Physical Solvent Research Articles

Solubility and Dissolution Improvement of Paramethoxycinnamic Acid (PMCA) Induced by Cocrystal Formation using Caffeine as a Coformer

Para-methoxy cinnamic acid (pMCA) is a derivative compound of ethyl p-methoxycinnamate that could be obtained in nature. pMCA has excellent pharmacological properties. However, in their application as a drug, pMCA has poor water solubility. In this present research, we try to increase the water solubility of pMCA using the cocrystal formation (cocrystallization) strategy. Here, we use caffeine as a coformer that can interact very well with pMCA via non-covalent bonding and Van der Waals interaction to achieve cocrystal formation. The cocrystal samples were successfully synthesized using various synthesis techniques; physical mixture, solvent evaporation, and microwave radiation methods. It shows that the solubility of the samples synthesized using microwave-assisted and solvent evaporation increases about 3.30 and 3.12 times, respectively, whereas the dissolution rate profile increases 2.50 and 2.39 times, respectively, compared to pure APMS. Our findings explain the importance of the cocrystal formation strategy to enhance the solubility of active material pMCA. This strategy can also be used as a standard formulation of a new drug system with excellent solubility and dissolution which is very important for the pharmaceutical industry.

Ethyl levulinate regulates traditional sulfolane biphasic absorbent for energy-efficient CO2 capture

Traditional CO2 biphasic absorbents currently suffer from problems such as high initial phase separation loading, poor product distribution selectivity, and weak dynamic phase separation ability, which limit their potential for industrial applications. This study developed a biphasic absorbent regulated by dual physical solvents by introducing partial ethyl levulinate (EL) into a sulfolane biphasic system. The optimal composition of this system was 30 wt% 1-amino-2-propanol (MIPA), 20 wt% sulfolane and 30 wt% EL. Under dual physical solvent conditions, strong electrostatic attraction between MIPA and CO2 promoted generation of MIPA zwitterions and carbamate. Analysis of the interactions between different product components through electrostatic potentials and with an independent gradient model based on Hirshfeld's partitioning revealed only extremely weak van der Waals force-driven interactions between the reaction products and EL. These interactions substantially reduced the initial phase separation loading and offered precise control over phase transition behavior. Compared with MIPA/sulfolane system, the MIPA/sulfolane/EL system achieved a 48.9 % lower initial phase separation loading, an 11.6 % lower proportion of saturated rich phase volume, a 10.1 % higher CO2-rich phase loading, and a 6.7 % lower viscosity. The excellent dynamic phase separation performance was verified using a customized device and the energy consumption for CO2 regeneration decreased to 2.2 GJ/t CO2.

Efficient photocatalytic H2 evolution over CuCo2S4 decorated ZnIn2S4 with S-scheme charge separation way

The construction of an S-scheme heterojunction can facilitate the separation and utilization of photogenerated charges, as well as reserve the reducing power of electrons to induce proton reduction for H2 evolution. In this study, CuCo2S4 nanoparticles and ZnIn2S4 nanoflowers were both synthesized via a hydrothermal method, and then CuCo2S4 was employed to decorate ZnIn2S4 to form CuCo2S4/ZnIn2S4 heterojunction through a simple physical solvent evaporation strategy. The experiment result shows that the rate of photocatalytic H2 evolution (rH2) over 10 wt% CuCo2S4/ZnIn2S4 can reach up to 20421.3 μmol g−1 h−1, which is 4.0 times that of ZnIn2S4 (5062.5 μmol g−1 h−1) and 144.6 times that of CuCo2S4 (141.2 μmol g−1 h−1). The improved activity results from the establishment of an S-scheme charge transfer way between CuCo2S4 and ZnIn2S4, which facilitates efficient charge separation while preserving active e− and h+. Besides, the formation of the heterojunction broadens the range of light absorption, promotes charge carrier generation, reduces charge transfer impedance, and increases electrochemically active surface area, these together lead to faster H2 evolution kinetics. The present study demonstrates the potential of bimetallic sulfides as a promising catalyst for construction ZnIn2S4-based photocatalysts for efficient solar conversion.

Selectivities of Carbon Dioxide over Ethane in Three Methylimidazolium-Based Ionic Liquids: Experimental Data and Modeling.

