Nanoemulsion Processes Design and Applications

A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Pharmaceutical Processes".

Deadline for manuscript submissions: 20 July 2024 | Viewed by 34956

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Guest Editor
Department of Physical and Quantum Chemistry, Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
Interests: surfactants; disperse systems; nanoemulsions; lipid nanocarriers; polymeric nanocarriers; encapsulation/solubilization processes; colloids; colloidal stability; photodynamic therapy; theranostics
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Special Issue Information

Dear Colleagues,

Surface-active amphiphilic compounds, unique in their structure, allowing the dissolution of one compound in two different solvents, form micellar aggregates—so-called associated colloids—equipped with a number of interesting features. Between the revealed systems, an important role may be played by nanoemulsions, as kinetically stable formulations with a strongly developed external surface at a relatively small volume and viscosity. These bluish/translucent isotropic dispersions, which comprise nano-domains/droplets (with general sizes 20-500 nm) coexisting in high kinetic equilibrium due to the presence of the surfactant layer at the oil/water interface, represent particularly interesting aggregates due to their high loading capacity and application potential.

This Special Issue focusses on the recent progress in the design, engineering, and physicochemical evaluation of novel nanoemulsion formulations. It will include research papers and review articles reflecting the most recent development in this dynamic research area, including nanoemulsions processes by low- or high-energy approaches, colloidal stability, drug solubilisation/encapsulation, and rheology, which can depend on many control parameters such as composition, concentration, size, charge, structural features of surfactants/emulsifying agents, and properties of the liquid/liquid interface.

Dr. Urszula Bazylinska
Guest Editor

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Keywords

  • surfactants
  • low-energy methods
  • high-energy methods
  • colloidal stability
  • rheology
  • drug encapsulation/solubilisation

Published Papers (9 papers)

