Search Results (484)

Background/Objectives: MHY498, a tyrosinase inhibitor, exhibits poor water solubility, which limits its topical delivery. Despite the importance of solubility data in rational formulation design, comprehensive information on its solubility behavior in various solvents and across a range of temperatures remains limited. Thus, this study aimed to systematically evaluate the solubility characteristics of MHY498 and to develop a nanosuspension formulation using an antisolvent precipitation approach to facilitate the development of an optimized topical formulation. Methods: In this study, we measured the solubility of MHY498 in various monosolvents and diethylene glycol monoethyl ether (DEGME) + water solvent mixtures at 293.15–313.15 K using a solid–liquid equilibrium technique. Based on these solubility data, MHY498 nanosuspensions were prepared via antisolvent precipitation guided by a Box–Behnken design matrix. In vitro skin permeability was also assessed using a Franz diffusion cell system to assess the topical delivery potential of the MHY498 nanosuspensions. Results: Among the investigated monosolvents, MHY498 exhibited the highest solubility in dimethylformamide, dimethylacetamide, DEGME, while the lowest solubility was observed in water. The solubility increased with temperature and DEGME content in solvent mixtures, and the experimental data were well described by thermodynamic and semi-empirical models, indicating an endothermic and spontaneous dissolution process. Solvent–solute interaction analysis revealed that hydrogen-bonding and nonspecific polarity interactions played key roles in enhancing MHY498 solubility. All nanosuspensions prepared within the design space exhibited particle sizes below 150 nm, and the optimized formulation achieved an average particle size of 28.1 nm. The optimized nanosuspension demonstrated a 3.3-fold increase in the cumulative permeated amounts compared with the conventional microsuspension. Conclusions: These findings demonstrate that a rational solvent selection strategy based on thermodynamic solubility analysis and antisolvent precipitation enables effective nanosuspension formulation of MHY498. The DEGME–water system was identified as a formulation-relevant solvent environment that supports both adequate drug solubilization and reproducible formation of nanosized particles. The resulting nanosuspension exhibited favorable particle size characteristics and enhanced formulation feasibility for topical applications. Therefore, it was shown that the developed nanosuspension system, established through a solubility-driven systematic approach, represents a promising strategy for improving topical delivery of MHY498. Full article

Solubility studies are an essential requirement for the development of more efficient industrial processes. In this context, the use of cosolvents is a relevant strategy in pharmaceutical sciences, especially when dealing with green solvents such as water (W (2)) and Polyethylene glycol 400 (PEG 400 (1)). The objective of this study is to thermodynamically analyze the solubility of isoniazid in {PEG 400 (1) + W (2)} cosolvent mixtures at seven temperatures (288.15 to 318.15 K). The study was conducted by calculating thermodynamic functions from experimental solubility data determined using the flask shaking method, employing UV spectrophotometry as the quantification technique. The dissolution process was shown to be endothermic and entropy-driven. Although maximum solubility would be expected to be achieved in a cosolvent mixture, given that the solubility parameter of isoniazid (30.54 MPa^1/2) has an intermediate value between the two pure solvents (PEG 400 ≈ 22.5 MPa^1/2; Water $\approx 47.8$ MPa^1/2), maximum solubility is achieved in pure PEG 400 and the lowest solubility is achieved in pure water. Full article

Lithium is an essential material for lightweight batteries. Traditional mining of soluble salts expanded to include the extraction of hard rocks, which requires their solubilization through roasting. Among hard lithium rocks, spodumene has recently received attention from the scientific community. Its metallurgical processing can be classified according to the type of reagents, as well as the operating temperature and pressure. The use of calcium carbonate as a natural alkali avoids aggressive chemicals such as sulfuric acid or caustic soda. In this article, 0.5 g of jewelry-grade spodumene was loaded into a ceramic crucible with 2.5 g of reducing agent in a tandem of roasting at 1050 °C-1 bar-30 min and leaching with neutral water at 90 °C-1 bar-20 min at a water/clinker mass ratio of 25. Measurements by XRD, ICP-OES, and SEM-EDX suggest a pathway of spodumene cracking because of poor contact with the reductant. Potassium present in the crucible acts as a flux and encapsulates spodumene crystals, causing lithium to end up bound to silica. While lithium metasilicate is barely soluble in water, leaching potassium aluminate hoards in the liquid. The empirical observations were supported with thermodynamic spontaneity studies, which required compiling the mineral properties based on open reference tabulations. Full article

