Effects of compositions on the stability of polyols-in-oil-in-water (P/O/W) multiple emulsions

Polyols-in-oil-in-water (P/O/W) multiple emulsions were successfully prepared by using polyols as inner aqueous phase to avoid instabilities caused by water. The influence of polyols, oils and emulsifiers on the morphology and stability of P/O/W multiple emulsions were studied and the stability mechanisms of this new kind of multiple emulsions were also explored. Glycerol that has the worst solubility in oil phase contributed to the formation of stable inner droplets which agree with the Ostwald Ripening theory. Mineral oil worked well with the system proving that oils possessing similar solubility parameters with the hydrophobic group of emulsifiers benefited for system stability. Several typical surfactants had been investigated in this article, and it turned out that emulsifiers Cetyl PEG/PPG-10/1 Dimethicone and the block copolymer Poloxamer 407 were suitable for the P/O/W system. The stability of the system affected by different compositions was evaluated based on microscopic observation and rheological measurements. The novel multiple emulsions will provide enlightening recommendations for future investigations and applications in cosmetic, food and pharmaceuticals, including drug delivery and the encapsulation of hydrophilic actives and actives that are soluble in polyols.     

Photodegradation of Caffeic Acid in W/O/W Emulsions in the Absence and in the Presence of TiO2

Caffeic acid, a natural phenol with antioxidant and sunscreen activity, can undergo photooxidation upon UV irradiation. The photodegradation of caffeic acid at different concentrations was assessed in water, at pH 4.0 and 6.0, without and with TiO₂. The study was then carried out on W/O/W emulsions entrapping the phenolic acid either in the inner or in the outer aqueous phase in the absence and in the presence of TiO₂, added in the external phase (pH 6.0 or 7.0). The degradation of caffeic acid followed a pseudo-zero order kinetic with an inverse dependence from its initial concentration; at increasing pH of the medium caffeic acid degraded faster. The addition of TiO₂ increased the initial photodegradation rate. Compared with water, W/O/W emulsions protected the phenol towards both the photodegradation and the photocatalytic activity of TiO₂. Multiple systems allowed to incorporate caffeic acid and TiO₂ in the same formulation avoiding any catalytic interactions.     

Preparation of a stable double emulsion (W1/O/W2): role of the interfacial films on the stability of the system

This paper presents new protocols enabling preparation of W1/O/W2 double emulsions: one, using soybean oil as the O phase, that yields edible emulsions with industrial applications, and a second that yields emulsions with a previously unattainable concentration 15% (w/w) of surfactants in the external phase (the 15% target was chosen to meet the typical industry standard). Preparation of a stable W1/O emulsion was found to be critical for the stability of the system as a whole. Of the various low HLB primary surfactants tested, only cethyl dimethicone copolyol (Abil EM90), A-B-A block copolymer (Arlacel P135), and polyglycerol ester of ricinoleic acid (Grinstead PGR-90) yielded a stable W/O emulsion. Investigation of the surface properties of those surfactants using the monolayer technique found two significant similarities: (1) stable, compressible, and reversibly expandable monolayers; and (2) high elasticity and surface potential. The high degree of elasticity of the interfacial film between W1 and O makes it highly resilient under stress; its failure to break contributes to the stability of the emulsion. The high surface potential values observed suggest that the surfactant molecules lie flat at the O/W interfaces. In particular, in the case of PGR-90, the hydroxyl (-OH) groups on the fatty acid chains serve as anchors at the O/W interfaces and are responsible for the high surface potential. The long-term stability of the double emulsion requires a balance between the Laplace and osmotic pressures (between W1 droplets in O and between W1 droplets and the external aqueous phase W2). The presence of a thickener in the outer phase is necessary in order to reach a viscosity ratio (preferably approximately 1) between the W1/O and W2 phases, allowing dispersion of the viscous primary emulsion into the W2 aqueous phase. The thickener, which also serves as a dispersant and consequently prevents phase separation due to its thixotropic properties, must be compatible with the surfactants. Finally, the interactions between the low and high HLB emulsifiers at the O/W2 interface should not destabilize the films. It was observed that such destructive interaction for the system could be prevented by the use of two high HLB surfactants in the outer aqueous phase: an amphoteric surfactant, Betaine, and an anionic surfactant, sodium lauryl ether sulfate. The combination of such pairs of surfactants was found to contribute to the films' stability.     