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Research

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20 pages, 6086 KiB  
Article
Identification and Mapping of Three Distinct Breakup Morphologies in the Turbulent Inertial Regime of Emulsification—Effect of Weber Number and Viscosity Ratio
by Andreas Håkansson, Peyman Olad and Fredrik Innings
Processes 2022, 10(11), 2204; https://doi.org/10.3390/pr10112204 - 26 Oct 2022
Cited by 3 | Viewed by 1552
Abstract
Turbulent emulsification is an important unit operation in chemical engineering. Due to its high energy cost, there is substantial interest in increasing the fundamental understanding of drop breakup in these devices, e.g., for optimization. In this study, numerical breakup experiments are used to [...] Read more.
Turbulent emulsification is an important unit operation in chemical engineering. Due to its high energy cost, there is substantial interest in increasing the fundamental understanding of drop breakup in these devices, e.g., for optimization. In this study, numerical breakup experiments are used to study turbulent fragmentation of viscous drops, under conditions similar to emulsification devices such as high-pressure homogenizers and rotor-stator mixers. The drop diameter was kept larger than the Kolmogorov length scale (i.e., turbulent inertial breakup). When varying the Weber number (We) and the disperse-to-continuous phase viscosity ratio in a range applicable to emulsification, three distinct breakup morphologies are identified: sheet breakup (large We and/or low viscosity ratio), thread breakup (intermediary We and viscosity ratio > 5), and bulb breakup (low We). The number and size of resulting fragments differ between these three morphologies. Moreover, results also confirm previous findings showing drops with different We differing in how they attenuate the surrounding turbulent flow. This can create ‘exclaves’ in the phase space, i.e., narrow We-intervals, where drops with lower We break and drops with higher We do not (due to the latter attenuating the surrounding turbulence stresses more). Full article
(This article belongs to the Special Issue Nanoemulsion Processes Design and Applications)
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8 pages, 1077 KiB  
Article
Relationship between Some Colloidal Properties of Non-Ionic-Anionic Surfactant Mixtures
by Roland Nagy, Réka Kothencz, Máté Hartyányi and László Bartha
Processes 2022, 10(6), 1136; https://doi.org/10.3390/pr10061136 - 06 Jun 2022
Cited by 1 | Viewed by 2239
Abstract
Non-ionic surfactants are compatible with different types of materials, therefore they can be applied in various packages. Fatty-acid derivates as non-ionic surfactants and their mixtures were investigated to study their colloidal behavior. The HLB value, the particle size, the emulsification capacity and the [...] Read more.
Non-ionic surfactants are compatible with different types of materials, therefore they can be applied in various packages. Fatty-acid derivates as non-ionic surfactants and their mixtures were investigated to study their colloidal behavior. The HLB value, the particle size, the emulsification capacity and the interfacial tension of various commercial, non-ionic surfactants, and their mixtures with sodium lauryl-ether-sulfate (SLES), were determined. The surfactant mixtures were prepared in different non-ionic: anionic surfactant ratios to examine their effect on several surfactant characteristics. The interfacial tension between the oil phase and aqueous phase was measured using the spinning drop method and the average hydrodynamic diameter of surfactants in the aqueous solution was determined using the dynamic light scattering method. The relationship between various colloidal properties of surfactants was investigated. It was found that there is a significant relationship between the colloidal characteristics and the structure of surfactants that can contribute to their efficient selection method. Full article
(This article belongs to the Special Issue Nanoemulsion Processes Design and Applications)
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15 pages, 2850 KiB  
Article
Paclitaxel and Myrrh oil Combination Therapy for Enhancement of Cytotoxicity against Breast Cancer; QbD Approach
by Tamer M. Shehata and Heba S. Elsewedy
Processes 2022, 10(5), 907; https://doi.org/10.3390/pr10050907 - 05 May 2022
Cited by 7 | Viewed by 1703
Abstract
Paclitaxel (PX), plant alkaloid, is a chemotherapeutic agent intended for treating a wide variety of cancers. The objective of the present study was to formulate and evaluate the anticancer activity of PX loaded into a nanocarrier, mainly PEGylated nanoemulsion (NE) fabricated with myrrh [...] Read more.
Paclitaxel (PX), plant alkaloid, is a chemotherapeutic agent intended for treating a wide variety of cancers. The objective of the present study was to formulate and evaluate the anticancer activity of PX loaded into a nanocarrier, mainly PEGylated nanoemulsion (NE) fabricated with myrrh essential oil. Myrrh essential oil has been estimated previously to show respectable anticancer activity. Surface modification of the formulation with PEG-DSPE would help in avoiding phagocytosis and prolong the residence time in blood circulation. Various NE formulations were developed after operating (22) factorial design, characterized for their particle size, in vitro release, and hemolytic activity. The optimized formula was selected and compared to its naked counterpart in respect to several characterizations. Quantitative amount of protein absorbed on the formulation surfaces and in vitro release with and without serum incubation were evaluated. Ultimately, MTT assay was conducted to distinguish the anti-proliferative activity. PEGylated PX-NE showed particle size 170 nm, viscosity 2.91 cP, in vitro release 57.5%, and hemolysis 3.44%, which were suitable for intravenous administration. A lower amount of serum protein adsorbed on PEGylated PX-NE surface (16.57 µg/µmol) compared to naked counterpart (45.73 µg/µmol). In vitro release from PEGylated NE following serum incubation was not greatly affected (63.3%), in contrast to the naked counterpart (78.8%). Eventually, anti-proliferative effect was obtained for PEGylated PX-NE achieving IC50 38.66 µg/mL. The results obtained recommend PEGylated NE of myrrh essential oil as a candidate nanocarrier for passive targeting of PX. Full article
