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Influence of Curcuma Longa extract in citral addition on functional properties of thin films with triple-layer structure based on furcellaran and gelatin. Int J Biol Macromol 2024; 266:131344. [PMID: 38574923 DOI: 10.1016/j.ijbiomac.2024.131344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/23/2024] [Accepted: 04/01/2024] [Indexed: 04/06/2024]
Abstract
In this study, we obtained triple-layer films based on furcellaran and gelatin, in which the middle layer was enriched with extract of Curcuma longa in citral. This newly developed material underwent a comprehensive characterisation process to identify significant improvements in its functional properties. Both SEM, XRD and FTIR analyzes indicated the formation of interactions not only between the components but also between the film layers. Notably, the incorporation of the natural extract led to a significant reduction in solubility, decreasing it from 74.79 % to 57.25 %, while enhancing thermal stability expressed as a melting point elevating it from 147.10 °C in the control film to 158.80 °C in the film with the highest concentration of the active ingredient. Simultaneously, the addition of this active ingredient resulted in decreased water contact angle (WCA) values, rendering the film more hydrophilic. The produced films exhibit great promise as packaging materials, particularly within the food industry, and the conducted research is marked by its forward-looking and developmental approach.
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Aromas: Lovely to Smell and Nice Solvents for Polyphenols? Curcumin Solubilisation Power of Fragrances and Flavours. Molecules 2024; 29:294. [PMID: 38257207 PMCID: PMC10820666 DOI: 10.3390/molecules29020294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/22/2023] [Accepted: 12/25/2023] [Indexed: 01/24/2024] Open
Abstract
Natural aromas like cinnamaldehyde are suitable solvents to extract curcuminoids, the active ingredients found in the rhizomes of Curcuma longa L. In a pursuit to find other nature-based solvents, capable of solving curcumin, forty fragrances and flavours were investigated in terms of their solubilisation power. Aroma compounds were selected according to their molecular structure and functional groups. Their capabilities of solving curcumin were examined by UV-Vis spectroscopy and COSMO-RS calculations. The trends of these calculations were in accordance with the experimental solubilisation trend of the solubility screening and a list with the respective curcumin concentrations is given; σ-profiles and Gibbs free energy were considered to further investigate the solubilisation process of curcumin, which was found to be based on hydrogen bonding. High curcumin solubility was achieved in the presence of solvent (mixtures) with high hydrogen-bond-acceptor and low hydrogen-bond-donor abilities, like γ- and δ-lactones. The special case of DMSO was also examined, as the highest curcumin solubility was observed with it. Possible specific interactions of selected aroma compounds (citral and δ-hexalactone) with curcumin were investigated via 1H NMR and NOESY experiments. The tested flavours and fragrances were evaluated regarding their potential as green alternative solvents.
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3
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In-depth study of binary ethanol-triacetin mixtures in relation to their excellent solubilization power. Phys Chem Chem Phys 2023. [PMID: 37490278 DOI: 10.1039/d3cp02716c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
A significant synergistic effect is observed when solubilizing curcumin or tetrahydrocurcumin in binary mixtures of ethanol and triacetin. The present work deals with a detailed investigation of the solvent system by means of COSMO-RS-based calculations, dynamic light scattering, small-and-wide-angle X-ray scattering, and dielectric relaxation spectroscopy. Theoretical calculations lead to the conclusion that the enhanced solubility is not primarily the result of an interaction optimum between individual surface charge densities. Scattering experiments also exclude the formation of mesoscopic structures as the main reason. However, dielectric relaxation spectra suggest that in the concentration range of 0.3 ≤ x(triacetin) ≤ 0.6, ethanol molecules are released from their living polymer ethanol network and can interact with triacetin on a molecular level. The mesoscopic aggregation, thus, decreases. The concentration range of the ethanol-triacetin complexes has a significant overlap with the range of maximum solubility of (tetrahydro)curcumin. Nevertheless, despite detailed investigations, the exact origin of the solubilization power of the solvent remains speculative.
