Low-energy Emulsification Method Research Articles

Caffeine-Containing Emulsion: Influence of the HLB and Mixing Proportions, the Oil's Chemical Composition, and the Existence of Caffeine on Emulsion Properties.

This study employs a low-energy emulsification method to prepare caffeine-containing emulsions, denoted as Caf-EM. Three different oils, including coconut, sesame, and grape seed oils, are utilized along with the surfactants Span 80 and Tween 80. We investigate the influence of various factors, including (i) the hydrophilic-lipophilic balance (HLB) and surfactant ratio, (ii) the chemical composition of the oils, and (iii) the presence of caffeine, on the stability and size of emulsions. The results indicate that the HLB value and surfactant ratio are the most crucial factors affecting the emulsions' stability. The most stable Caf-EM formulation is achieved by combining mixed surfactants of Span 80 and Tween 80 with an optimal HLB value of 6.4 at a concentration of 15% (S15 to 6.4) across all oil types. This specific ratio also leads to significantly smaller emulsion droplet sizes than other ratios and is the only ratio that produces stable emulsions even without caffeine (denoted as EM). Notably, formulation S15-6.4 additionally causes a phase inversion from oil-in-water (O/W) to water-in-oil (W/O). Furthermore, the presence of caffeine in the water phase contributes to the formation of smaller and more stable emulsions. The particle size of Caf-EM is approximately 1.5 times smaller than that of EM. Regarding the oil's chemical composition, while there is a discernible trend in emulsion droplet size (coconut oil > grape seed oil > sesame oil), the differences within this sequence are insignificant, suggesting that the oil's chemical composition does not have a pronounced effect.

Use of Double Gelled Microspheres to Improve Release Control of Cinnamon-Loaded Nanoemulsions.

The use of nanoemulsions as encapsulation systems for active ingredients, such as cinnamon oil, has been studied. A surfactant based on polyoxyethylene glycerol esters from coconut/palm kernel oil has been used. The nanoemulsions were obtained by the two most commonly low-energy emulsification methods, the composition inversion phase (PIC) and the temperature inversion phase (PIT) methods. Nanoemulsions were successfully obtained by both methods, with very small droplet sizes (5-14 nm) in both cases, but a greater stability was observed when the PIT method was used. Nanoemulsions were encapsulated by external gelation using two different polysaccharides, alginate or chitosan, dissolved in the continuous phase of the nanoemulsion. Then, the nanoemulsion was dropped into a bath with a gelling agent. To improve the release control of cinnamon oil and avoid the burst effect, beads prepared with one of the polysaccharides were coated with the second polysaccharide and then gelled again. Double gelled beads were successfully obtained, the core with chitosan and the outer layer (shell) with alginate. SEM images showed the morphology of the single beads presenting high porosity. When the beads were coated, the porosity decreased because the second polysaccharide molecules covered the pre-existing pores. The smoother surface was obtained when this second layer was, in turn, gelled. The release patterns at pH = 2 and pH = 7 were studied. It was observed that the double gelled bead provided a more gradual release, but maintained approximately the same amount of final released oil. The release patterns were fitted to the Korsmeyer-Peppas model. The fitting parameters reflected the effect of the different coating layers, correlating with different diffusion mechanisms according to the bead core and shell materials.

Simultaneous Intranasal Codelivery of Donepezil and Memantine in a Nanocolloidal Carrier: Optimization, Pharmacokinetics, and Pharmacodynamics Studies.

This work focuses on developing nanoemulsions using a low-energy emulsification method for the codelivery of donepezil and memantine in one dosage form intended to be administered via the intranasal route for enhanced brain delivery. The nanoemulsion formulation was prepared using a low emulsification technique and characterized using various microscopy and nasal ciliotoxicity studies. The safe nanoemulsion was intended for preclinical pharmacokinetics with brain distribution and pharmacodynamics in a scopolamine-induced murine model. The formulated nanoemulsion was 16 nm in size, with a zeta potential of -7.22 mV, and exhibited a spherical shape. The brain concentration of IN-administered NE for DPZ and MEM was ∼678 and 249 ng/mL after 15 min. This concentration is more than 2 times higher in amount when compared with NE administered via PO, free drug solution administered via IN and PO route both. However, the plasma concentration of IN-administered NE for DPZ and MEM was ∼3 and 28 ng/mL after 15 min. In pharmacodynamic studies, the efficacy of NE administered via the IN route was higher when compared with other groups in neurobehavioral, biochemical estimation, and gene expression studies. The results suggest that the IN route can be explored in the future for the delivery of actives via nanocolloidal carriers in the brain for neurological disorders and can serve as promising alternatives for conventional dosage forms and routes.