(This article belongs to the Special Issue Nanoemulsion Processes Design and Applications)
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15 pages, 1677 KiB  
Article
Coating of Tomatoes (Solanum lycopersicum L.) Employing Nanoemulsions Containing the Bioactive Compounds of Cactus Acid Fruits: Quality and Shelf Life
by Elizabeth Pérez-Soto, Kenia Idalid Badillo-Solis, Antonio de Jesús Cenobio-Galindo, Juan Ocampo-López, Fanny Emma Ludeña-Urquizo, Abigail Reyes-Munguía, Sergio Rubén Pérez-Ríos and Rafael Campos-Montiel
Processes 2021, 9(12), 2173; https://doi.org/10.3390/pr9122173 - 02 Dec 2021
Cited by 1 | Viewed by 2306
Abstract
This study was aimed at evaluating the effect of a nanoemulsion containing the bioactive compounds of orange essential oil and xoconostle (Opuntia oligacantha C.F. Först) on maintaining and improving the quality of the shelf life of tomato fruits. The nanoemulsion was applied [...] Read more.
This study was aimed at evaluating the effect of a nanoemulsion containing the bioactive compounds of orange essential oil and xoconostle (Opuntia oligacantha C.F. Först) on maintaining and improving the quality of the shelf life of tomato fruits. The nanoemulsion was applied as a coating on the whole fruits during physiological maturity; the treatments were thus: Control 1 without coating (C1); Control 2 with food-grade mineral oil coating (C2); and nanoemulsions that were diluted with mineral oil at 2.5% (DN2.5), 5% (DN5), 10% (DN10), and 20% (DN20). Further, the following parameters were determined for 21 days: the percentage weight loss, firmness, colour, pH, titratable acidity, total soluble solids, ascorbic acid content, total phenols, flavonoids, tannins, antioxidant activities DPPH and ABTS, and the histological evaluation of the pericarp of the fruits. Significant differences (p < 0.05) were observed during the treatments; DN10 and DN20 obtained the best weight loss results (3.27 ± 0.31% and 3.71 ± 0.30%, respectively) compared with C1 and C2. The DN5 and DN20 textures exhibited the highest firmness (11.56 ± 0.33 and 11.89 ± 1.04 N, respectively). The antioxidant activity (DPPH on Day 21) was higher in the DN20 treatment (48.19 ± 0.95%) compared with in C1 (39.52 ± 0.30%) and C2 (38.14 ± 0.76%). Histological evaluation revealed that the nanoemulsion coating allowed a slower maturation of the cells in the pericarp of the fruits. The nanoemulsion, as a coat, improved the quality and valuable life of the tomato regarding its physicochemical and antioxidant properties, thus availing an effective alternative for conserving this fruit. Full article
(This article belongs to the Special Issue Nanoemulsion Processes Design and Applications)
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14 pages, 1263 KiB  
Article
Comparative Study of Physicochemical Properties of Nanoemulsions Fabricated with Natural and Synthetic Surfactants
by Karen Fuentes, Claudia Matamala, Nayaret Martínez, Rommy N. Zúñiga and Elizabeth Troncoso
Processes 2021, 9(11), 2002; https://doi.org/10.3390/pr9112002 - 09 Nov 2021
Cited by 21 | Viewed by 3625
Abstract
This work aims to evaluate the effect of two natural (whey protein isolate, WPI, and soy lecithin) and a synthetic (Tween 20) emulsifier on physicochemical properties and physical stability of food grade nanoemulsions. Emulsions stabilized by these three surfactants and different sunflower oil [...] Read more.
This work aims to evaluate the effect of two natural (whey protein isolate, WPI, and soy lecithin) and a synthetic (Tween 20) emulsifier on physicochemical properties and physical stability of food grade nanoemulsions. Emulsions stabilized by these three surfactants and different sunflower oil contents (30% and 50% w/w), as the dispersed phase, were fabricated at two levels of homogenization pressure (500 and 1000 bar). Nanoemulsions were characterized for droplet size distribution, Zeta-potential, rheological properties, and physical stability. Dynamic light scattering showed that droplet size distributions and D50 values were strongly affected by the surfactant used and the oil content. WPI gave similar droplet diameters to Tween 20 and soy lecithin gave the larger diameters. The rheology of emulsions presented a Newtonian behavior, except for WPI-stabilized emulsions at 50% of oil, presenting a shear-thinning behavior. The physical stability of the emulsions depended on the surfactant used, with increasing order of stability as follows: soy lecithin < Tween 20 < WPI. From our results, we conclude that WPI is an effective natural replacement of synthetic surfactant (Tween 20) for the fabrication of food-grade nanoemulsions. Full article
(This article belongs to the Special Issue Nanoemulsion Processes Design and Applications)
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11 pages, 1581 KiB  
Article
Influence of Process Design on the Preparation of Solid Lipid Nanoparticles by an Ultrasonic-Nanoemulsification Method
by Agata Pucek-Kaczmarek
Processes 2021, 9(8), 1265; https://doi.org/10.3390/pr9081265 - 22 Jul 2021
Cited by 10 | Viewed by 2789
Abstract
In recent years, lipid-based nanosystems have emerged as a promising class of nanocarriers for encapsulating many active agents. Solid lipid nanoparticles (SLNs) provide good stability (colloidal as well as physical) and high biocompatibility. Appropriate design of the carrier structure through a selection of [...] Read more.