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4
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Novel green production of natural-like vanilla extract from curcuminoids. Food Chem 2023; 417:135944. [PMID: 36934704 DOI: 10.1016/j.foodchem.2023.135944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 03/08/2023] [Accepted: 03/10/2023] [Indexed: 03/17/2023]
Abstract
The demand for natural vanilla extract, and vanillin in particular, by far exceeds the current production, as both the cultivation of vanilla beans and the extraction of vanillin are laborious. For this purpose, most vanillin used today is produced synthetically, contrary to the general trend toward bio-based products. The present study deals with the synthesis of nature-based vanillin, starting with the more accessible rhizomes of the plant Curcuma longa. Besides vanillin, vanillic acid and p-hydroxybenzaldehyde are synthesized that way, which are also found in the natural vanilla bean. The extraction of the curcuminoids and, finally, their conversion to the flavors are performed using visible light and food-grade chemicals only. A binary mixture of ethanol and triacetin, as well as a surfactant-free microemulsion consisting of water, ethanol, and triacetin, are investigated in this context. The results exceed the literature values for Soxhlet extraction of vanilla beans by a factor > 7.
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Investigation of the salting-in/-out, hydrotropic and surface-active behavior of plant-based hormone and phenolic acid salts. J Colloid Interface Sci 2023; 641:631-642. [PMID: 36963256 DOI: 10.1016/j.jcis.2023.03.077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 03/07/2023] [Accepted: 03/10/2023] [Indexed: 03/17/2023]
Abstract
HYPOTHESIS The role of hormones and polyphenolic acids in communication and regulation of biological processes can be linked to their physical-chemical interaction with target compounds and water. Further, the variety of polyphenolic acids suggests adjustable hydrotropic properties of these natural compounds. EXPERIMENTS Phase transition temperature (PTT) measurements of binary water/di(propylene glycol) n-propyl ether (DPnP) or propylene glycol n-propyl ether (PnP) systems with sodium dehydroepiandrosterone sulfate (NaDHEAS), indole-3-acetate (NaIAA), indole-3-butyrate (NaIBA) - common hormones -, and sodium polyphenolates should unravel their salting-in/-out properties. Their salting-in/-out behavior was compared to the compounds' surface-active and structuring properties via surface tension, dynamic light scattering (DLS) and Nuclear magnetic resonance (NMR) experiments. FINDINGS All hormone salts were revealed as salting-in agents. PTT, surface tension and DLS measurements indicated surfactant-like behavior of the hormone NaDHEAS, and hydrotropic behavior of NaIAA and NaIBA. The salting-in/-out properties of sodium polyphenolates - in an (anti-)hydrotrope range - are adjustable with functional groups. The (i) absence of nano-structuring in pure water, (ii) the reduction of the DPnP nano-structuring in water in presence of sodium polyphenolates and (iii) the absence of a slope change of the PTT curves at the critical aggregation concentration showed that the DPnP/polyphenolate interactions are of molecular hydrotropic and not of micellar/aggregative nature.
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6
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Enforced Electronic‐Donor‐Acceptor Complex Formation in Water for Photochemical Cross‐Coupling. Angew Chem Int Ed Engl 2023. [DOI: 10.1002/ange.202303073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
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7
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Enforced Electronic‐Donor‐Acceptor Complex Formation in Water for Photochemical Cross‐Coupling. Angew Chem Int Ed Engl 2023. [DOI: 10.1002/anie.202303073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
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8
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Enforced Electronic-Donor-Acceptor Complex Formation in Water for Photochemical Cross-Coupling. Angew Chem Int Ed Engl 2023; 62:e202218775. [PMID: 36735337 DOI: 10.1002/anie.202218775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/02/2023] [Accepted: 02/03/2023] [Indexed: 02/04/2023]
Abstract
The amino alcohol meglumine solubilizes organic compounds in water and enforces the formation of electron donor acceptor (EDA) complexes of haloarenes with indoles, anilines, anisoles or thiols, which are not observed in organic solvents. UV-A photoinduced electron transfer within the EDA complexes induces the mesolytic cleavage of the halide ion and radical recombination of the arenes leading, after rearomatization and proton loss to C-C or C-S coupling products. Depending on the substitution pattern selective and unique cross-couplings are observed. UV and NMR measurements reveal the importance of the assembly for the photoinduced reaction. Enforced EDA aggregate formation in water allows new activation modes for organic photochemical synthesis.