Improvement of hydrolysis efficiency and interfacial properties of zein using nanoemulsions prepared by a low energy emulsification method

Alcalase hydrolysis can improve the interfacial properties and functional features of proteins. It usually reacts in water. However, zein is difficult to dissolve in water due to its amino acid composition, which greatly limits its application in food industry. To achieve heterogeneous hydrolysis of zein, a new and stable reaction system which called bicontinuous microemulsion was constructed. It consisted of Tween-80, absolute ethanol, n-octanol and distilled water. The average particle size of the nanoemulsion system was 18.23 nm. In this dispersion system, alcalase hydrolysis expanded the protein structure, exposed hydrophobic groups and significantly improved the emulsifying activity, foaming capacity and other interface properties. The scavenging activity of DPPH free radicals and ABTS free radicals were greatly promoted, reached 59.66% and 82.91% respectively. This study provides a new idea for enzymatic hydrolysis reaction medium of zein and is conducive to the application of zein in future.

A promising self-nanoemulsifying adjuvant with plant-derived saponin D boosts immune response and exerts an anti-tumor effect.

The low immunogenicity of tumor antigens and unacceptable toxicity of adjuvants has hindered the application and development of tumor vaccines. Hence, we designed a novel anti-tumor vaccine composed of a plant-derived immunostimulant molecular nanoadjuvant (a self-nanoemulsifying system, SND) and the antigen OVA, to reinvigorate the immune response and inhibit tumor progression. In this study, this novel nanoadjuvant with Saponin D (SND) was designed and prepared by low-energy emulsification methods. Several important characteristics of the SND, including morphology, size, polymer dispersity index (PDI), zeta potential, and stability, were estimated, and the cytotoxicity of the SND was evaluated by MTT assay. Additionally, the immune response in terms of antibody titer levels and cellular immunity were evaluated in vivo after immunization with the vaccine, and the preventative and therapeutic effects of this novel vaccine against tumors were estimated. Finally, the antigen release profile was determined by IVIS imaging and by in vivo assay. This SND nanoadjuvant had good characteristics including the average particle size of 26.35 ± 0.225 nm, narrow distribution of 0.221 ± 1.76, and stability zeta potential of -12.9 ± 0.83 mV. And also, it had good stability (size, PDI, zeta potential, antigen stability) and low toxicity in vitro and in vivo, and delayed antigen release in vivo. The humoral immune response (IgG, IgG1, IgG2a, and IgG2b) and cellular immune level (cytokines of splenocytes including IFN-γ, IL-4, IL-1β andIL-17A) were both improved greatly after injected immunization at 0, 14, 28 days with the novel nanoadjuvant and antigen OVA. Importantly, this novel nanoadjuvant combined with OVA might lead to the induction of the prevent and treatment efficacy in the E.G7-OVA tumor-bearing mice. These results suggested that this novel nanoadjuvant encapsulated natural plant immunostimulant molecular OPD could be a good candidate of tumor vaccine adjuvant for reinvigorating the immune response and powerfully inhibiting tumor growth effect.