This work focused on the solubility of ethane in three promising ionic liquids {1-Hexyl-3-methylimidazolium bis(trifluormethylsulfonyl) imide [HMIM][Tf2N], 1-Butyl-3-methyl-imidazolium dimethyl-phosphate [BMIM][DMP], and 1-Propyl-3-methylimidazolium bis(trifluoromethyl-sulfonyl)-imide [PMIM][Tf2N]}. The solubilities were measured at 303.15 K to 343.15 K and pressures up to 1.4 MPa using a gravimetric microbalance. The overall ranking of ethane solubility in the ionic liquids from highest to lowest is the following: [HMIM][Tf2N] > [PMIM][Tf2N] > [BMIM][DMP]. The Peng-Robinson equation of state was used to model the experimental data using three different mixing rules: van der Waals one, van der Waals two, and Wong-Sandler mixing rules combined with the Non-Random Two-Liquid model. The average absolute deviations for the three mixing rules for the ionic liquids at the three temperatures were 4.39, 2.45, and 2.45%, respectively. Henry's Law constants for ethane in [BMIM] [DMP] were the highest (lowest solubility) amongst other ionic liquids studied in this work. The solubility ranking for the 3 ILs was confirmed by calculating their overall polarity parameter (N) using COSMO-RS. The selectivity of CO2 over C2H6 was estimated at three temperatures, and the overall ranking of the selectivity was in the following order: [PMIM][Tf2N] > [BMIM][DMP] > [HMIM][Tf2N] > Selexol. Selexol is an efficient and widely used physical solvent in gas sweetening. It has lower selectivity than the three ionic liquids studied. [PMIM][Tf2N], a promising solvent, has the highest selectivity among the three ILs studied and would, therefore, be the best choice if, in addition to carbon dioxide capture, ethane co-absorption was to be avoided. The enthalpy and entropy of solvation at infinite dilution were also estimated.

Tuning Stopper Size in Multiresponsive [2]Rotaxanes for Fluoride Anion Selective Metastability.

[23]Crown-7-ether incorporated [2]rotaxanes, comprising an anthracene blocker and 4-isopropylphenyl/cyclohexyl end groups, exhibited varying degrees of metastability with a range of chemical (base, halide anions) and physical (solvent, heat) stimuli. Among halides, fluoride, chloride, and bromide anions affected the deslippage of 23-crown-7-ether in 4-isopropylphenyl stoppered [2]rotaxane. Surprisingly, only fluoride anions could selectively induce deslippage in cyclohexyl stoppered [2]rotaxane, whose fluorescence quenching provided an additional tool to selectively detect the fluoride anions down to 2.49 × 10-7 M.

Facile fabrication of S-scheme MnCo2S4/ZnIn2S4 heterojunction for photocatalytic H2 evolution

In this work, MnCo2S4 nano-particle and ZnIn2S4 nano-flower were synthesized via a facile hydrothermal method, respectively. The MnCo2S4/ZnIn2S4 heterojunction was subsequently fabricated using a physical solvent evaporation method. The photocatalytic H2 production rate over 10 wt. % MnCo2S4/ZnIn2S4 can reach 17.5 mmol·g−1·h−1 under the irradiation of a 300 W Xe lamp, with 20 % triethanolamine (TEOA) used as a sacrificial agent, which is 3.4 times and 54.6 times that of pure ZnIn2S4 (5.2 mmol·g−1·h−1) and MnCo2S4 (0.3 mmol·g−1·h−1). The improved performance can be attributed to the establishment of an S-scheme charge transfer pathway between MnCo2S4 and ZnIn2S4, which not only enhances charge separation but also preserves active electrons and holes. The formed heterojunction facilitates the broadening of the light absorption spectrum, enhance carriers generation, reduce charge transfer impedance, increase electrochemical activity surface area, and lower H2 evolution overpotential compared to individual components. The work offers a promising way for the development of stable and efficient sulfide heterojunction achieve efficent photocatalytic H2 evolution.