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Enhancement of Water Solubilization of Quercetin by Meglumine and Application of the Solubilization Concept to a Similar System. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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10
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Counterion effect on α-Keggin polyoxometalates in water: The peculiar role of H+ on their salting-in effect and co-assembly with organics. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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11
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Development of a fully water-dilutable mint concentrate based on a food-approved microemulsion. Food Chem 2022; 372:131230. [PMID: 34627088 DOI: 10.1016/j.foodchem.2021.131230] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 08/26/2021] [Accepted: 09/23/2021] [Indexed: 01/21/2023]
Abstract
Mentha spicata L. disappears in winter. The lack of fresh mint during the cold season can be a limiting factor for the preparation of mint tea. A fresh taste source that can be kept during winter is mint essential oil. As the oil is not soluble in water, a food-approved, water-soluble essential oil microemulsion was studied, investigating different surfactants, in particular Tween® 60. The challenge was to dissolve an extremely hydrophobic essential oil in a homogeneous, stable, transparent, and spontaneously forming solution of exclusively edible additives without adulterating the original fresh taste of the mint. Making use of the microemulsions' water and oil pseudo-phases, hydrophilic sweeteners and hydrophobic dyes could be incorporated to imitate mint leaf infusions aromatically and visually. The resulting formulation was a concentrate, consisting of ∼ 90% green components, which could be diluted with water or tea to obtain a beverage with a pleasant minty taste.
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12
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Phosphorylated resveratrol as a protein aggregation suppressor in vitro and in vivo. RSC Chem Biol 2022; 3:250-260. [PMID: 35360889 PMCID: PMC8826510 DOI: 10.1039/d1cb00220a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 12/26/2021] [Indexed: 01/16/2023] Open
Abstract
The stability of proteins in solution poses a great challenge for both technical applications and molecular biology, including neurodegenerative diseases. In this work, a phosphorylated resveratrol material was examined for its anti-aggregation properties in vitro and in vivo. Here, an anti-fibrillation effect could be measured for amyloid beta and human insulin in vitro and general anti-aggregation properties for crude chicken egg white in solution. Using a drosophila fly model for the overexpression of amyloid beta protein, changes in physiological protein aggregation and improved locomotor abilities could be observed in the presence of dietary phosphorylated resveratrol. Phosphorylated resveratrol can prevent the aggregation of globular and intrinsically disordered proteins in vitro and in vivo.![]()
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13
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Unexpected molecular dynamics of ethanol in hydrogen-bonded binary mixtures, ethanol-octanol and ethanol-water. EPJ WEB OF CONFERENCES 2022. [DOI: 10.1051/epjconf/202227201003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In view of getting a quantitative picture of the dynamics in mixtures of hydrogen-bonded liquids, in particular the ternary water-ethanol-octanol, we examine in this paper the dynamics of two binary systems: ethanol-water and ethanol-octanol. Our multiscale investigation includes quasi-elastic neutron scattering for the characterization of the dynamics at the molecular scale, completed by NMR at the mesoscopic scale and eventually compared with macroscopic viscosity properties. We highlight the decrease of diffusivity in pure alcohols when increasing the lengthscale and conjecture its relation with the two processes measured in dielectric spectroscopy. While the behaviour of ethanol-water is well understood, unexpected inversion of the slowest component between the micro and the mesoscale are evidenced in the ethanol-octanol mixture. This effect could be at the origin of the negative viscosity excess in the mixture of alcohols.