Study of nanoemulsions using carvacrol/MCT-(Oleic acid-potassium oleate)/ Tween 80 ®- water system by low energy method

Carvacrol is studied in different fields due to its microbial and antioxidant properties. Its use is limited because of the water insolubility and its strong taste. To overcome these problems, carvacrol has been successfully loaded into nanoemulsions. The low-energy emulsification method Phase Inversion Composition (PIC) is used to prepare oil-in-water nanoemulsions in the carvacrol/medium chain triglycerides (MCT)-(oleic acid-potassium oleate/Tween 80 ®)-water system. Oleic acid acts as a co-surfactant when it is neutralized with KOH along the emulsification path changing the spontaneous curvature of the interface when increasing the HLB number from 1 for the oleic acid to 20 for the potassium oleate and, therefore, changing the HLB number of the surfactant mixture. The phases diagrams are studied in order to understand the behaviour of the system and to establish the composition range where nanoemulsions can be obtained. Nanoemulsions are formed when the emulsification path crosses a region of direct or planar structure without excess of oil. Experimental design is performed in order to study the influence of composition variables as carvacrol/MCT ratio and (oleic-oleate)/Tween 80 ® ratio (OL-OT/T80 ratio) on the diameter of the nanoemulsions and their stability. It has been observed the importance of the HLB number of the surfactants mixture in order to obtain small-sized stable nanoemulsions. Surface response graphic shows that (OL-OT)/T80 ratio is a significant parameter in the mean diameter of the nanoemulsions. A minimum diameter is obtained for a (OL-OT)/T80 ratio 45/55 due to the fact that ratio is near the preferred HLB of the oil mixture and the emulsification path contains a wide liquid crystal monophasic region with all the oil incorporated in the structure.Diameters of 19 nm for carvacrol/MCT ratio of 30/70 or diameters of 30 nm for ratios of 45/55 with high stability values presented a good potential to be incorporated into edible films in the future.Regarding nanoemulsions stability an optimum value is also observed for a carvacrol/MCT ratio.The addition of another carrier oil as olive oil instead of MCT showed an improvement of the nanoemulsions stability against Ostwald ripening, probably due to the smaller solubility of olive oil. The use of olive oil does not significantly change the diameter of the nanoemulsion.

Encapsulation of Carvacrol-Loaded Nanoemulsion Obtained Using Phase Inversion Composition Method in Alginate Beads and Polysaccharide-Coated Alginate Beads.

Nanoemulsions have been widely studied as lipophilic compound loading systems. A low-energy emulsification method, phase inversion composition (PIC), was used to prepare oil-in-water nanoemulsions in a carvacrol-coconut oil/Tween 80®-(linoleic acid-potassium linoleate)/water system. The phase behaviour of several emulsification paths was studied and related to the composition range in which small-sized stable nanoemulsions could be obtained. An experimental design was carried out to determine the best formulation in terms of size and stability. Nanoemulsions with a very small mean droplet diameter (16-20 nm) were obtained and successfully encapsulated to add carvacrol to foods as a natural antimicrobial and antioxidant agent. They were encapsulated into alginate beads by external gelation. In order to improve the carvacrol kinetics release, the beads were coated with two different biopolymers: chitosan and pullulan. All formulations were analysed with scanning electron microscopy to investigate the surface morphology. The release patterns at different pHs were evaluated. Different kinetics release models were fitted in order to study the release mechanisms affecting each formulation. Chitosan-coated beads avoided the initial release burst effect, improving the beads' structure and producing a Fickian release. At basic pH, the chitosan-coated beads collapsed and the pullulan-coated beads moderately improved the release pattern of the alginate beads. For acid and neutral pHs, the chitosan-coated beads presented more sustained release patterns.

Formulasi dan Karakterisasi Nanoemulsi Ekstrak Etanol Buah Wualae (Etlingera Elatior (Jack) R.M. Smith)