Biopolymers and their Nanocomposites: Current Status and Future Prospects

Abstract: For many years, petroleum-based polymers have been successfully enhanced by the addition of nanoparticles as additives. Carbon nanotubes, graphene, nanoclays, 2-D layered materials, and cellulose nano whiskers are a few of the several nanoreinforcements that are currently being researched. In comparison to unmodified polymer resin, the use of these nanofillers with bio-based polymers could improve a wide range of physical properties, including barrier, flame resistance, thermal stability, solvent uptake, and rate of biodegradability. This nano-reinforcement is a very appealing method to create new functional biomaterials for a variety of applications because these enhancements are typically achieved at minimal filler content.

Synthesis of Phosphorus/Arsenic Tridentate Ligands and Their Application for Luminescent Copper (I) Halide Complexes

AbstractWe synthesized arsenic analogs of a tridentate PPP ligand, bis[2‐(diphenylphosphino) phenyl] phenylphosphine, achieving yields of 40 % to 71 %. Additionally, we prepared copper (I) halide (CuX, X=Br, I) complexes with these ligands, with yields between 43 % and 84 %. Using both experimental and computational methods, we examined their structures and photophysical characteristics. Single crystal X‐ray diffraction showed that all eight complexes had distorted tetrahedral geometries. These complexes exhibited photoluminescence with emission bands peaking from 506 nm to 551 nm and quantum yields up to 0.92 at room temperature. Emission lifetimes varied and showed no direct correlation with quantum yields or wavelengths. Physical manipulation and solvent variations significantly altered their photoluminescent properties. DFT and TD‐DFT calculations revealed that higher arsenic content increased spin‐orbit coupling constants, with iodide complexes performing better than bromide ones due to heavier elements enhancing spin‐orbit coupling. Substituting phosphorus with arsenic significantly affected the luminescence quantum yield and lifetime, demonstrating the heavy‐atom effect of arsenic. The position of arsenic in the ligands critically influenced the photophysical outcomes of the CuX complexes.

Studies on enhancement of solubility and dissolution properties of Nimodipine by solid dispersion technique

Nimodipine, a member of calcium channel blocker, specifically binds to L-type voltage-gated calcium channels. The maximum solubility of nimodipine was found at pH 1.2 and solubility decreases up to pH 4.0. At a pH 6.0 and higher pH, solubility reduces drastically. Suitable solid dispersion systems of nimodipine with PVP-K30 and maltodextrin were prepared by physical mixture, solvent evaporation and kneading methods at 1:1 and 1:3 drug: carrier. Drug content, saturation solubility, FTIR, and in-vitro dissolution were studied. The drug content was uniform, solubility of the drug increased linearly as a function of the carrier concentration and method. The FTIR studies indicates no chemical interaction between drug and polymer. The DP60 and DE60 values of solid dispersion systems prepared by solvent evaporation and kneading method were significantly higher (P<0.05) when compared to DP60 and DE60 values of physical mixture and pure Nimodipine. The dissolution follows first order model and obeyed Hixson- Crowell’s cube root law.

Artificial Intelligence in Carbon Capture: Modeling CO2 Absorption Using Amine Blends

Carbon dioxide (CO2) from burning fossil fuels and other modernistic industrial processes is the main contributor to the greenhouse gas impact and global warming. The substantial quantities of CO2 produced by this exercise emphasize the pressing need to produce effective processes for removing it from gas products in order to prevent hazardous emissions into the atmosphere. This work an aim is to develop a predictive model for estimating the CO2 absorbed rate in various amine blends. The model was used an artificial neural network (ANN) with three inputs, which was trained on a dataset of 159 experimental data points associated with CO2 absorption by amine blends. Sterically hindered amines, primary amines, tertiary amines, and a few promoters along with physical solvents were among the amine blends that were taken into consideration. Three crucial input variables that were included in the study: Amine temperature (T), Blended amine concentration (AmH) and the Partial pressure of CO2(PCO2 ), and. RCO2 (unit as, kmol.m−2.s−1), or the rate of CO2 absorption, was the model’s target value. 15 neurons were found to be the ideal count of neural network models, and the dataset’s mean square error (MSE) was found to be 21.18. These findings demonstrated how effectively the created ANN model predicted CO2 absorption rates, representing a crucial step in the processes of carbon capture and sequestration.

