Effect Of Solvent Selectivity Research Articles

꾸지뽕나무 열매 추출물의 Chlorogenic Acid, Rutin 함량 분석 및 생리활성

This study was carried out to very precisely understand the effect of solvent selection on the molecular properties in the investigation of the biological activity according to the molecular size of chitosan. Chitosan hydrolysates derived from the hydrolysis of high molecular weight chitosan (HMWC) were prepared in enzymatic hydrolysis under solvent selective conditions. Chitosan hydrolysates were characterized by HPLC and Matrix-Assisted Laser Desorption/ Ionization-Time of Flight (MALDI-TOF) mass spectrometry analyses, respectively. HPLC analysis did not show a significant difference in the size of hydrolysates according to the type of chitosan. On the other hand, it was confirmed that each molecular size was significantly different from the results presented by HPLC with MALDI-TOF mass spectrometry analysis. In addition, the effect on the antibacterial activity of the hydrolysates of chitosan, designated to “active molecular chitosan (AMC)”, by the solvent selected for the enzymatic reaction also showed a significant difference. Therefore, it is intended to suggest that the selection of solvents for the enzymatic reaction for chitosan hydrolysis and their antibacterial activity is very important.

Biological Activity of Cannabis sativa L. Extracts Critically Depends on Solvent Polarity and Decarboxylation

Minor cannabinoid and non-cannabinoid molecules have been proposed to significantly contribute to the pharmacological profile of cannabis extracts. Phytoplant Research has developed highly productive cannabis cultivars with defined chemotypes, as well as proprietary methods for the extraction and purification of cannabinoids. Here, we investigate the effect of solvent selection and decarboxylation on the composition and pharmacological activity of cannabis extracts. A library of forty cannabis extracts was generated from ten different cannabis cultivars registered by Phytoplant Research at the EU Community Plant Variety Office. Plant material was extracted using two different solvents, ethanol and hexane, and crude extracts were subsequently decarboxylated or not. Cannabinoid content in the resulting extracts was quantified, and biological activity was screened in vitro at three molecular targets involved in hypoxia and inflammation (NF-κB, HIF-1α and STAT3). Changes in transcriptional activation were strongly associated to solvent selection and decarboxylation. Two decarboxylated extracts prepared with hexane were the most potent at inhibiting NF-κB transcription, while HIF-1α activation was preferentially inhibited by ethanolic extracts, and decarboxylated extracts were generally more potent at inhibiting STAT3 induction. Our results indicate that solvent selection and proper decarboxylation represent key aspects of the standardized production of cannabis extracts with reproducible pharmacological activity.

Effect of solvent selection and nozzle geometry on Curcuma mangga micronization process using supercritical antisolvent: Experiment and CFD simulation

In this study, ethanolic extracts of Curcuma mangga (C. mangga) were micronized using the supercritical antisolvent (SAS) method. Acetone, ethyl acetate, and dichloromethane were used as solvents to study the effects of solvent selection on the obtained particles. Supercritical carbon dioxide (CO2) was used as the antisolvent. The effects of nozzle geometry (cross nozzle and T-nozzle) on particle size and morphology were also evaluated. Microparticles and submicron particles were successfully produced with particle sizes ranging from 0.202 ± 0.05 μm to 1.653 ± 0.89 μm. Of the three solvents, ethyl acetate produced smaller particle sizes with a narrow particle size distribution. For all the types of solvents used, micronized particles prepared with the cross-nozzle had smaller average particle sizes than with the T-nozzle. The smallest particles of mean size 0.202 ± 0.05 μm were achieved at 16 MPa and 313 K using ethyl acetate as the solvent and a cross-nozzle. Computational fluid dynamics simulations were successfully performed on the internal flow to study the turbulent flow and volume fraction inside the nozzle. The results of this are expected to help improve the applications of the active ingredients of C. mangga rhizomes in the pharmaceutical industry.

Effect of Solvent Selectivity on Chain Exchange Kinetics in Block Copolymer Micelles

The effect of solvent selectivity on the chain exchange kinetics for two polystyrene-b-poly(ethylene-alt-propylene) block copolymer micelles (SEP 26–70 and SEP 42–64, where the numbers denote the m...