Wualae (Etlingera elatior (Jack) R.M. Smith) has a high flavonoid content, so it has the potential as an antioxidant and can be used in drug delivery systems, namely nanoemulsions. Nanoemulsions can improve absorption, help dissolve lipophilic drugs and increase bioavailability. This study aims to determine the formulation and characterization of wualae nanoemulsion. The research method used is a low-energy emulsification method. The nanoemulsion is formulated into four formulas with a concentration ratio of tween 80 and PEG 400, namely 50%: 30% (F1), 50%: 10% (F2), 10%: 30% (F3), and 10%: 10% (F4). The characterizations included organoleptic tests, nanoemulsion type tests, viscosity tests, transmittance tests, particle size tests, polydispersity index tests, potential zeta and physical tests, and centrifugation and cycling tests. The results obtained sequentially are F1 has a characteristic odour of clear yellow, type of oil-in-water nanoemulsion, 150 cPa.s, 99%, 14.56 ± 0.666 nm, 0.061 ± 0.017, 1.453 ± 1.23 mV and is stable in the test. F2 has a characteristic odour of clear yellow colour, oil-in-water nanoemulsion type, 900 cPa.s, 97.2%, 13.8 ± 0.781 nm, 0.126 ± 0.066, -5.503 ± 0.57 mV and is stable in difficult tests. F3 has a dirty white type of nanoemulsion oil in 9.5 cPa and is unstable in typical tests. F4 has a characteristic odour of cloudy white colour, oil-in-water nanoemulsion type, 6 cPa.s and is inconsistent in stability testing. Based on the data above, the best wualae fruit extract nanoemulsion formulation is formula 1.

A study on coating of Hydroxypropyl methylcellulose incorporated with a nano-emulsion of Piper betel leaf essential oil to enhance shelf-life and improve postharvest quality of Tomato (Solanum lycopersicum L.)

Edible coating films derived from essential oils effectively preserve farm produce, especially fruits and vegetables, and the technology is widely prevalent in improving their shelf life. The present study aimed to reduce the post-harvest loss and extend the shelf life of tomatoes using edible coatings based on Hydroxypropyl methylcellulose (HPMC) containing Piper betel leaf essential oil nano-emulsion as an antibacterial and bioactive compound. It also aimed for optimal extraction of essential oils (EO) from Piper betel leaves which contain various medicinal, antimicrobial, and antioxidant compounds such as chavibetol, eugenol, and other compounds. The essential oils were extracted, and nano-emulsion was prepared by a low-energy emulsification method and incorporated into edible HPMC composite to determine whether the edible coatings of the nano-emulsion of Piper betel leaf could delay the changes that lead to deterioration of the fruit. Results showed that the coatings delayed 5 % changes in color, 8% weight loss, titratable acidity, ascorbic acid content, soluble solids concentration, lycopene, and decay percentage, compared to uncoated control fruits. It was inferred that tomatoes that were coated with 15% nano-emulsion containing dipping solution showed a significant increase in the shelf life of tomatoes up to 8 days. Therefore, it is suggested to use HPMC containing the Piper betel oil nano-emulsion as an edible coating, extending the shelf-life of tomato fruits post-harvest.

Ferulic acid-loaded polymeric nanoparticles prepared from nano-emulsion templates facilitate internalisation across the blood-brain barrier in model membranes.

A hydroxycinnamic acid derivative, namely ferulic acid (FA) has been successfully encapsulated in polymeric nanoparticles (NPs) based on poly(lactic-co-glycolic acid) (PLGA). FA-loaded polymeric NPs were prepared from O/W nano-emulsion templates using the phase inversion composition (PIC) low-energy emulsification method. The obtained PLGA NPs exhibited high colloidal stability, good drug-loading capacity, and particle hydrodynamic diameters in the range of 74 to 117 nm, depending on the FA concentration used. In vitro drug release studies confirmed a diffusion-controlled mechanism through which the amount of released FA reached a plateau at 60% after 6 hours-incubation. Five kinetic models were used to fit the FA release data as a function of time. The Weibull distribution and Korsmeyer-Peppas equation models provided the best fit to our experimental data and suggested quasi-Fickian diffusion behaviour. Moderate dose-response antioxidant and radical scavenging activities of FA-loaded PLGA NPs were demonstrated using the DPPH˙ assay achieving inhibition activities close to 60 and 40%, respectively. Cell culture studies confirmed that FA-loaded NPs were not toxic according to the MTT colorimetric assay, were able to internalise efficiently SH-SY5Y neuronal cells and supressed the intracellular ROS-level induced by H2O2 leading to 52% and 24.7% of cellular viability at 0.082 and 0.041 mg mL-1, respectively. The permeability of the NPs through the blood brain barrier was tested with an in vitro organ-on-a-chip model to evaluate the ability of the FA-loaded PLGA and non-loaded PLGA NPs to penetrate to the brain. NPs were able to penetrate the barrier, but permeability decreased when FA was loaded. These results are promising for the use of loaded PLGA NPs for the management of neurological diseases.