Design and characterization of glimepiride hydrotropic solid dispersion to enhance the solubility and dissolution

Background: Glimepiride lowers blood sugar levels in the body, and treats type 2 diabetes mellitus. But the main problem with the drug is its low aqueous solubility. The primary purpose of this study is to increase its solubility in an aqueous medium by using amphiphilic hydrotropic agents instead of harmful, volatile organic solvents. Methodology: A solubility study of Glimepiride was carried out using various hydrotropic agents at 10%, 20%, 30%, and 40%. In mixed hydrography, 30% of the hydrotropic agents were chosen for making blends due to their highest solubility. The blend's solubility was raised more than 50 times at fixed concentrations of urea (20%) and sodium acetate (10%) in a mixed hydrotropic solution. The solubility of Glimepiride in distilled water is 0.0038 mg/ml; in 30% urea, 49.512 ug/ml; and in 30% sodium acetate, 40.43 ug/ml. The optimized blend prepared hydrotropic solid dispersions by physical mixing and solvent evaporation. It was evaluated for drug content, FTIR, SEM, X-ray diffraction, and in vitro drug release studies. Finally, the drug release profile of the prepared tablet is compared with an already available consumer product. Result: HSD-5 showed an in-vitro drug release of 84.77±0.44 at 90 min, which is higher than the remaining formulations, and no significant change was found in drug content or drug release after 15, 30, and 45 days of stability studies. Scanning electron microscopy (SEM) showed homogenous solid dispersion, crystallinity was determined using X-ray diffraction, and FTIR showed good drug compatibility with carriers. The drug release profile of the prepared tablet was higher than that of the available consumer product. Conclusion: This study revealed that hydrotropic agents can potentially increase glimepiride's solubility and drug release. This approach can effectively enhance the solubility of poorly water-soluble drugs.

Formulation, Evaluation and Study of Super Disintegrants effect on Olmesartan Medoxomil Fast Dissolving Tablets

The current research was to enhance solubility and dissolution rate of the slightly soluble drug, Olmesartan medoxomil, solid dispersions by physical mixing, solvent evaporation and kneading techniques, with soluplus. The solid dispersions prepared are tested for flow properties, drug content, and particle size. In vitro dissolution studies were carried out to analyse the drug release from solid dispersions. Crystal morphology, drug and polymer interaction for selected solid dispersions was studied by FT-IR and DSC analysis. Fast-dissolving tablets were formulated by using optimized solid dispersions using different concentrations of sodiumstarch glycolate, crosscarmellosesodium, and crospovidone as superdisintegrants using direct compression technique. The tablets prepared are tested for Weight variation, friability, disintegration, content uniformity and harness. The mechanism and kinetics of drug release from the fast-dissolving tablets were tested by in-vitro dissolution studies. The current research proves that combining solid dispersions along with the use of superdisintegrants is novel approach to formulate of Olmesartan medoxomil fast-dissolving tablets.

Solubility Enhancement of Efinaconazole using Neem Gum and Evaluation of Antifungal Activity

Objectives: Efinaconazole is an anti-fungal drug of BCS class II used for treating Onchomycosis. Neem gum known for its antifungal properties was purified and used as hydrophilic carrier. Solid dispersions by physical mixture and solvent evaporation method were prepared using purified Neem gum. Methods: The prepared solid dispersions in ratios 1:1, 1:3 and 1:6 were characterized for percentage yield, assay, solubility, and dissolution studies. The optimized solid dispersion SD6 was formulated as gel for ease of application. Gels were characterized for physico-chemical properties and in-vitro diffusion studies. The optimized gel was evaluated for anti-fungal activity. Findings: FTIR, DSC and XRD studies of optimized SD6 showed compatibility and amorphous nature respectively. G2 gel formulation containing SD6 solid dispersion showed 80.4±0.14% when compared to G1 56.76±0.34% release in 8hrs. Both the gels followed zero order and Higuchi release. Antifungal studies indicated more efficiency of G2 gel by zone of inhibition when compared with G1 containing only drug. G2 gel was found to be stable for one month. Novelty : In the present research work purified neem gum, which is natural carrier and neem known for its antifungal activity was used to enhance the solubility of drug and evaluate the antifungal activity of drug with purified neem gum. Conclusion: Hence it can be concluded, purified Neem gum can be used as hydrophilic carrier and as solubility of Efinaconazole was enhanced its antifungal activity was also increased. Keywords: Onchomycosis, Efinaconazole, Neem gum, Solid dispersions, Antifungal

Conductive Co1.5MoS3.2 promoted photocatalytic H2 production over g-C3N4.