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14
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Extraction of curcumin from Curcuma longa using meglumine and pyroglutamic acid, respectively, as solubilizer and hydrotrope. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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15
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Triple role of sodium salicylate in solubilization, extraction, and stabilization of curcumin from Curcuma longa. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115538] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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16
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Self-assembly of a short amphiphile in water controlled by superchaotropic polyoxometalates: H4SiW12O40 vs. H3PW12O40. J Colloid Interface Sci 2021; 587:347-357. [DOI: 10.1016/j.jcis.2020.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/30/2020] [Accepted: 12/01/2020] [Indexed: 01/28/2023]
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17
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NADES-based surfactant-free microemulsions for solubilization and extraction of curcumin from Curcuma Longa. Food Chem 2021; 355:129624. [PMID: 33799268 DOI: 10.1016/j.foodchem.2021.129624] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 02/19/2021] [Accepted: 03/13/2021] [Indexed: 10/21/2022]
Abstract
A choline chloride + lactic acid (1:1) natural deep eutectic solvent (NADES) is used as an adjuvant to ethanol/triacetin mixtures to solubilize and extract curcumin from Curcuma Longa. The obtained NADES/ethanol/triacetin mixtures are homogeneous, transparent and of low viscosity even in the absence of water. Dynamic light scattering revealed significant nanostructures, typical of surfactant-free microemulsions. A twofold increase of curcumin solubility and remarkable extraction power (yield of ~90%) can be achieved in the ternary system including the NADES, although curcumin is hydrophobic and the used NADES are very polar. Due to the elevated solubility of curcumin, more extraction cycles can be made than in the previously published aqueous systems with the same amount of solution. As a result, less solvent is required to achieve the same extraction yield.
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Salting-in and salting-out effects of short amphiphilic molecules: a balance between specific ion effects and hydrophobicity. Phys Chem Chem Phys 2021; 23:1381-1391. [DOI: 10.1039/d0cp05491g] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Salting-in or salting-out tendencies depend on a balance between headgroup-specific ion effects and the hydrophobicity of the tail.
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19
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Curcumin extracts from Curcuma Longa - Improvement of concentration, purity, and stability in food-approved and water-soluble surfactant-free microemulsions. Food Chem 2020; 339:128140. [PMID: 33152894 DOI: 10.1016/j.foodchem.2020.128140] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/15/2020] [Accepted: 09/16/2020] [Indexed: 02/07/2023]
Abstract
Curcumin was extracted from Curcuma Longa employing a green, bio-based, and food-agreed surfactant-free microemulsion (SFME) consisting of water, ethanol, and triacetin. Concerning the high solubility of curcumin in the examined ternary mixtures, it was attempted to produce highly concentrated tinctures of up to a total of ~130 mg/mL curcuminoids in the solvent by repeatedly extracting fresh rhizomes in the same extraction mixture. The amount of water had a significant influence on the number of cycles that could be performed as well as on the extraction of the different curcuminoids. In addition, the purity of single extracts was enhanced to 94% by investigating several purification steps, e.g. vacuum distillation and lyophilization. Through purification before extraction, the water insoluble curcumin extract could be solubilized indefinitely in an aqueous environment. Additional stability tests showed that solutions of curcumin can be stable up to five months when concealed from natural light.
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20
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Pre-nucleation cluster formation upon ethyl acetate addition to an aqueous solution of an anionic hydrotrope. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113240] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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21
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Ab initio prediction of structuring/mesoscale inhomogeneities in surfactant-free microemulsions and hydrogen-bonding-free microemulsions. Phys Chem Chem Phys 2019; 21:8054-8066. [DOI: 10.1039/c8cp07544a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Prediction of microemulsion-like structuring in surfactant-free and hydrogen-bonding-free systems.
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22
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Enzyme activity of horseradish peroxidase in surfactant-free microemulsions. J Colloid Interface Sci 2018; 516:466-475. [DOI: 10.1016/j.jcis.2018.01.077] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 01/22/2018] [Accepted: 01/22/2018] [Indexed: 11/28/2022]
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23
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Salting-out and salting-in effects of organic compounds and applications of the salting-out effect of Pentasodium phytate in different extraction processes. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.03.091] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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24
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PPh4Cl in aqueous solution – the aggregation behavior of an antagonistic salt. Phys Chem Chem Phys 2017; 19:25463-25470. [DOI: 10.1039/c7cp02677c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The aggregation behavior of the antagonistic salt PPh4Cl was investigated. This salt was found to be an excellent hydrotrope which does not aggregate in binary aqueous solutions or in a ternary one, upon the addition of the exemplary hydrophobic molecule DR-13.