Amphiphilic Block Copolymer Micelles in Selective Solvents: The Effect of Solvent Selectivity on Micelle Formation.

We investigated the micellar behavior of a series of asymmetric polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) block copolymers in different P4VP-selective alcoholic solvents. The micellar behavior was further correlated with the spectroscopic ellipsometry results obtained on swelling of PS and P4VP polymer films in the corresponding solvent vapors. The time-resolved (in situ) dynamic light scattering (DLS) measurements, in combination with (ex situ) electron microscopy imaging, revealed information about the aggregation state of PS-b-P4VP BCP in different alcohols and the effect of heat treatment. The ellipsometry measurements allowed us to estimate the difference in solvent selectivity toward PS/P4VP pair. Both DLS and ellipsometric studies suggested that less polar alcohols (i.e., 1-propanol, 1-butanol, and 1-pentanol) are likely to be close to each other in terms of their selectivity toward PS/P4VP pair, whereas more polar ethanol and methanol show the highest and the lowest affinity toward P4VP, respectively.

Fragmentation of 1,2-Polybutadiene-block-Poly(ethylene oxide) Micelles in Imidazolium-Based Ionic Liquids

The effect of solvent selectivity on the fragmentation kinetics of spherical micelles formed by a 1,2-polybutadiene-block-poly(ethylene oxide) “BO” copolymer in five 1-alkyl-3-methylimidazolium bis...

Preparation, characterization, intrinsic dissolution studies and microbiological assessment of dapsone tosylate polymorphs

Purpose: To prepare dapsone tosylate salt (TD) and its two polymorphs (TD-I and TD-II), and study their intrinsic dissolution profiles and preliminary anti-mycobacterium activity. Methods: The synthesized product was studied with respect to the effect of solvent selection, reaction temperature and evaporation rate on the solid phase obtained. The polymorphs were characterized using powder x-ray diffraction (PXRD), proton nuclear magnetic resonance ( 1 H-NMR), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). UV/Vis spectroscopy was employed for quantification of the salt, while Wood apparatus was used for dissolution studies. Microdilution assay, using a 96-well equipment, was employed for the evaluation of anti-mycobacterial activity. Results: On analysis of the solids obtained from synthesis with PXRD, two different patterns were observed. One pattern belonged to TD-I, previously reported, and the other was a new polymorph TD-II. Solvent evaporation was important in the selective preparation of TD-I or TD-II. Analyses with DSC, TGA and 1 H-NMR revealed the absence of solvent in both solids and showed that TD-II was not a solvated salt. Spectral analysis with FT-IR demonstrated structural relationship between TD-I and TD-II. Intrinsic dissolution studies showed that both polymorphs dissolved faster than dapsone (DAP). Conclusion: It is possible to synthesize TD and select the polymorph prepared by means of modulated solvent evaporation rate. The rank order of the intrinsic dissolution rate constants was TD-II > TD-I > DAP. The tosylate salt enhanced inhibitory effect on M. fortuitum, when compared to DAP. Keywords: Dapsone tosylate, Polymorphism, Solid phase characteristics, Intrinsic dissolution, Antimycobacterium activity

Effect of solvent selection on drug loading and amorphisation in mesoporous silica particles

Increasing the dissolution rate of poorly water-soluble active pharmaceutical ingredients (APIs) is a key strategy used for improving their oral bioavailability. One of the formulation approaches is API loading to mesoporous carrier particles, which can increase the dissolution rate through the combination of improved powder wettability and dispersion, higher surface area, and API conversion from crystalline to the amorphous state. From the formulation process point of view, the maximum achievable drug loading is a crucial parameter, which depends on the loading method. Drug loading by sorption from a solution is a technologically attractive approach, since it involves familiar unit operations (mixing, filtration, drying). However, the success of the equilibrium sorption approach depends on the choice of the solvent. In this work we present an experimental study of loading efficiency to mesoporous silica particles, based on a set of 10 APIs combined with 6 different solvents at a range of concentrations. We show that due to the competitive nature of the adsorption process, the solvent with the highest API solubility is not necessarily the best candidate for maximising the API loading. Based on the investigated drug-solvent combinations, we show that the dielectric constant of the solvent is a good predictor of loading efficiency and can be used as a general guideline for solvent selection. On the other hand, we did not find any systematic correlation between commonly measured API properties such as logP and their loading efficiency.