In this work, Co1.5MoS3.2 (CMS) nanoparticles were synthesized using a one-step hydrothermal approach, series CMS/g-C3N4 photocatalysts with various CMS amount were obtained using a physical solvent evaporation method. The investigation indicates that introducing CMS as cocatalysts can greatly enhance the H2 production activity of g-C3N4 by two orders of magnitude. The H2 production rate reaches up to 17607 μmol·g−1·h−1 over 40 wt% CMS/g-C3N4, resulting in a 185-fold increase when compared to the unmodified g-C3N4 (94.8 μmol·g−1·h−1), far better than 40 wt% MoS2/g-C3N4 (125.2 μmol·g−1·h−1), 40 wt% Co3S4/g-C3N4 (7948.6 μmol·g−1·h−1), even widely 3 wt% Pt/g-C3N4 (12803 μmol·g−1·h−1). The improvement can be ascribed to the Schottky junction effect between CMS and g-C3N4, the highly conductive CMS can receive electrons from the conduction band of g-C3N4, preventing charge recombination. Meanwhile, CMS can obviously lower the H2 evolution potential and provide more active site for the H2 evolution reaction, those all lead to a faster H2 evolution kinetics. Additionally, CMS as a cocatalyst offers advantages such as simple preparation, low cost, and remarkable effectiveness, making it highly promising for further development.

Selective CO2 separation through physicochemical absorption by triazole‐functionalized ionic liquid binary absorbents

AbstractThe selective separation of CO2 from CH4‐containing gases is crucial to produce clean energy gases. In this study, triazole anion‐functionalized ionic liquids (TAFILs) were designed by combining low molecular weight cations with triazole anions containing N electronegative site and further mixed with physical solvents to form physicochemical absorbents. The results indicated that [Cho][Triz]/TMS (80 wt%/20 wt%) not only absorbs 0.125 g CO2/g absorbent equal to that of 30 wt% MEA solution at 40°C and 1 bar, but also has low enthalpy of −35.76 kJ/mol less than half of 30 wt% MEA solution. Simultaneously, a super high CO2/CH4 selectivity of 191.0, higher than most of the reported absorbents, is obtained for [Cho][Triz]/TMS solvents. Such great performance of CO2 separation was attributed to relatively weak chemical and physical interaction between CO2 and TAFIL binary absorbents. This study may provide novel promising ionic liquid absorbents for CO2 capture applications from clean energy gases.

DESIGN AND DEVELOPMENT OF ANTI-INFLAMMATORY DRUG NAPROXEN SOLID DISPERSIONS AND FORMULATIONS BY FACTORIAL DESIGN APPROACH

Naproxen is a non-steroidal anti-inflammatory (NSAID) drug that can be used as an analgesic, anti-inflammatory, and antipyretic. Objectives: The study’s major goal was to improve the drug’s solubility and dissolution rate, as well as its oral bioavailability. Methods: Physical mixture, kneading process, and solvent evaporation method were used to make Naproxen solid dispersions (SDs). Using a two-level factorial design and three independent components, X1 β-Cyclodextrin, X2: Kolliphor p-188, and X3: PVPK-30 and designed by a Design expert (DOE). The formulation was studied by flow parameters, physical characteristics, Fourier-transform infrared spectroscopy, and comparative investigations with commercially available Naprosyn and F2. Major Results: In vitro performance of solid dispersions SD’s was favorable (100% drug release 20 minutes), compared to a pure drug, where 100 percent drug release takes 80 minutes. The FTIR spectra of pure drug and combinations with excipients were having no chemical interaction. The F44<F88<F77<F11<F66<F55<F33<F2 depicts the order of released various formulations. The release profiles of F2 and the Naprosyn tablet are similar. These findings suggest that a new naproxen tablet formulation, including the β-Cyclodextrin: Kolliphor - p188 complex, could be a viable alternative for improving oral bioavailability.