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25
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The impact of the structuring of hydrotropes in water on the mesoscale solubilisation of a third hydrophobic component. Phys Chem Chem Phys 2017; 19:1806-1816. [DOI: 10.1039/c6cp06696h] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The complex structuring of alcohols in water influences the mesoscale solubilisation of a third component depending on its nature.
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26
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A systematic study of the influence of mesoscale structuring on the kinetics of a chemical reaction. Phys Chem Chem Phys 2017; 19:23773-23780. [DOI: 10.1039/c7cp02134h] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this contribution, we link the mesoscopic structuring of the binary structured solvent mixture H2O/tert-butanol (TBA) to the kinetics and efficacy of the oxidation of benzyl alcohol (BA) to the corresponding aldehyde catalyzed by H5PMo10V2O40.
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Surfactant-free microemulsion electrokinetic chromatography (SF-MEEKC) with UV and MS detection - a novel approach for the separation and ESI-MS detection of neutral compounds. Anal Bioanal Chem 2016; 408:8681-8689. [PMID: 27866256 DOI: 10.1007/s00216-016-0057-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 10/14/2016] [Accepted: 10/24/2016] [Indexed: 11/25/2022]
Abstract
Microemulsion electrokinetic chromatography (MEEKC) is a powerful tool to separate neutral species based on differences in their hydrophobic and hydrophilic properties. However, as a major drawback the conventionally used SDS based microemulsions are not compatible with electrospray ionization mass spectrometry (ESI-MS). In this work, a surfactant-free microemulsion (SFME) consisting of water, ethanol, and 1-octanol is used for surfactant-free microemulsion electrokinetic chromatography (SF-MEEKC). Ammonium acetate was added to the SFME enabling electrophoretic separations. The stability of SFMEs containing ammonium acetate was investigated using small-angle X-ray scattering and dynamic light scattering. A method for the separation of a model system of hydrophobic and hydrophilic neutral vitamins, namely the vitamins B2 and D3, and the cationic vitamin B1 was developed using UV/VIS detection. The influence of the ammonium acetate concentration on the separation performance was studied in detail. The method was characterized concerning reproducibility of migration times and peak areas and concerning the linearity of the calibration data. Furthermore, SF-MEEKC was coupled to ESI-MS investigating the compatibility between SFMEs and the ESI process. The signal intensities of ESI-MS measurements of the model analytes were comparable for SFMEs and aqueous systems. Finally, the vitamin D3 content of a drug treating vitamin D3 deficiency was determined by SF-MEEKC coupled to ESI-MS using 25-hydroxycholecalciferol as an internal standard. Graphical abstract The concept of surfactant-free microemulsion electrokinetic chromatography coupled to electrospray ionization mass spectrometry.
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A renaissance of soaps? - How to make clear and stable solutions at neutral pH and room temperature. Adv Colloid Interface Sci 2016; 236:28-42. [PMID: 27476328 DOI: 10.1016/j.cis.2016.07.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 07/14/2016] [Accepted: 07/14/2016] [Indexed: 01/06/2023]
Abstract
Soaps are the oldest and perhaps most natural surfactants. However, they lost much of their importance since "technical surfactants", usually based on sulfates or sulfonates, have been developed over the last fifty years. Indeed, soaps are pH- and salt-sensitive and they are irritant, especially to the eyes. In food emulsions, although authorized, they have a bad taste, and long-chain saturated soaps have a high Krafft temperature. We believe that most or perhaps all of these problems can be solved with modern formulation approaches. We start this paper with a short overview of our present knowledge of soaps and soap formulations. Then we focus on the problem of the lacking soap solubility at neutral pH values. For example, it is well known that with the food emulsifier sodium oleate (NaOl), clear and stable aqueous solutions can only be obtained at pH values higher than 10. A decrease in the pH value leads to turbid and unstable solutions. This effect is not compatible with the formulation of aqueous stable and drinkable formulations with neutral or even acidic pH values. However, the pH value/phase behavior of aqueous soap solutions can be altered by the addition of other surfactants. Such a surfactant can be Rebaudioside A (RebA), a steviol glycoside from the plant Stevia rebaudiana which is used as a natural food sweetener. In a recent paper, we showed the influence of RebA on the apKa value of sodium oleate in a beverage microemulsion and on its clearing temperature. In the present paper, we report on the effect of the edible bio-surfactant RebA, on the macroscopic and microscopic phase behavior of simple aqueous sodium oleate solutions at varying pH values. The macroscopic phase behavior is investigated by visual observation and turbidity measurements. The microscopic phase behavior is analyzed by acid-base titration curves, phase-contrast and electron microscopy. It turned out that even at neutral pH, aqueous NaOl/RebA solutions can be completely clear and stable for more than 50days at room temperature. This is for the first time that a long chain soap could be really solubilized in water at neutral pH at room temperature. At last, these findings were applied to prepare stable, highly translucent and drinkable aqueous solutions of omega-3-fatty acids at a pH value of 7.5.