In Vitro Cellular Activity Evaluation of the Nanoemulsion Vaccine Adjuvant Ophiopogonin D.

As a principal ingredient of vaccines, adjuvants can directly induce or enhance the powerful, widespread, innate, and adaptive immune responses associated with antigens. Ophiopogonin D (OP-D), a purified component extracted from the plant Ophiopogon japonicus, has been found to be useful as a vaccine adjuvant. The problems of the low solubility and toxicity of OP-D can be effectively overcome by using a low-energy emulsification method to prepare nanoemulsion ophiopogonin D (NOD). In this article, a series of in vitro protocols for cellular activity evaluation are examined. The cytotoxic effects of L929 were determined using a cell counting kit-8 assay. Then, the secreted cytokine levels and corresponding immune cell numbers after the stimulation and culture of splenocytes from immunized mice were detected by ELISA and ELISpot methods. In addition, the antigen uptake ability in bone marrow-derived dendritic cells (BMDCs), which were isolated from C57BL/6 mice and matured after incubation with GM-CSF plus IL-4, was observed by laser scanning confocal microscopy (CLSM). Importantly, macrophage activation was confirmed by measuring the levels of IL-1β, IL-6, and tumor necrosis factor alpha (TNF-α) cytokines by ELISA kits after coculturing peritoneal macrophages (PMs) from blank mice with the adjuvant for 24 h. It is hoped that this protocol will provide other researchers with direct and effective experimental approaches to evaluate the cellular response efficacies of novel vaccine adjuvants.

Self crosslinked admicelle-Fe3O4 Janus nanoparticle with high detachment energy to creat low-energy emulsified and ultra-stable Pickering emulsion

By skillfully manipulating self-assembly and self-crosslinking activities of sodium conjugated linoleate in a wax-emulsion approach, we design a route to synthesize Janus (self-crosslinked admicelle)-decorated nano-Fe3O4 (SCA-Fe3O4 nanoparticle). The SCA-Fe3O4 nanoparticle exhibits ultra-high stability against environmental stresses of temperature (25–90 °C), salinity (0.1–1.8 M) and pH (1.8–11.7) relying on its high detachment energy at the oil/water interface to create ultra-stable Pickering emulsions. On the other hand, it is possible to demulsify the ultra-stable emulsions by simultaneously providing an external magnetic field and acidic pH under gently stirring to switch on–off the emulsions. Furthermore, the SCA-Fe3O4 nanoparticle reduces the requirement for energy density of emulsification, and achieves a new energy-saving effect in Pickering emulsion preparation comparable to low-energy emulsification methods in nanoemulsion preparation. Therefore, this strategy has good prospects to create Janus structures of various inorganic nanoparticles by a facile synthesis on the surface of frozen wax spheres, and these Janus particles have potential applications in Pickering emulsifiers, interfacial catalysts, biomedicines, and other multifunctional materials due to their asymmetric structure, unique interfacial characteristics and simplified emulsification operation.

Preparation, Characteristics, Toxicity, and Efficacy Evaluation of the Nasal Self-assembled Nanoemulsion Tumor Vaccine In Vitro and In Vivo.

