the losses of the perishables for sustainable livelihood of the farmers. However, further studies are required to evaluate the biological fate, safety, or potential toxicity of the nanoemulsion-based edible coatings. This review precisely focuses on various matrices used in the production of nanoemulsions, fabrication methods, characterization techniques, and the use of natural emulsifiers instead of chemicals. The future research focus stresses on developing low-cost fabrication techniques for nanoemulsion, improvement of the transmission properties i. e gas transmission rate (GTR), water vapor transmission rate (WVTR), and enhancing the performance of monolayer, bilayer, and other composite nanoemulsion base films. This beyond reducing the postharvest losses shall also restrict burden of the food waste management and related environmental issues at the same time.

A Cocktail-Based Formula for the Design of Nanosized Cosmeceuticals as Skincare and Anti-Age Products

Nasco and Bovale grape pomace extracts, alone or in association, were loaded in nanoemulsions tailored for cosmetic application, using Kolliphor®RH40 (kolliphor) as the synthetic surfactant, Olivem®1000 (olivem) as the natural one, and lecithin as the cosurfactant. Pink transparent or milky dispersions, as a function of the used extract and surfactant, were obtained to be used as cosmeceutical serum or milk. The sizes of the nanoemulsion droplets were small (≈77 nm with kolliphor and ≈141 nm with olivem), homogenously dispersed (~0.24 with kolliphor and ~0.16 with olivem), highly negatively charged (≈-43 mV irrespective of the used surfactant) and their stability either on storage or under stressing conditions was affected by the used extract and surfactant. Formulations protected the extracts from the degradation caused by UV exposition, were biocompatible against keratinocytes, protected them against oxidative damages induced using hydrogen peroxide and inhibited the release of nitrite induced in macrophages using the lipopolysaccharide inflammatory stimulus. The overall results underlined the key role played by the composition of the formula to achieve a suitable cosmeceutical for skin care but even for the prevention of premature aging and chronic damages caused by the stressing conditions.

Curcumin: Overview of Extraction Methods, Health Benefits, and Encapsulation and Delivery Using Microemulsions and Nanoemulsions

Curcumin is the principal curcuminoid found in the rhizomes of turmeric. Due to its therapeutic action against cancer, depression, diabetes, some bacteria, and oxidative stress, it has been used widely in medicine since ancient times. Due to its low solubility, the human organism cannot completely absorb it. Advanced extraction technologies, followed by encapsulation in microemulsion and nanoemulsion systems, are currently being used to improve bioavailability. This review discusses the different methods available for curcumin extraction from plant material, methods for the identification of curcumin in the resulting extracts, its beneficial effects on human health, and the encapsulation techniques into small colloidal systems that have been used over the past decade to deliver this compound.

Fabrication, characterization, and interventions of protein, polysaccharide and lipid-based nanoemulsions in food and nutraceutical delivery applications: A review

The fabrication and application of nanoemulsions for incorporating and delivering diverse bioactive compounds, particularly hydrophobic substances, is becoming an increasing focus of research with the potential to improve the nutritional and health status of individuals. Constant advancements in nanotechnological approaches aid in the creation of nanoemulsions using diverse biopolymers such as proteins, peptides, polysaccharides, and lipids to improve the stability, bioactivity, and bioavailability of active hydrophilic and lipophilic compounds. This article provides a comprehensive overview of various techniques used to create and characterize nanoemulsions as well as theories for understanding their stability. The article also highlights the advancement of nanoemulsions in boosting the bioaccessibility of nutraceuticals to help advance their potential use in various food and pharmaceutical formulations.

Fabrication and characterization of nanoemulsions for encapsulation and delivery of vitexin: antioxidant activity, storage stability and in vitro digestibility

BACKGROUND

Nanoemulsions were prepared as an encapsulation and delivery system for vitexin, a poorly water-soluble antioxidant. This study evaluated how the type and concentration of the dispersed oil phase and vitexin loading impacted droplet characteristics and nanoemulsion stability. The influences of storage temperature on antioxidant activity and in vitro gastrointestinal digestion on nanoemulsion stability were also investigated.