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29
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Antioxidant activity of hydro distillation water residues from Rosmarinus officinalis L. leaves determined by DPPH assays. CR CHIM 2016. [DOI: 10.1016/j.crci.2015.12.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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30
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How to explain microemulsions formed by solvent mixtures without conventional surfactants. Proc Natl Acad Sci U S A 2016; 113:4260-5. [PMID: 27044068 PMCID: PMC4843454 DOI: 10.1073/pnas.1515708113] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Ternary solutions containing one hydrotrope (such as ethanol) and two immiscible fluids, both being soluble in the hydrotrope at any proportion, show unexpected solubilization power and allow strange but yet unexplained membrane enzyme activity. We study the system ethanol-water-octanol as a simple model of such kinds of ternary solutions. The stability of "detergentless" micelles or microemulsions in such mixtures was proposed in the pioneering works of Barden and coworkers [Smith GD, Donelan CE, Barden RE (1977)J Colloid Interface Sci60(3):488-496 and Keiser BA, Varie D, Barden RE, Holt SL (1979)J Phys Chem83(10):1276-1281] in the 1970s and then, neglected, because no general explanation for the observations was available. Recent direct microstructural evidence by light, X-ray, and neutron scattering using contrast variation reopened the debate. We propose here a general principle for solubilization without conventional surfactants: the balance between hydration force and entropy. This balance explains the stability of microemulsions in homogeneous ternary mixtures based on cosolvents.
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The Nanostructure Studies of Surfactant-Free-Microemulsions in Fragrance Tinctures. Acta Chim Slov 2016; 63:138-43. [PMID: 26970798 DOI: 10.17344/acsi.2015.2037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
As it was shown recently that nanostructures can exist in water-ethanol-citronellol tinctures, a deeper investigation of these media was performed using conductivity, UV-Vis and FT-IR spectroscopy techniques. Different regimes of conductivity, depending on the water content, an increase of the polarity of the polar pseudo-phase with increasing water content, and even the presence of free water molecules at higher water content are observed, just as in classical surfactant-based microemulsions. The percolation model, generally used to fit conductivity data in surfactant based microemulsion having a weak interfacial film, can be used to fit our conductivity data below a critical water content Φ(p)(w) with a critical exponent typical of dynamic percolation. In presence of higher water contents, superior to Φ(p)(w), obtained conductivity data cannot be fitted neither with a static nor a dynamic percolation model. As in surfactant-based microemulsions, an increase of polarity of the microenvironment with increasing water content can be postulated using respectively the UV-Vis wavelength absorption band (λ(max)) of methyl orange and performing FT-IR spectra.