Effect of solvent selectivity on supramolecular assemblies of block copolymer by solvent-vapor annealing

Nanoparticles with well-ordered structures have attracted great attention recently due to its potential application, including data storage media, microelectronics and sensors. Herein, we report a strategy of the periodic arrays of iron oxide nanoparticle with supramolecular thin films. The thin films of PS-b-P2VP/FAA supramolecules were solvent-vapor annealed with mixed solvent-vapor condition of toluene: ethanol: water = 9: 1: 0.06 in volumetric ratio. The supramolecular thin film exhibited the structural change of disorder – vertical cylinder – vertical lamellae – mixture (cylinder and lamellae) - cylindrical morphology triggered by the addition of small amount of water due to the change of the solvent selectivity with major block depending on time, leading to the periodic arrays of iron oxide nanoparticle. We expect that this result can provide key information to fabricate the self-assembled naostructure of block copolymers by using the solvent-vapor processing without complicated procedures.

Influence of solvent selection and extraction temperature on yield and composition of lipids extracted from spent coffee grounds

Spent coffee grounds (SCG) are a potentially sustainable source of C16-C18 triglycerides. This study investigates known solvent extraction technologies with a wide range of solvents for lipid extraction from SCGs, and determines the effect of solvent selection and process temperature on the extraction efficiency and composition of the obtained oil. A correlation between increasing solvent boiling point, and therefore process temperature, and improved oil extraction efficiency was observed in Soxhlet extractions with a wide range of solvents. Experiments at elevated temperatures (up to 200 °C) were performed through Accelerated Solvent Extraction (ASE) and temperature increase initially improved the oil extraction efficiency when non-polar solvents were used, before decreasing it at higher temperatures. Utilization of ethanol resulted in the highest oil extraction ratio by ASE (at 165 °C), suggesting that temperature increase is more beneficial to the extraction efficiency of polar solvents. In addition, analysis of the oils was carried out to evaluate the composition of the oils extracted from SCGs using different solvents and extraction parameters. The Nuclear Magnetic Resonance (NMR) results were in agreement with the values obtained from the titrimetric determination of the free fatty acid content (FFA) of the oils in terms of the comparative trends, and also tentatively suggest that some differences in the composition of the extracted oils might be related to the type of extraction solvent used.

Effect of solvent selectivity on crystallization-driven fibril growth kinetics of diblock copolymers

We performed dynamic Monte Carlo simulations of diblock copolymers to investigate how the selective solvents on two blocks can suppress the crystallization-driven fibril self-assembly growth in dilute solutions. We found that either a lower hydrophilicity of the surrounding amorphous block or a lower hydrophobicity of the core crystallizable block can effectively reduce the fibril growth rates. Their mechanisms are different: the former is the shielding effect and the latter is the thermodynamic effect. We discussed the potential correlation of our results to the recent progress of drug discovery for the Alzheimer's disease that elongates the fibril structure of amyloid proteins as a consequence of crystallization of hydrophobic segments under nano-confinement of those hydrophilic segments. Our observations shed light onto the physicochemical background for the basic therapy strategy of protein-misfolding diseases.

Structure of poly(styrene‐b‐ethylene‐alt‐propylene) diblock copolymer micelles in binary solvent mixtures

ABSTRACTThe effect of solvent selectivity on the micelle structure formed by a poly(styrene‐b‐ethylene‐alt‐propylene) diblock copolymer (PS‐PEP, MPS = 42,000 g/mol and MPEP = 62,000 g/mol) in solutions of squalane, a highly selective solvent for the PEP block, and 1‐phenyldodecane, a neutral solvent, is investigated using dynamic light scattering (DLS) and small‐angle X‐ray scattering (SAXS). The results reveal that addition of 1‐phenyldodecane systematically reduces solvent selectivity, leading to decreases in the critical micelle temperature (TCMT) and the average number of chains in a micelle (Nagg), and an increase in the solvent fraction in the core. However, the core blocks have essentially unperturbed dimensions (i.e., Rc ≈ 2 × ⟨Rg⟩o, where ⟨Rg⟩o is unperturbed radius of gyration of the core block), and therefore the micelle core radius (Rc) is nearly independent of solvent selectivity, which has not been anticipated by previous theoretical descriptions. These results demonstrate that under such conditions, excluded volume effects in the corona blocks play the dominant role in determining micelle structure. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 22–31

