A Development Strategy of Tailor-made Natural Deep Eutectic Solvents for the Enhanced Extraction of Hydroxynaphthoquinones from Alkanna tinctoria Roots

Natural hydroxynaphthoquinone enantiomers (HNQs) are well-described pharmaceutical and cosmeceutical agents especially present in the roots of Alkanna tinctoria (L.) Tausch, a species native to the Mediterranean region. In this work, eco-friendly natural deep eutectic solvents (NaDESs) were developed for the selective extraction of these compounds. An extensive screening was performed using more than sixty tailor-made NaDESs. The impact of the intrinsic physicochemical properties on the HNQs extraction efficiency as well as the specificity towards the different enantiomeric pairs was thoroughly investigated. As a result of a multivariate analysis and of the one factor-a-time solvent optimization, the eutectic mixture composed of levulinic acid and glucose (LeG) using a molar ratio of 5:1 (molHBA:molHBD) and 20% of water (w/w) was found as the most appropriate mixture for the highest extraction efficiency of HNQs. Further optimization of the extraction process was attained by response surface methodology, using a temperature of 45 °C, a solid-to-liquid ratio of 30 mg/mL, and an extraction time of 50 min. A maximum extraction output of 41.72 ± 1.04 mg/g was reached for HNQs, comparable to that of the commonly used organic solvents. A solid-phase extraction step was also proposed for the recovery of HNQs and for NaDESs recycling. Our results revealed NaDESs as a highly customizable class of green solvents with remarkable capabilities for the extraction of HNQs.

DEEP EUTECTIC SOLVENTS AS AN ADDITIVE IN MODIFICATION OF MEMBRANEFOR NANO- AND ULTRA- FILTRATION: PHYSIC-CHEMISTRY CHARACTERISTICS, FTIR STUDY AND ELECTROCHEMICAL BEHAVIOR

Deep eutectic solvents (DESs) are a new class of solvents that can offset some of the primary drawbacks of typical solvents and ionic liquids. They are synthesized by simply mixing the components that interact with each other through hydrogen bonds, and form a eutectic mixture with a melting point much lower than each component individually. Deep eutectic solvents is usually liquid at temperatures below 100 °C. Thanks to these great advantages, deep eutectic solvents is attracting more and more attention in many areas of research. Very recently, great attention has been paid to new pioneering attempts aiming at deep eutectic solvents into the field of chemical engineering, including membrane science and technology. Even if just a same works have been currently reported in applying deep eutectic solvents in membranes, the consideration on this new type of solvents is continuously growing. New deep eutectic solvents based on choline chloride (ChCl)–lactic acid (1:2 M ratio) was obtained and its electrochemical characteristics was studied. The synthesis of deep eutectic solvents was confirmed by FA nuclear magnetic resonance (NMR) spectrometry method. FTIR study provided further details into hydrogen bonding upon mixing. FTIR results confirmed that H-bonds, occurring between two components in deep eutectic solvents, were the main force leading to the eutectic formation. The frequency at 3221 cm−1 can be attributed to the oscillations of the O-H bond in the formation of OH-Cl-ChCl. The main physicochemical characteristics of deep eutectic solutions (density, pH) are determined. The electrochemical behavior was investigated of choline chloride (ChCl)–lactic acid deep eutectic solvent (DES) by cyclic voltammetry. The method of cyclic voltammetry found that the oxidation of deep eutectic solvents is fixed at a potential of Ea1 = 0.54 V.

EXTRACTION OF FLAVONOIDS FROM KOENIGIA WEYRICHII USING DEEP EUTECTIC MIXTURE OF CHOLINE CHLORIDE + GLYCERINE

Koenigia Weyrichii (F. Schmidt) T.M. Schust. et Reveal, which grows on the Kola Peninsula, contains a significant amount of flavonoids in the aerial parts of the plant, rapidly builds up biomass, and is resistant to various climatic conditions. This makes K. Weyrichii a promising source of biologically active substances (BAS) in the Arctic zone. A relatively new method for extracting biologically active substances from plants is the use of deep eutectic solvents (DES), for example, a mixture of choline chloride with glycerol, which has shown high efficiency in the extraction of flavonoids from other plants. Previously, DES was not used for the extraction of biologically active substances from K. Weyrichii. The aim of this work is to evaluate the efficiency of ultrasonic extraction using traditional solvents (water, ethanol) and DES choline chloride + glycerol and to optimize the extraction conditions. Comparison of the total content of polyphenols, flavonoids, antioxidative, and antiradical activity in various extracts is carried out. It was found that the most favorable conditions for extraction are: water content in DES – 17.5 wt%, temperature – 65 °C, and time – 3 hours. At the same time, under identical extraction conditions (temperature and time), more target substances can be extracted with 60% ethanol than with DES. However, DES can be seen as an alternative to using ethanol. The data obtained can be useful for the further development of innovative technologies of the extraction of biologically active substances from plant material. Also, K. Weyrichii may be considered as a source of biologically active substances in cosmetics and the food industry.

Eutectic Formation of Naproxen with Some Dicarboxylic Acids

Eutectic formation with additives is one of the established methods to improve the dissolution behaviors of active pharmaceutic ingredients (APIs). The improvement is mainly due to the increase in the surface area for dissolution, which originates from the finely divided micro-domains generated through the phase separation of the miscible liquid components upon solidification. The present study is to identify eutectic-forming additives for naproxen (NPX), a class II API of the biopharmaceutical classification system. A particular aim was to develop a eutectic mixture with NPX at least over 20 wt%, a minimum to be practical for oral delivery. Screening based on the proximity of the solubility parameter values identified dicarboxylic acids (succinic acid, glutaric acid, and suberic acid) as desirable additives for NPX. Binary melting diagrams were constructed to confirm the eutectic compositions, and the eutectic mixture with suberic acid (NPX 55 wt%) was further investigated. The dissolution (at pH 5.0) of the melt crystallized eutectics was enhanced compared to the simple physical mixture of the same compositions and neat NPX, which was attributed to the microscopically observed lamellar structures. The current study should support the systematic investigations of API eutectic mixtures by selecting appropriate eutectic-forming additives.