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Influence of high intensity sweeteners and sugar alcohols on a beverage microemulsion. J Colloid Interface Sci 2015; 460:105-12. [DOI: 10.1016/j.jcis.2015.08.036] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 08/19/2015] [Accepted: 08/20/2015] [Indexed: 11/25/2022]
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Consistent definitions of “the interface” in surfactant-free micellar aggregates. Colloids Surf A Physicochem Eng Asp 2015. [DOI: 10.1016/j.colsurfa.2014.11.029] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Toward surfactant-free and water-free microemulsions. J Colloid Interface Sci 2015; 453:186-193. [DOI: 10.1016/j.jcis.2015.04.069] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 04/29/2015] [Accepted: 04/30/2015] [Indexed: 11/26/2022]
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Weak Micelle-Like Aggregation in Ternary Liquid Mixtures as Revealed by Conductivity, Surface Tension, and Light Scattering. J Phys Chem B 2015; 119:9933-9. [DOI: 10.1021/acs.jpcb.5b06228] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Effects of salts and sucrose on the phase behavior of ternary mixtures of water, decane, and mono-ethylene glycol butyl ether. Colloids Surf A Physicochem Eng Asp 2015. [DOI: 10.1016/j.colsurfa.2015.03.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Influence of additives on the structure of surfactant-free microemulsions. Phys Chem Chem Phys 2015; 17:32528-38. [DOI: 10.1039/c5cp06364g] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In surfactant-free microemulsions, the combination ethanol/antagonistic salt behaves like a surfactant.
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Nano-droplet formation in water/ethanol or isopropanol/mosquito repellent formulations. Colloids Surf A Physicochem Eng Asp 2014. [DOI: 10.1016/j.colsurfa.2013.11.030] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Octanol-rich and water-rich domains in dynamic equilibrium in the pre-ouzo region of ternary systems containing a hydrotrope. J Appl Crystallogr 2013. [DOI: 10.1107/s002188981302606x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Ternary mixtures of medium-chain fatty alcohols, water and a hydrotrope (such as ethanol), near the immiscibility gap, make stable single phases at constant temperature. Interestingly, in this `pre-ouzo region' these single phases consist of two distinct nanoscopic pseudo-phases, one octanol-rich and one water-rich. This domain of composition, which is known to produce strong light scattering and to separate under ultracentrifugation into two phases, has been studied using contrast variation in small-angle neutron scattering (SANS) combined with small- and wide-angle X-ray scattering (SWAXS). The existence of fatty alcohol-rich domains of well defined size of the order of 2 nm radius is proven. The scattering can be approximated by an Ornstein–Zernike function, which is close to the general expression of Choi, Chen, Sottmann & Strey [Physica B, (1998),241–243, 976–978] with vanishing quadratic Porod term. Exploitation of the relative intensities at the vanishing scattering angle in SANS demonstrates that the distribution coefficient of ethanol between the octanol-rich and the water-rich domains is close to one. WAXS of the two coexisting pseudo-phases is compared with the corresponding binary water–ethanol and octanol–ethanol samples.
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Formulation and stability of a soap microemulsion and the apparent pKA herein. J Colloid Interface Sci 2013; 407:382-9. [DOI: 10.1016/j.jcis.2013.06.052] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2013] [Revised: 06/17/2013] [Accepted: 06/19/2013] [Indexed: 11/16/2022]
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Pharmacokinetics of a self-microemulsifying drug delivery system of tacrolimus. Biomed Pharmacother 2013; 67:469-73. [PMID: 23669280 DOI: 10.1016/j.biopha.2013.04.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 04/08/2013] [Indexed: 11/26/2022] Open
Abstract
This study evaluated the pharmacokinetics of tacrolimus (Tac) in a novel self-microemulsifying drug delivery system (SMEDDS) for improved oral administration. SMEDDS Tac consisted of ethyl oleate as the oily phase, Solutol HS 15 as the surfactant and glycofurol as the co-surfactant and contained 0.5mg/mL tacrolimus. Blood and tissue concentrations of tacrolimus from two study groups (oral application of SMEDDS Tac and Prograf®) were determined using ELISA technique following tacrolimus administration in rats. There was no difference between area under the whole blood concentration-time curve in the SEDDM Tac group and the Prograf® group. Maximum concentrations of the drug were three times higher (P<0.05) in the SEDDM Tac group accompanied by a 3-fold earlier peak time. Elimination half-life was significantly lower in the SEDDM Tac group. Application of SMEDDS Tac increased tissue accumulation. Already after 15 min, Tac levels of small intestine, liver, kidney, spleen, heart and bone marrow were significantly higher in the SMEDDS Tac group than in the Prograf® group (P<0.05). However, the Tac concentration in the kidney was significantly lower in the SMEDDS Tac group. Formulation of SMEDDS did not affect blood-brain barrier function. The SMEDDS is a potentially useful method for a local delivery of Tac to target organs. The selection of the optimum SMEDDS Tac composition might have advantage as an alternative oral dosage form for Tac.