RESULTS

Nanoemulsions prepared at different dispersed oil concentrations showed diverse characteristics and stability. Highest stability against droplet aggregation and phase separation with small oil droplets (< 150 nm) was observed for nanoemulsions prepared using 300 g kg^-1 medium-chain triglyceride oil. These nanoemulsions are able to entrap and deliver vitexin with high encapsulation efficiency (88-90%) with no significant effect on emulsion stability. Vitexin-loaded nanoemulsions were stable during storage when refrigerated (4 °C) and at room temperature (25 °C) for up to 45 days with no effect on their antioxidant activity. Significantly delayed lipolysis rate and decreased extent of lipid digestion were observed in vitexin-loaded nanoemulsions.

CONCLUSIONS

Stable vitexin-loaded nanoemulsions were successfully produced by high-pressure homogenization using a mixture of Tween 80 and lecithin as emulsifiers. Vitexin-loaded nanoemulsions stabilized with a mixture of these two emulsifiers were effective in retaining antioxidant activity during storage and protecting vitexin from changes during gastrointestinal digestion. Our results suggested that nanoemulsions were effective vitexin delivery systems for food applications. © 2022 Society of Chemical Industry.

Optimized Green Nanoemulsions to Remove Pharmaceutical Enoxacin from Contaminated Bulk Aqueous Solution

We attempted to develop green nanoemulsions (ENE1-ENE5) using capryol-C90 (C90), lecithin, Tween 80, and N-methyl-2-pyrrolidone (NMP). HSPiP software and experimentally obtained data were used to explore excipients. ENE1-ENE5 nanoemulsions were prepared and evaluated for in vitro characterization parameters. An HSPiP based QSAR (quantitative structure-activity relationship) module established a predictive correlation between the Hansen solubility parameter (HSP) and thermodynamic parameters. A thermodynamic stability study was conducted under stress conditions of temperature (from -21 to 45 °C) and centrifugation. ENE1-ENE5 were investigated for the influence of size, viscosity, composition, and exposure time on emulsification (5-15 min) on %RE (percent removal efficiency). Eventually, the treated water was evaluated for the absence of the drug using electron microscopy and optical emission spectroscopy. HSPiP program predicted excipients and established the relationship between enoxacin (ENO) and excipients in the QSAR module. The stable green nanoemulsions ENE-ENE5 possessed the globular size range of 61-189 nm, polydispersity index (PDI) of 0.1-0.53, viscosity of 87-237 cP, and ζ potential from -22.1 to -30.8 mV. The values of %RE depended upon the composition, globular size, viscosity, and exposure time. ENE5 showed %RE value as 99.5 ± 9.2% at 15 min of exposure time, which may be due to the available maximized adsorption surface. SEM-EDX (scanning electron microscopy-X-ray dispersive energy mode) and inductively coupled plasma-optical emission spectroscopy (ICP-OES) negated the presence of ENO in the treated water. These variables were critical factors for efficient removal of ENO during water treatment process design. Thus, the optimized nanoemulsion can be a promising approach to treat water contaminated with ENO (a potential pharmaceutical antibiotics).

Surface Properties of Graffiti Coatings on Sensitive Surfaces Concerning Their Removal with Formulations Based on the Amino-Acid-Type Surfactants

Water-in-oil (w/o) nanoemulsions stabilized with amino acid surfactants (AAS) are one example of nanotechnology detergents of the "brush on, wipe off"-type for removing graffiti coatings from different sensitive surfaces. The high-pressure homogenization (HPH) process was used to obtain the nanostructured fluids (NSFs), including the non-toxic and eco-friendly components such as AAS, esterified vegetable oils, and ethyl lactate. The most effective NSF detergent was determined by response surface methodology (RSM) optimization. Afterwards, several surface properties, i.e., topography, wettability, surface free energy, and the work of water adhesion to surfaces before and after their coverage with the black graffiti paint, as well as after the removal of the paint layers by the eco-remover, were determined. It was found that the removal of graffiti with the use of the NSF detergent is more dependent on the energetic properties and microporous structure of the paint coatings than on the properties of the substrates on which the layers were deposited. The use of NSFs and knowledge of the surface properties could enable the development of versatile detergents that would remove unwanted contamination from various surfaces easily and in a controlled way.