High-pressure carbon dioxide solubility in a deep eutectic solvent (Choline Chloride/MDEA) + sulfolane—Experimental study and thermodynamic modeling using PC-SAFT equation of state

In recent years, releasing post-combustion CO2 into the atmosphere has led to global warming. Air contamination has appeared as a challenge for governments, so several approaches have been used to overcome this issue. So far, physical and chemical solvents have been employed by researchers for CO2 capture. These years deep eutectic solvents (DES) have emerged as an alternative to traditional solvents. In this study, we have investigated a mixture of DES + a physical solvent for the CO2 solubility measurement using a static vapor-liquid equilibrium cell. In this work, the DES was composed of Choline Chloride and MDEA in a molar ratio of 1 to 6 which is blended with sulfolane in weight percentages of 5,10, and 15. We performed the experiments at temperatures of 323.15, 333.15, and 343.15 K and a pressure range of up to 5 MPa. In our previous work, we had already investigated the influence of piperazine on the present DES that led to enhancing CO2 absorption in the mixture, while adding sulfolane to the DES in the present work does not present a positive effect on CO2 solubility in the DES. Enhancing pressure and reducing temperature also led to increasing CO2 solubility. Finally, we modeled the solubility data with the PC-SAFT equation of state. The modeling results were in excellent agreement with the experimental data for DES-CO2, DES-sulfolane-CO2, and DES-piperazine-CO2 systems, so the PC-SAFT EoS successfully estimated the carbon dioxide solubility in the present systems with the absolute average deviation percent of less than unity.

Physical vapor deposition of an oriented metal–organic framework HKUST-1 thin film on an insulating substrate

This study reports the synthesis of a (111)-oriented HKUST-1 ([Cu3(BTC)2], BTC = 1,3,5-benzenetricarboxylate) thin film on an insulating glass substrate using a combination of physical vapor deposition and solvent vapor annealing.

Improvement of in vitro dissolution profile of poorly aqueous soluble anti-parasitic agent ivermectin using novel hydrophilic polymeric carriers

Ivermectin (IVM), a BCS Class II drug with weak water solubility, has minimal oral absorption and dissolution. This study aims to enhance the dissolution profile of IVM by performing solid dispersion methods using four hydrophilic polymers: Kollicoat IR, Kollidon 90F, poloxamer 407, and hydroxypropyl methylcellulose (HPMC). The solid dispersion formulations (SDF) were made through physical mixing, solvent evaporation, and melt solvent/fusion. Using three ratios of IVM and hydrophilic carriers (1:1, 1:2, and 1:3), the cumulative release rate of IVM from formulations formed by physical mixing, solvent evaporation, and fusing was much larger than pure IVM (10%). IVM release rates from formulations including Poloxamer 407, Kollicoat IR, and HPMC polymers were 76% (fusion technique), 69% (physical mixing), and 47% (solvent evaporation method). The research demonstrated that fusion optimized drug solubility better than physical mixing and solvent evaporation. The research found that SD of weakly water-soluble IVM with Kollicoat IR/Poloxamer 407 improves its in vitro dissolving profile much better. Bangladesh J. Sci. Ind. Res. 58(4), 209-220, 2023

A low energy-consuming phase change absorbent of MAE/DGM/H2O for CO2 capture

The concept of phase change absorbents has been widely studied as a novel and low-energy consumption option for CO2 capture. This work screened diethylene glycol dimethyl ether (DGM) from 17 physical solvent species as a better phase change accelerator for absorbents of 2-(methylamino)ethanol (MAE)-physical solvent-H2O. Then, the optimized mass ratio of 30:49:21 for MAE-DGM-H2O solution was investigated with phase change behaviors, CO2 absorption–desorption performance, cyclic capacity, and energy consumption. The experimental results showed that the cyclic CO2 capacity reached 1.32 mol/L and the CO2-rich phase made up only 50.4 % of the total volume for the 30 wt%MAE-49 wt%DGM-21 wt%H2O, as well as its regenerative energy consumption was 40 % lower than that of 30 wt% monoethanolamine (MEA) solution. Also, the viscosity and surface tension gap of the CO2-rich phase and CO2-lean phase for the optimized absorbent were studied. It was observed that those gaps increase with the increasing mass ratio of DGM. In addition, the possible phase change mechanism was proposed by using the dipole moment values of components calculated by Gaussian (B3LYP/6-31G) coupled with 13C NMR spectra.