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Biodegradability and cytotoxicity of choline soaps on human cell lines: effects of chain length and the cation. RSC Adv 2013. [DOI: 10.1039/c3ra42812e] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Eco-solvents – cluster-formation, surfactantless microemulsions and facilitated hydrotropy. Phys Chem Chem Phys 2013; 15:10971-7. [DOI: 10.1039/c3cp50636c] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Structure and Solubility in Surfactant-Free Microemulsions. Chemphyschem 2012; 13:4116-9. [DOI: 10.1002/cphc.201200667] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Indexed: 11/12/2022]
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Effect of salts on the phase behavior and the stability of nanoemulsions with rapeseed oil and an extended surfactant. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:8318-8328. [PMID: 22537241 DOI: 10.1021/la300435t] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
For many decades, the solubilization of long-chain triglycerides in water has been a challenge. A new class of amphiphiles has been created to overcome this solubilization problem. The so-called "extended" surfactants contain a hydrophilic-lipophilic linker to reduce the contrast between the surfactant-water and surfactant-oil interfaces. In the present contribution, the effects of different anions and cations on the phase behavior of a mixture containing an extended surfactant (X-AES), a hydrotrope (sodium xylene sulfonate, SXS), water, and rapeseed oil were determined as a function of temperature. Nanoemulsions were obtained and characterized by conductivity measurements, light scattering, and optical microscopy. All salting-out salts show a transition from a clear region (O/W nanoemulsion), to a lamellar liquid crystalline phase region, a clear phase (bicontinuous L(3)), and again to a lamellar liquid crystalline phase region with increasing temperature. For the phase diagrams with NaSCN and Na(2)SO(4), only one clear region (O/W nanoemulsion) was observed, which turns into a lamellar phase region at elevated temperatures. Furthermore, the stability of the nanoemulsions was investigated by time-dependent measurements: the visual observation of phase separation, droplet size by dynamic light scattering (DLS), and optical microscopy. The mechanism of the different phase transitions is also discussed.
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Green synthesis of para-Menthane-3,8-diol from Eucalyptus citriodora: Application for repellent products. CR CHIM 2011. [DOI: 10.1016/j.crci.2011.02.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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50
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Hydrotrope-induced inversion of salt effects on the cloud point of an extended surfactant. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:4403-11. [PMID: 21443178 DOI: 10.1021/la104744e] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We report on the effects of electrolytes spanning a range of anions (NaOc, NaSCN, NaNO(3), NaBr, NaCl, NaBu, NaOAc, Na(2)SO(4), Na(2)HPO(4), and Na(2)CO(3)) and cations (LiCl, NaCl, KCl, CsCl, and choline chloride) on the aqueous solubility of an extended surfactant. The surfactant is anionic with a long hydrophobic tail as well as a significant fraction of propylene oxide groups and ethylene oxide groups (C(12-14)-PO(16)-EO(2)-SO(4)Na, X-AES). In the absence of electrolytes, X-AES exhibits a cloud-point temperature that decreases with increasing surfactant concentration. After the addition of salts to the surfactant solutions, various shifts in the solubility curves are observed. These shifts follow precisely the same Hofmeister series that is found for salting-in and salting-out effects in protein solutions. In the presence of different concentrations of sodium xylene sulfonate (SXS), the solubility of the surfactant increases. In this context, SXS can be considered to be a salting-in salt. However, when the electrolytes are added to an aqueous solution of X-AES and SXS the Hofmeister series reverses for divalent anions such as Na(2)SO(4), Na(2)HPO(4), and Na(2)CO(3). Studies on the phase behavior and micelle structures using polarization microscopy, freeze-etch TEM, and NMR measurements indicate a dramatic change in the coexisting phases on the addition of SXS.
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