Size-Controlled Preparation of Docetaxel- and Curcumin-Loaded Nanoemulsions for Potential Pulmonary Delivery

Lung cancer is one of the deadliest pulmonary diseases in the world. Although docetaxel (DTX) has exhibited superior efficacy in lung cancer treatment, it has demonstrated numerous adverse effects and poor bioavailability. The natural product extract, curcumin (CCM), has reportedly reduced toxicity and synergistically improved DTX bioavailability. Nonetheless, the hydrophobic nature of DTX and CCM limits their clinical use. Nanoemulsion pulmonary delivery of DTX and CCM has demonstrated potential as a drug carrier to alleviate these drawbacks. The controlled preparation of inhalable DTX- and CCM-loaded nanoemulsions within the 100 to 200 nm range was explored in this study. A response surface methodology (RSM) based on a central composite design (CCD) was utilized to fabricate the desired size of the nanoemulsion under optimized conditions. Different process parameters were employed to control the size of the nanoemulsions procured through a high-energy emulsification technique. The size of the resultant nanoemulsions decreased with increasing energy input. The actual response according to the targeted sizes for DTX- and CCM-loaded nanoemulsion models exhibited excellent agreement with the predicted value at below 5% residual standard error under optimized conditions. The nanoemulsion of 100 nm particle size demonstrated better membrane permeability than their larger counterparts. Moreover, the formulations documented favorable physicochemical and aerodynamic pulmonary delivery properties and reduced toxicity in human lung fibroblast (MRC-5) cells. Hence, this tunable size of nanoemulsions could be a suitable alternative drug delivery for pulmonary diseases with increased local lung concentration.

Cholecalciferol- and α-tocopherol-loaded walnut oil emulsions stabilized by whey protein isolate and soy lecithin for food applications

BACKGROUND

To overcome the limitations in the use of protein as an emulsifier, soy lecithin, a natural surfactant, was used along with whey protein isolate (WPI) to produce o/w emulsions containing cholecalciferol and α-tocopherol. The physical stability of the emulsions prepared with WPI and varying concentrations of lecithin (0, 1, 2, and 3% w/w) was measured in different heat, pH, and ionic-strength food environmental conditions.

RESULTS

All emulsions were shown to be less than 250 nm in size and less than 0.3 in polydispersity index (PDI). The morphology of the emulsions was spherical, and the droplets of the emulsion containing lecithin were thicker and larger than those of the emulsion without lecithin (WPI_L0). After autoclaving, WPI_L0 increased in size from 197.8 ± 1.7 nm to 528.5 ± 28.4 nm, and the retention of cholecalciferol and α-tocopherol decreased to 40.83 ± 0.63% and 49.68 ± 1.84%, respectively. At pH 5.5, near the isoelectric point of WPI, WPI_L0 increased in size due to aggregation, but emulsions containing lecithin remained stable at a PDI under 0.3. Turbiscan stability index of the emulsion prepared with WPI and 3% lecithin was the lowest, indicating good storage stability. In addition, it was confirmed that the higher the lecithin content, the higher the viscosity, and the higher the amount of free fatty acids released in the in vitro digestion model.

CONCLUSION

This study can provide theoretical evidence for enhancing the physical stability of protein emulsions by co-stabilization with lecithin, promoting their application in various foods. © 2022 Society of Chemical Industry.