The effect of solvent selection in the gas chromatographic analysis of carbonyls in air samples after derivatization with pentafluorophenyl hydrazine

Carbonyl compounds are an important component of atmospheric chemistry with the potential to form secondary pollutants (in gaseous and/or particulate forms). For their analysis, derivatization by pentafluorophenyl hydrazine has been applied in gas chromatography (GC) or high performance liquid chromatography (HPLC). Because of the need for an appropriate solvent, we have evaluated the relative derivatization performance of five solvents (methanol, pentane, hexane, dichloromethane, and water) for GC analysis. Six light and common (C1–C5) aldehydes (i.e., formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, i-valeraldehyde, and valeraldehyde) out of a large member of carbonyl compounds were selected in this research. Anomalously large response was observed for the formaldehyde-hydrazone prepared in methanol and water, while that of acetaldehyde-hydrazone was reduced for pentane (by ~89%) relative to the others. If we exclude these biased cases, their response factors were in the order of: methanol>pentane>hexane>dichloromethane>water. This ordering was seen consistently in their relative recovery: methanol>pentane>dichloromethane≈hexane>water. The method detection limits (ng) of the aldehyde-hydrazone (as aldehyde mass) in each solvent were in the order: 1.0 (hexane)<1.2 (dichloromethane)<1.6 (methanol)<2.5 (pentane)<4.0 (water). As such, evidence suggests that solvent should be selected carefully to optimize the GC-based quantitation of aldehyde-pentafluorophenyl-hydrazones.

Transition between crystallization and microphase separation in PS-b-PEO thin film Influenced by solvent vapor selectivity

In this paper, the effect of solvent selectivity on the transition between crystallization and microphase separation of the semicrystalline diblock copolymer polystyrene-b-poly(ethylene oxide) (PS-b-PEO) thin films was investigated. Square-shaped crystals formed due to lower barrier of crystalline nucleation in both poor and good solvent vapor for PEO. However, in poor solvent (cyclohexane) vapor for PEO, crystalline structure changed to microphase separated structure in the square platelets due to the high mobility of PS blocks. Then breakout crystals dominated the morphology of the film. While, in good solvent (water) vapor for PEO, competition between nucleation and dissolution of crystallization caused the formation of imperfect crystals. Then imperfect crystals dissolved due to the high mobility of PEO blocks, and microphase separation dominated the morphology of the film. The gain of free volume of soluble block and the low swelling of crystalline block are keys for microphase separation and crystallization, respectively.

Role of Solvent Selectivity in the Equilibrium Surface Composition of Monolayers Formed from a Solution Containing Mixtures of Organic Thiols

We have developed a simple model to quantify the effect of solvent selectivity on the surface composition of two-component self-assembled monolayers formed from solutions containing mixtures of organic thiols. The coarse-grained molecular model incorporates the relevant intermolecular interactions in the solution and monolayer to yield an expression for the free energy of monolayer formation. Minimization of the free energy results in a simple and analytically tractable expression for the monolayer composition as a function of solvent selectivity (defined as the difference in the Flory-type interaction parameters of the two organic thiols in the solution) and the degree of incompatibility between the adsorbate molecules. A comparison of our theory to experiments on the formation of two-component self-assembled monolayers from solution indicates that the coarse-grained molecular model captures the trends in the experimental data quite well.

Effect of Solvent on Controllability in Extractive Distillation

There have been numerous books and papers dealing with the effect of solvent selection on the steady-state design of extractive distillation systems. Extractive distillation is widely used to separate homogeneous binary azeotropes by adding a higher-boiling solvent that attracts one of the components. These systems typically feature an extractive column and a solvent-recovery column. The two products are removed in the distillate streams from the two columns. The solvent is circulated from the base of the solvent recovery back to near the top of the extractive column. A recent paper by Kossack et al. (Chem. Eng. Res. Dev., in press) discusses in detail the steady-state economic design issues and presents several examples that use a variety of solvents for the separation of acetone and methanol. Some solvents drive the acetone overhead in the extractive column, while others drive the methanol overhead in the extractive column.This paper extends this work to compare the dynamic performance of the acetone/me...