Epitope peptides have attracted widespread attention in the field of tumor vaccines because of their safety, high specificity, and convenient production; in particular, some MHC I-restricted epitopes can induce effective cytotoxic T lymphocyte activity to clear tumor cells. Additionally, nasal administration is an effective and safe delivery technique for tumor vaccines due to its convenience and improved patient compliance. However, epitope peptides are unsuitable for nasal delivery because of their poor immunogenicity and lack of delivery efficiency. Nanoemulsions (NEs) are thermodynamically stable systems that can be loaded with antigens and delivered directly to the nasal mucosal surface. Ile-Lys-Val-Ala-Val (IKVAV) is the core pentapeptide of laminin, an integrin-binding peptide expressed by human respiratory epithelial cells. In this study, an intranasal self-assembled epitope peptide NE tumor vaccine containing the synthetic peptide IKVAV-OVA257-264 (I-OVA) was prepared by a low-energy emulsification method. The combination of IKVAV and OVA257-264 can enhance antigen uptake by nasal mucosal epithelial cells. Here, we establish a protocol to study the physicochemical characteristics by transmission electron microscopy (TEM), atomic force microscopy (AFM), and dynamic light scattering (DLS); stability in the presence of mucin protein; toxicity by examining the cell viability of BEAS-2B cells and the nasal and lung tissues of C57BL/6 mice; cellular uptake by confocal laser scanning microscopy (CLSM); release profiles by imaging small animals in vivo; and the protective and therapeutic effect of the vaccine by using an E.G7 tumor-bearing model. We anticipate that the protocol will provide technical and theoretical clues for the future development of novel T cell epitope peptide mucosal vaccines.

A lipophilic chitosan-modified self-nanoemulsifying system influencing cellular membrane metabolism enhances antibacterial and anti-biofilm efficacy for multi-drug resistant Pseudomonas aeruginosa wound infection.

Wound infections, especially infections with multidrug-resistant bacteria, are a serious public health issue worldwide. In addition, the accumulation microbial biofilm of multidrug-resistant Pseudomonas aeruginosa increases the risk and physically obstruct its healing activity at the wound site. Therefore, the development of an eminent agent to control wound infection is urgently needed. Here, we report a novel chitosan (a natural biological macromolecule)-modified self-nanoemulsifying system (CSN) with lipophilic chlorhexidine acetate (CAA, a poorly water-soluble agent) that was designed and prepared using low-energy emulsification methods. We found that CSN displays better antibacterial efficacy, which occurs more quickly than its aqueous solution, in destroying the structure of the bacterial cell membrane and promoting the leakage of nucleic acids, proteins, K+, and Mg2+ from Pseudomonas aeruginosa cells. Importantly, CSN also accelerates skin wound healing after Pseudomonas aeruginosa infection by inhibiting biofilm formation and eradicating mature biofilms. Moreover, the proteomic results suggested that CSN altered membrane permeability and cellular membrane metabolism, allowing more drug molecules to enter the cytosol. Based on these results, this lipophilic self-nanoemulsifying system may be applied in the treatment of skin wounds caused by multidrug-resistant bacteria, especially Pseudomonas aeruginosa.

Preparation and characterization of patauá and pracaxi Brazilian vegetable oil emulsions

In this work, the stability of oil-in-water emulsions (O/W) of patauá (Oenocarpus bataua) and pracaxi (Pentaclethra macroloba) oils, both from Amazon rainforest, was investigated. Low-energy emulsification methods were used, such as Emulsion Inversion Point (EIP) and Phase Inversion Temperature (PIT), both based on the minimal interfacial surface, combined with optimized Hydrophilic-Lipophilic Balance (HLB). Phase inversion was determined by electrical conductivity measurements. The surfactants used were Span® 80, Tween® 20, Tween® 60, and Tween® 80. Surfactant mixtures of Span® 80 + Tween® 80 were the best samples prepared. The composition of the most stable samples was 80.00 wt% aqueous phase, 15.00 wt% nonionic surfactants, and 5.00 wt% oil phase (patauá or pracaxi oil). The samples with the best kinetic results were those prepared with the required HLB and PIT values of 12.86 and 84.05 °C, for patauá oil, and of 9.61 and 79.50 °C for pracaxi oil. The kinetic stability of the oil emulsions was characterized by creaming index (CI), by evolution over time of the droplet size, viscosity, and electric conductivity. The results showed that: (1) the droplet size distribution influenced electric conductivity; (2) the relative amount of surfactants Tween® and Span® used is more important to determine the physicochemical and interfacial properties of the emulsion than the oil identity itself; (3) it is crucial to pay attention to the influence of air bubbles—involuntarily inserted into the mixture during the emulsification process—in the physicochemical properties of the system. These conclusions can be extended to other oil-in-water emulsions.