Formulation and Characterization of O/W Nanoemulsions of Hemp Seed Oil for Protection from Steatohepatitis: Analysis of Hepatic Free Fatty Acids and Oxidation Markers

Non-alcoholic steatohepatitis (NASH) is a common type of metabolic liver disease which is characterized by fatty changes associated with hepatocyte injury, lobular inflammation, and/or liver fibrosis. Nanoemulsions are kinetically stable colloidal systems characterized by small droplet size. Hemp seed oil is a natural oil derived from Cannabis sativa seeds. The current study was designed to formulate nanoemulsion preparations of hemp seed oil with promising enhanced biological activity against high fat (HF) diet induced NASH in rats. Four nanoemulsion formulas (NEFs) were formulated based on high-pressure homogenization technique and evaluated for droplet size, zeta potential (ZP), polydispersity index (PDI), electrical conductivity, pH, and viscosity, as well as the preparation stability. The best NEF was selected to perform an in vivo rat study; selection was based on the smallest droplet size and highest physical stability. Results showed that NEF#4 showed the best physiochemical characters among the other preparations. Twenty male rats were assigned to four groups as follows: normal, NASH control, NASH + hemp seed oil and NASH + hemp seed oil NEF4. The rats were tested for body weight (BWt) change, insulin resistance (IR) and hepatic pathology. The hemp seed NEF#4 protected against NASH progression in rats and decreased the % of BWt gain compared to the original Hemp seed oil. NEF#4 of Hemp seed oil showed greater protective activity against experimental NASH and IR in rats. Hence, we can consider the nanoemulsion preparations as a useful tool for enhancing the biological action of the hemp seed oil, and further studies are warranted for application of this technique for preparing natural oils aiming at enhancing their activities.

Nanocarriers for Drug Delivery: An Overview with Emphasis on Vitamin D and K Transportation

Mounting evidence shows that supplementation with vitamin D and K or their analogs induces beneficial effects in various diseases, e.g., osteoarticular, cardiovascular, or carcinogenesis. The use of drugs delivery systems via organic and inorganic nanocarriers increases the bioavailability of vitamins and analogs, enhancing their cellular delivery and effects. The nanotechnology-based dietary supplements and drugs produced by the food and pharmaceutical industries overcome the issues associated with vitamin administration, such as stability, absorption or low bioavailability. Consequently, there is a continuous interest in optimizing the carriers' systems in order to make them more efficient and specific for the targeted tissue. In this pioneer review, we try to circumscribe the most relevant aspects related to nanocarriers for drug delivery, compare different types of nanoparticles for vitamin D and K transportation, and critically address their benefits and disadvantages.

Insights from a Box-Behnken Optimization Study of Microemulsions with Salicylic Acid for Acne Therapy

The present study brings to attention a method to develop salicylic acid-based oil in water (O/W) microemulsions using a tensioactive system based on Tween 80, lecithin, and propylene glycol (PG), enriched with a vegetable oat oil phase and hyaluronic acid. The systems were physically characterized and the Quality by design approach was applied to optimize the attributes of microemulsions using Box–Behnken modeling, combined with response surface methodology. For this purpose, a 3³ fractional factorial design was selected. The effect of independent variables namely X1: Tween 80/PG (%), X2: Lecithin (%), X3: Oil phase (%) was analyzed considering their impact upon the internal structure and evaluated parameters chosen as dependent factors: viscosity, mean droplet size, and work of adhesion. A high viscosity, a low droplet size, an adequate wettability—with a reduced mechanical work—and clarity were considered as desirable for the optimal systems. It was found that the optimal microemulsion which complied with the established conditions was based on: Tween 80/PG 40%, lecithin 0.3%, oat oil 2%, salicylic acid 0.5%, hyaluronic acid 1%, and water 56.2%. The response surface methodology was considered an appropriate tool to explain the impact of formulation factors on the physical properties of microemulsions, offering a complex pattern in the assessment of stability and quality attributes for the optimized formulation.