Quantitative bioanalysis of quinine by atmospheric pressure-matrix assisted laser desorption/ionization mass spectrometry combined with dynamic drop-to-drop solvent microextraction

Dynamic drop-to-drop solvent microextraction (DDSME) combined with atmospheric pressure-matrix assisted laser desorption/ionization mass spectrometry (AP-MALDI/MS) has been successfully applied on the bioanalysis of quinine using micro liter volume (30 μL) of human urine and plasma samples. The method is based on the movement of aqueous phase (AP) in and out of the microsyringe, which increases the transfer and diffusion rate of the quinine drug from aqueous phase to organic phase (OP). The optimization parameters including the effect of solvent selection, number of samplings, sampling volume, volume of aqueous phase, volume of organic phase, addition of salt and pH were investigated for obtaining higher extraction efficiency of the analyte. The limits of detections (LODs) of quinine, using the dynamic DDSME/AP-MALDI/MS in urine and plasma samples were 0.18 and 0.24 μM, respectively. The superiority of dynamic DDSME over static DDSME and liquid–liquid extraction (LLE) was also demonstrated for the determination of quinine in aqueous solution. This method is promising in clinical application and pharmacokinetic studies, in which the availability of sample amount is extremely small.

Effect of solvents on closed-loop phase behavior of block copolymers

We studied the effect of solvent selectivity on the closed-loop phase behavior of a polystyrene- block-poly( n-pentyl methacrylate) copolymer. It was found that the lower disorder-to-order transition temperature (LDOT) and upper order-to-disorder transition temperature (UODT) consisting of the closed-loop were very sensitive to the selectivity of the solvent. With the addition of very small amounts of non-selective solvents such as di- n-octyl phthalate and dimethyl phthalate, the LDOT increased rapidly, whereas the UODT decreased dramatically; thus, the immiscibility loop was shrunk greatly. On the other hand, both the LDOT and UODT decreased with increasing amount of dodecanol, a highly selective solvent to poly( n-pentyl methacrylate) block. However, the decrease in the LDOT was greater than that of the UODT, leading to an increased immiscibility loop.

Synthesis, optical and morphological characterization of soluble main chain 1,3,4-oxadiazole copolyarylethers—potential candidates for solar cells applications as electron acceptors

New copoly(arylether)s containing substituted terphenyl, quinquephenyl, fluorene and anthracene moieties with aromatic 1,3,4-oxadiazole units were prepared and the resulting copolymers are soluble in common organic solvents. Investigation of their optical properties revealed that they emit blue and yellow light. Moreover, their photovoltaic response was studied in blends with poly(3-hexylthiophene) (P3HT) as the electron donor. Despite the low power conversion efficiencies it was shown that photo-induced electron transfer does take place and the performances are higher than a single layer P3HT device. In addition, an anthracene–fluorene–oxadiazole main chain copolymer (PAFOXD) was also examined in a single layer photovoltaic device and gave one of the highest reported open-circuit voltage ( V oc) values in the literature (0.89 V). Finally, a detailed morphological study of the blends and the PAFOXD surface using the atomic force microscopy (AFM) technique, revealed the effect of solvent selection to the preparation of thin films exhibiting the desired performance characteristics.

Chromatographic behaviour of diastereoisomers XII. Effects of alumina on separations of esters of maleic and fumaric acids

The thin-layer chromatographic separations on three different aluminas of twenty diastereoisomeric 1,2-disubstituted ethenes, ROOCCH CHCOOR, were studied with 24 mobile phases having strength, ε, in the range 0.210–0.250 and a wide variety of solvent selectivity effects. The relative retention of the diastereoisomers was always Z > E independently of the type of the alumina and the increase in the selectivity of the mobile phases and the effective volume of the group R as a result of an expected site chelation via the two ester groups in Z isomers only. A comparison shows that the separations of these diastereoisomers are similar with both alumina and silica using a given mobile phase. However, the overall separation obtained on any alumina is better than that found for silica.