Production of corundum armored ceramics

The purpose of this study was to develop the compositions and technology of corundum armored ceramics with high ballistic characteristics based on aluminum oxide with an α-Al2O3 content of more than 99 wt.%. The results of the study of the physicochemical processes of obtaining corundum ceramics modified with complex additives consisting of magnesium - aluminosilicate eutectic mixture and oxides of magnesium, yttrium, titanium, zirconium are presented. The introduction of complex additives into the composition of corundum ceramics provides a significant reduction (100-150°C) of the sintering temperature of the product. In this case, additives of yttrium and zirconium oxides contribute to the formation of a uniform-grained microstructure of ceramics, and in the case of adding titanium oxide, a collective recrystallization of corundum grains is noted. The use of small additives (0.3-0.5 wt.%) of magnesium and yttrium oxides together with a eutectic mixture in the compositions of corundum ceramics based on high-quality alumina contributes to the formation of a uniform-grained, dense structure of the material and giving it a high level of physical and mechanical properties as a result of directional the action of each component of the additive on the physicochemical processes of phase formation of the crystalline matrix. A model idea of the mechanism of action of additives on the formation of the microstructure of ceramics during stage-by-stage heating from 1350 to 1650°C in the sintering mode of products is presented. The developed compositions and technologies of corundum armored ceramics have a production focus and implementation in practice.

Electrodeposition of Nanostructured Chromium Conglomerates from Cr(III) Dissolved in a Deep Eutectic Solvent: Influence of Forced Convection

Cr electrodeposition onto glassy carbon rotating disk electrode (GCRDE) was studied from Cr(III) dissolved in the choline chloride and ethylene glycol eutectic mixture (ethaline) under different GCRDE angular speeds, ω, at 343 K. The ethaline kinematic viscosity, ν= 0.17〖 cm〗^2 s^(-1), was estimated, for the first time, from potentiodynamic plots. Analisys of potentiostatic current density transients, j-t plots, recorded at different ω, was based on the Hyde et al. (J. Electroanal. Chem. 534 (2002) 13) model, jdc-fcon(t), complemented by a previous adsorption step, jad(t), and the residual water reduction, jWR(t), taking place on the growing surfaces of the Cr nuclei. Nucleation frequency and number density of active sites showed small dependence on ω; however, jWR(t) clearly depends on it. SEM, EDS and XPS techniques were used to characterize the Cr electrodeposited. Electrodeposits were formed by quasi-spherical conglomerates (ca. 50 and 200 nm diameter for 0 and 1500 rpm, respectively) of nanoparticles (sized less than 30 nm diameter, in both cases). Moreover, these electrodeposits were formed by chromium and oxygen and its content increases with ω. These nanoparticles exhibit a core-shell structure: Cr(0)@ Cr(OH)3@ Cr2O3 which is consistent with the theoretical mechanism used for the analysis of the j-t plots

A Pilot Study on the Addition of Tramadol or Eutectic Mixture of Local Anesthetics (Prilocaine Plus Lignocaine) to Local Lignocaine Infiltration for Prevention of Bone Marrow Aspiration/Biopsy Associated Pain

Objectives Bone marrow aspiration although being a common procedure is associated with significant pain and its reduction remains an unmet need. We evaluated the use of tramadol and eutectic mixture of local anesthetics (prilocaine plus lignocaine) (EMLA) for reducing the severity of pain. Materials and Methods In this pilot study, we compared the addition of either tramadol 50 mg per oral (T) or EMLA local application (E) or no intervention (L) in addition to the usual procedure of local infiltration with lignocaine 2% before bone marrow aspiration and biopsy (BMAB) in adults suspected/confirmed with malignancy. Both, tramadol and EMLA were administered 1 hour prior to the procedure. Primary end point was reduction in pain intensity with these interventions compared with local infiltration alone. Pain was assessed using numerical FACES pain scale, a visual analogue scale. Secondary end points were to see the effect on pre procedure apprehension and to find out the other factors associated with increased pain related to the procedure. Statistical Analysis and Results A total of 300 patients were included in the study, 100 each in tramadol (T), EMLA (E), and only lignocaine local infiltration (L) arms, respectively. The mean pain intensity on the visual scale was significantly lower in the tramadol arm (T, E, L—3.4, 4.4, 4.7, respectively) (p < 0.0005). There was a significant reduction in percentage of patients who experienced moderate/severe pain (four or more) in the tramadol arm (T, E, L—45, 77, 82%, respectively) (p < 0.0005). Duration of procedure >10 minutes, body mass index >30, ECOG (Eastern Oncology Group) performance status ≥3, and age >50 years were positively correlated with more pain. Leukemia patients experienced significantly more pain compared with patients with lymphoma and other solid malignancies. Tramadol was well tolerated. No significant effect on pre-procedure apprehension was noted in any of the arms. Conclusion Tramadol appears to have a preventive effect on bone marrow aspiration/biopsy-associated pain and appears to be well tolerated, whereas EMLA was not associated with such an effect. Larger studies may be done to ascertain the same.