Development of Nanoemulsion containing Centella Asiatica Crude Extract as a Promising Drug Delivery System for Epilepsy Treatment

Preparations of products containing herbal extracts have grown by leaps and bounds, hitting the pharmaceutical industries due to the natural healing approach. Centella asiatica L. (pegaga) (C. asiatica) is a famous plant commonly served as a salad in Asian diets. It contains various phytoconstituents, which plays a vital role in the treatment of various illness. For example, in the treatment of epilepsy, crossing the blood-brain barrier (BBB) has been a challenge (even as parenteral application) as not all the drugs were able to pass through the membrane and produce a maximum therapeutic effect to the targeted site of action. Thus, a nanoemulsion formulation containing C. asiatica crude extract needs to be developed to penetrate the BBB. This study aims to formulate a nanoemulsion containing crude extract of C. asiatica leaves for epilepsy treatment. Nanoemulsion was prepared by using low energy emulsification method. The particle size, polydispersity index (PDI), and zeta potential of C. asiatica crude extract nanoemulsion were found to be at 57.86 ± 0.03 nm, 0.50 ± 0.03, and -26.50 ± 0.03 mV, respectively. The formulation remained physically stable at different storage temperatures (4, 25, and 45 °C) for 90 days. The particle size observed by transmission electron microscopy (TEM) was shown to be at ̴50 nm, which correlated well with the Zetasizer analysis. The cytotoxicity study, conducted on formulated C. asiatica nanoemulsion towards Vero cell line and 3T3 cell line, showed that the IC50 value indicated that it is nontoxic (>500 µg/ml). C. asiatica nanoemulsion was found to be stable based on the good evidence of physicochemical properties, and the IC50 value indicates significance for future in vivo and in vitro studies based upon the route of administration.

Potential of quercetin in combination with antioxidants of different polarity incorporated in oil-in-water nanoemulsions to control enzymatic browning of apples

Quercetin in combination with other antioxidants from natural sources and different polarity, including quercetin-3-rhamnoside, ascorbic acid, and α-tocopherol, were incorporated into oil-in-water (O/W) nanoemulsions to evaluate their effects on the activity of polyphenol oxidase (PPO) and browning of Granny Smith apple fruits. Additionally, molecular modeling methods were used to determine the ability and possible mechanisms of action of quercetin and quercetin-3-rhamnoside to inhibit PPO and to reduce the o-quinones derived from (–)-epicatechin, chlorogenic acid, catechol and methylcatechol (PPO substrates). Nanoemulsions were prepared using a low-energy emulsification method. In all nanoemulsions, Dynamic Light Scattering (DLS) analysis showed a size distribution of droplets between 100 and 500 nm diameter, whereas microscopical observation by freeze-fracture transmission electron microscopy (FF-TEM) corroborated the presence of the droplets and their size. Also, occasional arrangements consisting of stacked layers, with vesicle-like structures between them, were seen. The nanoemulsion 1, that contained the four antioxidants was the one that showed the best effect on PPO, inhibiting it by 41%, and inhibiting the browning of the apple flesh between 81 and 74% in a period of 6 h. Calculations with molecular modeling methods suggest that quercetin may be a more effective reducing agent than ascorbic acid and quercetin-3-rhamnoside, and could also act as a non-competitive inhibitor of PPO. While quercetin-3-rhamnoside represents a selective and competitive inhibitor of PPO. The most important function of α-tocopherol in the nanoemulsions could be the regeneration of quercetin to prolong its antioxidant activity.