Natural Brazilian Raw Material to Develop O/W Emulsions Containing Lamellar Gel Phase (Development and Analysis of Emulsion with Vegetable Oils)

Oil-in-water emulsions were developed employing the HLB system and emulsion phase inversion (EPI) method. X-ray diffraction revealed that the anisotropic structures around the inner phase globules were lamellar gel network phases. The calculated distances between the lamellae made after preparation and 3 month latter showed that there was no swelling of the lamellar gel network indicating good stability and few changes during storage. The developed emulsions were stable and have potential to be employed for cosmetic and pharmaceutical purposes. The gel phase network and vegetal components seemed to be contributing factors.      

微乳液的增敏作用研究—5－Br－PADAP分光光度测定锰（Ⅱ）

以含水量８０％的Ｏ／Ｗ型ＳＤＳ／正丁醇／正庚烷／水微乳液为介质，以５－Ｂｒ－ＰＡＤＡＰ为显色剂，分光光度测定Ｍｎ（Ⅱ）．表观摩尔吸光系数ε５７０＝１．０８×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，与相同含水量的ＳＤＳ胶束体系相比，测定灵敏度有显著提高，改善了实验条件．方法用于铝合金和茶叶中Ｍｎ（Ⅱ）的测定，结果令人满意     

In Silico Approach for the Evaluation of the Potential Antiviral Activity of Extra Virgin Olive Oil (EVOO) Bioactive Constituents Oleuropein and Oleocanthal on Spike Therapeutic Drug Target of SARS-CoV-2

Since there is an urgent need for novel treatments to combat the current coronavirus disease 2019 (COVID-19) pandemic, in silico molecular docking studies were implemented as an attempt to explore the ability of selected bioactive constituents of extra virgin olive oil (EVOO) to act as potent SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) antiviral compounds, aiming to explore their ability to interact with SARS-CoV-2 Spike key therapeutic target protein. Our results suggest that EVOO constituents display substantial capacity for binding and interfering with Spike (S) protein, both wild-type and mutant, via the receptor-binding domain (RBD) of Spike, or other binding targets such as angiotensin-converting enzyme 2 (ACE2) or the RBD-ACE2 protein complex, inhibiting the interaction of the virus with host cells. This in silico study provides useful insights for the understanding of the mechanism of action of the studied compounds at a molecular level. From the present study, it could be suggested that the studied active phytochemicals could potentially inhibit the Spike protein, contributing thus to the understanding of the role that they can play in future drug designing and the development of anti-COVID-19 therapeutics.     

Concerning the Reaction of the Betain‐Like Compound O2CC(PPh3)2 with Tungsten‐Carbonyl Derivatives; Preparation and Crystal Structures of [(CO)5W{η1‐O2C2(PPh3)2}] and [(CO)4W{η2‐O2C2(PPh3)2}]

The carbodiphosphorane CO₂ adduct O₂CC(PPh₃)₂ ( 1a ) reacts with [(CO)₅W(THF)] and [(CO)₃W(NCEt)₃] to produce the complexes [(CO)₅W{η¹‐O₂CC(PPh₃)₂}] ( 2 ) and [(CO)₄W{η²‐O₂CC(PPh₃)₂}] ( 3 ), respectively. Whereas in 2 the betain‐like ligand is coordinated at the tungsten atom in a monodentate manner, in 3 it acts as a chelating ligand with formation of a WO₂C four‐membered ring. As a by‐product during the reaction with the acetonitrile adduct also some crystals of the hydrolysis product [HC(PPh₃)₂]₂[W₆O₁₉] · 3C₂H₄Cl₂ (4 · 3C₂H₄Cl₂) were isolated. All compounds could be characterized by X‐ray analyses and the usual spectroscopic methods.     

Reactivity of bis(pyrazol-1-yl)methanes functionalized by 2-hydroxyphenyl and 2-methoxyphenyl on the methine carbon atom with W(CO)5THF

Reactions of 2-hydroxyphenyl and 2-methoxyphenylbis(pyrazol-1-yl)methanes as well as 2-hydroxyphenyl and 2-methoxyphenylbis(3,5-dimethylpyrazol-1-yl)methanes with W(CO)₅THF have been carried out. Heating 2-hydroxyphenylbis(pyrazol-1-yl)methane (L¹) with W(CO)₅THF in THF at reflux yielded complex (L¹)W(CO)₄.L¹, while similar reaction of 2-hydroxyphenylbis(3,5-dimethylpyrazol-1-yl)methane (L²) with W(CO)₅THF resulted in the cleavage of a C_sp3-N bond to generate 1,2-bis(2-hydroxyphenyl)-1,2-bis(3,5-dimethylpyrazol-1-yl)ethane (L) and pyrazole derivative W(CO)₅(3,5-Me₂PzH) (Pz = pyrazol-1-yl). These two fragments were connected together through strong O…H-N and O-H…N hydrogen bonds to form complex L.[W(CO)₅(3,5-Me₂PzH)]₂. The analogous results were observed in the treatment of 2-methoxyphenylbis(pyrazol-1-yl)methane (L³) with W(CO)₅THF, which gave product L′.[W(CO)₅(PzH)]₂ (L′ = 1,2-bis(2-methoxyphenyl)-1,2-bis(pyrazol-1-yl)ethane) as well as certain amount of complex (L³)W(CO)₄. In addition, during the reaction of 2-methoxyphenylbis(3,5-dimethylpyrazol-1-yl)methane (L⁴) with W(CO)₅THF, partial decomposition reactions took place to yield complexes (L⁴)W(CO)₄ and W(CO)₅(3,5-Me₂PzH), but no hydrogen bond was found between these two moieties.     