In recent years, lipid-based nanosystems have emerged as a promising class of nanocarriers for encapsulating many active agents. Solid lipid nanoparticles (SLNs) provide good stability (colloidal as well as physical) and high biocompatibility. Appropriate design of the carrier structure through a selection of components and preparation methods allows us to obtain formulations with desired physicochemical parameters and biological properties. The present contribution has been carried out to investigate SLNs containing biocompatible phosphatidylcholine mixed with non-ionic surfactant Tween 60 as stabilizing agents. The internal lipid phase consisted of glyceryl monostearate was confirmed as safe for drug delivery by the Food and Drug Administration. The SLNs were fabricated by ultrasonic-nanoemulsification method. The preparation process was optimized in regard to variable parameters such as ultrasonication time and used amplitude and number of cycles. The sizes of the studied nanoparticles along with the size distribution were determined by dynamic light scattering (DLS), while shape and morphology were determined by atomic force microscopy (AFM) and transmission electron microscopy (TEM). The colloidal stability was measured by a turbidimetric method. The physical state of SLNs was characterized using differential scanning calorimetry (DSC). The obtained results indicate that the proposed SLNs may provide great potential for design and preparation of novel delivery nanosystems with a variety of possible applications. Full article
(This article belongs to the Special Issue Nanoemulsion Processes Design and Applications)
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13 pages, 12603 KiB  
Article
Optimizing the Process Design of Oil-in-Water Nanoemulsion for Delivering Poorly Soluble Cannabidiol Oil
by Agnieszka Lewińska
Processes 2021, 9(7), 1180; https://doi.org/10.3390/pr9071180 - 07 Jul 2021
Cited by 17 | Viewed by 6342
Abstract
Process approaches and intensification technological processes are integrated parts of available devices, which have a positive effect on the parameters of the obtained products. Nanoemulsions as delivery carriers are becoming more popular and there is a real need to increase the possibilities of [...] Read more.
Process approaches and intensification technological processes are integrated parts of available devices, which have a positive effect on the parameters of the obtained products. Nanoemulsions as delivery carriers are becoming more popular and there is a real need to increase the possibilities of formulation designing and engineering. Therefore, preparations of oil-in-water nanoemulsion with encapsulated cannabidiol (CBD) as oil phase were carried out in two ways: sonication method and two-stage high-pressure homogenization. The provided analysis showed spherical morphology and much larger sizes and polydispersity of nanoemulsions obtained by the sonication approach. The size of nanodroplets was from 216 nm up to 1418 nm for sonication, whereas for homogenization 128–880 nm. Additionally, it was observed that a proportionally higher percentage of surfactin resulted in a higher value of the Zeta potential. The formulations were found to be stable for at least 30 days. The in vitro experiments performed on human skin cell lines (HaCaT keratinocytes and normal dermal NHDF fibroblasts), and in vivo topical tests on probants established the biocompatibility of nanoemulsions with CBD. The last stage exhibits reduced discoloration and a higher degree of hydration by the selected systems with CBD and, thus indicating this nanoformulation as useful in cosmetics applications. Full article
(This article belongs to the Special Issue Nanoemulsion Processes Design and Applications)
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26 pages, 3063 KiB  
Article
Nanoemulsion Gel Formulation Optimization for Burn Wounds: Analysis of Rheological and Sensory Properties
by Małgorzata Miastkowska, Agnieszka Kulawik-Pióro and Mariola Szczurek
Processes 2020, 8(11), 1416; https://doi.org/10.3390/pr8111416 - 06 Nov 2020
Cited by 28 | Viewed by 6499
Abstract
Background: Despite the variety of treatment methods for wounds and scars after burns, there are still few effective preparations that can be used in a non-invasive therapy. Recent years have seen significant development of nanomedicine and nanotechnology in the treatment of infection in [...] Read more.
Background: Despite the variety of treatment methods for wounds and scars after burns, there are still few effective preparations that can be used in a non-invasive therapy. Recent years have seen significant development of nanomedicine and nanotechnology in the treatment of infection in burn wounds. Proposal: The aim of this work was to develop a formula of a nanoemulsion gel for skin regeneration after burns, and to compare its rheological and sensory properties, as well as the effectiveness of post-burn skin regeneration with preparations available on the market. Methods: At the first stage of studies the composition and parameters of the preparation of sea buckthorn oil-based O/W (oil-in-water) nanoemulsion containing hyaluronic acid and aloe vera gel, as the active ingredients were optimized. Then, the nanoemulsion was added to the gel matrix composed of carbomer (1%) and water which resulted in receiving nanoemulgel. The physicochemical parameters of the obtained samples were characterized by means of dynamic light scattering method and scanning electron microscope. Rheological, sensory and influence on skin condition analysis was conducted for selected market products and developed nanoemulgel. Results: Nanoemulsion gel (d = 211 ± 1.4 nm, polydispersity index (PDI) = 0.205 ± 0.01) was characterized by semi-solid, non-sticky consistency, porous structure, law viscosity, good “primary” and “secondary” skin feelings and pleasant sensorical properties. It improves the condition of burned skin by creating a protective layer on the skin and increasing the hydration level. Conclusion: Due to the fact that the obtained nanoemulsion gel combines the advantages of an emulsion and a gel formulation, it can be a promising alternative to medical cosmetics available on the market, as a form of formulation used in skin care after burns. Full article
(This article belongs to the Special Issue Nanoemulsion Processes Design and Applications)
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Review