Preparation and Evaluation of In-vitro Release and Cytotoxicity of Indigofera zollingeriana Crude Leaf Extract-loaded Nanoemulsion

This study aimed to prepare and investigate the in-vitro release and cytotoxicity effect of an Indigofera zollingeriana crude leaf extract-loaded nanoemulsion formulation. Initially, I. zollingeriana leaf extract was extracted and the ternary phase diagram was constructed to select the nanoemulsion formulation. The nanoemulsion was prepared with a combination of oil, surfactant, and water using a low-energy emulsification method. The formulation was characterized according to droplet size, polydispersity, zeta potential, morphology, and physical stability. In-vitro release and cytotoxicity were investigated to determine the efficacy of the nanoemulsion. Based on the results, a stable formulation (no phase separation) with a ratio of 5:10:85 (sunflower seed oil: surfactant: water) was obtained with droplet size, polydispersity index (PDI) and zeta potential of 160.5 nm, 0.262 and -31.1 mV, respectively. Morphology study revealed that particles of the nanoemulsion were spherical with diameters ranging from 95.97 to 148.31 nm. In-vitro release study showed fast release in the first 3 h at pH 7.4. The percentage cumulative release of the crude extract was obtained by up to 86.50% for 24 h. Cytotoxicity study of the nanoemulsion formulation showed moderate and mild toxicity against lung cancer (A549) and breast cancer (MCF-7) cell lines, respectively.

Nanoemulsions containing Garcinia mangostana L. pericarp extract for topical applications: Development, characterization, and in vitro percutaneous penetration assay.

A highly stable oil-in-water nanoemulsion for topical applications, containing mangostins extracted from the pericarp of mangosteen (Garcinia mangostana L.), is a promising strategy to protect mangostins as well as to improve penetration of these important antioxidants through the skins. Nanoemulsions consisted of virgin coconut oil as the oil phase, Tween-80 and Span-80 as surfactants, and xanthan gum as the thickening agent, were prepared using the high-energy and low-energy emulsification methods. The nanoemulsions that were stable up to 28 days had oil droplet diameter of 220 nm to 353 nm and zeta potential of -46.9 mV to -63.7 mV. The accelerated stability test showed that the most stable nanoemulsions were those prepared using the low-energy emulsification method with an estimated shelf life of eleven months, composed of 11% oil phase, 17% surfactant, and 72% aqueous phase. The in vitro percutaneous penetration test for the nanoemulsion with added xanthan gum provided high cumulative skin penetration of mangostins of up to 114 μg/cm2. The results of this study indicate that virgin coconut oil-based nanoemulsions containing mangostins, prepared using the low-energy emulsification method, stabilized by xanthan gum and mixed at 40°C can prospectively be used for topical applications.

Transdermal Delivery of Capsaicin Nanoemulgel: Optimization, Skin Permeation and In Vivo Activity against Diabetic Neuropathy.

Purpose: Diabetic somatic neuropathy is one of the most prevalent complications in type 1 diabetes mellitus (T1D). Many treatments were investigated to alleviate the pain associated with this condition. Capsaicin is a naturally occurring lipophilic alkaloid that proved to be an effective and safe treatment of chronic painful disorders. Despite the known therapeutic benefits of capsaicin, the conventional topical formulations have limited bioavailability. Therefore, the current study aims to develop capsaicin nanoemulgel to increase skin permeation and enhance its activity against neuropathic pain. Methods: Low-energy emulsification method was used to prepare nanoemulsions, using eucalyptus oil as the oily phase, Tween 80 as a surfactant, propylene glycol, ethanol and isopropyl alcohol as co-surfactants. Pseudo-ternary phase diagrams were constructed to investigate and optimize the formulation. Subsequently, the optimum formulation was formulated as a nanoemulgel and investigated for, skin permeation using Franz diffusion cell, and diabetic neuropathy (DN) management using alloxan-induced diabetic mice. Results: The selected nanoemulsion containing 0.05% capsaicin is composed of 8 % oil, 24 % S mix (Tween 80: isopropyl alcohol 2:1 w/w) and 68 % water. It is characterized by nanosized globules (28.15 ± 0.24 nm) with a relatively low polydispersity index (0.27 ± 0.05). The nanoemulgel revealed circa 4-fold increase in capsaicin cumulative permeation when compared to the conventional gel, and an improvement in its antinociceptive properties was observed in the treated diabetic mice (P < 0.05). Conclusion: The selected capsaicin nanoemulgel would be a promising transdermal formulation that may alleviate diabetic neuropathy in T1D patients.