KF/Al203催化下由芳醛、丙二腈和2-(1,2-二氢-3-亚茚基)丙二腈或2-(2,3-二氢-4H-亚萘基)丙二腈-步合成芴或菲衍生物

以芳醛、丙二腈、2-(1,2-二氢-3-亚茚基)丙二腈或2-(2,3-二氢-4H-亚萘基)丙二腈为原料,乙醇为溶剂,在80℃下以KF/Al2O3为催化剂合成了一系列芴或菲的衍生物,该方法具有反应条件温和,产率高(72%～88%)和操作简单等优点.产物的结构通过IR,1H NMR和元素分析表征.     

KF/Al2O3催化下由芳醛、丙二腈和2-(1,2-二氢-3-亚茚基)丙二腈或2-(2,3-二氢-4H-亚萘基)丙二腈一步合成芴或菲衍生物

以芳醛、丙二腈、2-(1,2-二氢-3-亚茚基)丙二腈或2-(2,3-二氢-4H-亚萘基)丙二腈为原料, 乙醇为溶剂, 在80 ℃下以KF/Al2O3为催化剂合成了一系列芴或菲的衍生物, 该方法具有反应条件温和、产率高(72%～88%)和操作简单等优点. 产物的结构通过IR, 1H NMR和元素分析表征.     

Theoretical study on the substitution and insertion reactions of silylenoid H2SiLiF with CH3XHn−1 (X = F, Cl, Br, O, N; n = 1, 1, 1, 2, 3)

The substitution and insertion reactions of H₂SiLiF (A) with CH₃XH_n−1 (X = F, Cl, Br, O, N; n = 1, 1, 1, 2, 3) have been studied using density functional theory. The results indicate that the substitution reactions of A with CH₃XH_n−1 proceed via two reaction paths, I and II, forming the same product H₂SiFCH₃. The insertion reactions of A with CH₃XH_n−1 form H₂SiXH_n−1CH₃. The following conclusions emerge from this work. (i) The substitution reactions of A with CH₃XH_n−1 occur in a concerted manner. The substitution barriers of A with CH₃XH_n−1 for both pathways decrease with the increase of the atomic number of the element X for the same family systems or for the same row systems. Path I is more favorable than path II. (ii) A inserts into a C-X bond via a concerted manner, and the reaction barriers increase for the same-row element X from right to left in the periodic table, whereas change very little for the systems of the same-family element X. (iii) The substitution reactions occur more readily than the insertion reactions for A with CH₃XH_n−1 systems. (iv) All substitution and insertion reactions of A with CH₃XH_n−1 are exothermic. (v) In solvents, the substitution reaction process of A with CH₃XH_n−1 is similar to that in vacuum. The barrier heights in solvents increase in the order CH₃F < CH₃Cl < CH₃Br < CH₃OH < CH₃NH₂. The solvent polarity has little effects on the substitution barriers. The calculations are in agreement with experiments.     

A Cheap and Efficient Methodology for the Solvent‐Free,One‐pot and Multi‐component Synthesis of 3,4‐Dihydropyrimidin‐2(1H)‐ones Catalyzed by Mesoporous NH4H2PO4/MCM‐48 and Comparison of Its Catalytic Efficacy with NH4H2PO4/MCM‐41

The catalytic efficiency of ammonium dihydrogenphosphate was evaluated in the two heterogeneous forms of NH₄H₂PO₄/MCM‐48 and NH₄H₂PO₄/MCM‐41, as mesoporous catalysts, in the solvent free synthesis of 3,4‐dihydropyrimidin‐2(1H)‐ones through one‐pot three‐component condensation of ethyl acetoacetate, an aryl aldehyde and urea. Different reaction parameters including catalytic efficacy, solvent effect, and urea concentration are considered.