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42 pages, 6282 KiB  
Review
Versatility of Reverse Micelles: From Biomimetic Models to Nano (Bio)Sensor Design
by Melania-Liliana Arsene, Iuliana Răut, Mariana Călin, Maria-Luiza Jecu, Mihaela Doni and Ana-Maria Gurban
Processes 2021, 9(2), 345; https://doi.org/10.3390/pr9020345 - 13 Feb 2021
Cited by 36 | Viewed by 6289
Abstract
This paper presents an overview of the principal structural and dynamics characteristics of reverse micelles (RMs) in order to highlight their structural flexibility and versatility, along with the possibility to modulate their parameters in a controlled manner. The multifunctionality in a large range [...] Read more.
This paper presents an overview of the principal structural and dynamics characteristics of reverse micelles (RMs) in order to highlight their structural flexibility and versatility, along with the possibility to modulate their parameters in a controlled manner. The multifunctionality in a large range of different scientific fields is exemplified in two distinct directions: a theoretical model for mimicry of the biological microenvironment and practical application in the field of nanotechnology and nano-based sensors. RMs represent a convenient experimental approach that limits the drawbacks of the conventionally biological studies in vitro, while the particular structure confers them the status of simplified mimics of cells by reproducing a complex supramolecular organization in an artificial system. The biological relevance of RMs is discussed in some particular cases referring to confinement and a crowded environment, as well as the molecular dynamics of water and a cell membrane structure. The use of RMs in a range of applications seems to be more promising due to their structural and compositional flexibility, high efficiency, and selectivity. Advances in nanotechnology are based on developing new methods of nanomaterial synthesis and deposition. This review highlights the advantages of using RMs in the synthesis of nanoparticles with specific properties and in nano (bio)sensor design. Full article
(This article belongs to the Special Issue Nanoemulsion Processes Design and Applications)
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