Lead–bismuth eutectic (LBE), while advantageous for advanced nuclear reactors due to its thermophysical properties, faces oxidation and corrosion challenges during operation. This study aims to optimize gas-phase oxygen control by computationally analyzing oxygen transport dynamics in an LBE loop. High-fidelity simulations were performed using ANSYS Fluent and STAR-CCM+ based on the CORRIDA loop geometry, employing detailed meshing for convergence. Steady-state analyses revealed localized oxygen enrichment near the gas–liquid interface (peaking at ∼$3\times {10}^{-6}$ wt%), decreasing to ∼$5.0-6.8\times {10}^{-8}$ wt% at the outlet. Transient simulations from an oxygen-deficient state ($1\times {10}^{-8}$ wt%) demonstrated distribution stabilization within 150 s, driven by convection-enhanced diffusion. Parametric studies identified a non-monotonic relationship between inlet velocity and oxygen uptake, with optimal performance at 0.7–0.9 m/s, while increasing temperature from 573 K to 823 K monotonically enhanced the outlet concentration by >$200\%$ due to improved diffusivity/solubility. The average mass transfer coefficient (0.6–0.7) aligned with literature values ($\pm 20\%$ deviation), validating the model’s treatment of interface thermodynamics and turbulence. These findings the advance mechanistic understanding of oxygen transport in LBE and directly inform the design of oxygenation systems and corrosion mitigation strategies for liquid metal-cooled reactors. Full article

Headspace (HS) in anaerobic batch biodigesters is a critical design parameter that modulates pressure stability, gas–liquid equilibrium, and methanogenic productivity. This systematic review, guided by PRISMA 2020, analyzed 84 studies published between 2015 and 2025, of which 64 were included in the qualitative and quantitative synthesis. The interplay between headspace volume fraction ${\mathrm{V}}_{\mathrm{H}\mathrm{S}}/{\mathrm{V}}_{\mathrm{t}\mathrm{o}\mathrm{t}}$, operating pressure, and normalized methane yield was assessed, explicitly integrating safety and instrumentation requirements. In laboratory settings, maintaining a headspace volume fraction (HSVF) of 0.30–0.50 with continuous pressure monitoring P(t) and gas chromatography reduces volumetric uncertainty to below 5–8% and establishes reference yields of 300–430 NmL CH₄ g⁻¹ VS at 35 °C. At the pilot scale, operation at 3–4 bar absolute increases the CH₄ fraction by 10–20 percentage points relative to ~1 bar, while maintaining yields of 0.28–0.35 L CH₄ g COD⁻¹ and production rates of 0.8–1.5 Nm³ CH₄ m⁻³ d⁻¹ under OLRs of 4–30 kg COD m⁻³ d⁻¹, provided pH stabilizes at 7.2–7.6 and the free NH₃ fraction remains below inhibitory thresholds. At full scale, gas domes sized to buffer pressure peaks and equipped with continuous pressure and flow monitoring feed predictive models (AUC > 0.85) that reduce the incidence of foaming and unplanned shutdowns, while the integration of desulfurization and condensate management keep corrosion at acceptable levels. Rational sizing of HS is essential to standardize BMP tests, correctly interpret the physicochemical effects of HS on CO₂ solubility, and distinguish them from intrinsic methanogenesis. We recommend explicitly reporting standardized metrics (Nm³ CH₄ m⁻³ d⁻¹, NmL CH₄ g⁻¹ VS, L CH₄ g COD⁻¹), absolute or relative pressure, HSVF, and the analytical method as a basis for comparability and coupled thermodynamic modeling. While this review primarily focuses on batch (discontinuous) anaerobic digesters, insights from semi-continuous and continuous systems are cited for context where relevant to scale-up and headspace dynamics, without expanding the main scope beyond batch systems. Full article

Background/Objectives: Advancing information on the key physicochemical properties of biologically active substances enables the development of formulations with reduced dosing, lower toxicity, and minimal adverse effects. This work addresses the knowledge gap concerning the pharmacologically relevant properties of harmaline (HML), with a focus on thermodynamic and kinetic aspects. New data were obtained on the compound’s solubility and distribution coefficients across a wide temperature range. Specifically, solubility was measured in aqueous buffers (pH 2.0 and 7.4), 1-octanol (OctOH), n-hexane (Hex), and isopropyl myristate (IPM), while distribution coefficients were determined in OctOH/pH 7.4, Hex/pH 7.4, and IPM/pH 7.4 systems. Methods: Three membranes—regenerated cellulose (RC), PermeaPad (PP) and polydimethylsiloxane-polycarbonate (PDS)—were used as barriers in permeability studies using a Franz diffusion cell. Results: At 310.15 K, the molar solubility of HML in the solvents decreased in the following order: OctOH > pH 2.0 > pH 7.4 > IPM > Hex. The distribution coefficient of HML showed a strong dependence on the nature of the organic phase, correlating with its solubility in the respective solvents. The OctOH/pH 7.4 distribution coefficient ranged from 0.973 at 293.15 K to 1.345 at 313.15 K, falling within the optimal range for potential drug bioavailability. The transfer of HML into OctOH (from either pH 7.4 or hexane) is thermodynamically spontaneous, whereas its transfer into Hex is unfavorable. Conclusions: Based on its permeability across the PP barrier, HML was classified as highly permeable. The distribution and permeation profiles of HML showed similar trends over 5 h in both the OctOH/pH 7.4–PP and IPM/pH 7.4–PDS systems. These systems were therefore proposed as suitable models for studying HML transport in vitro. Full article

The inhibitory effects of natural cellulose (NC), microcrystalline cellulose (MC), and soluble fiber dextrin (SC) on amylase activity have been established; however, the underlying mechanisms remain poorly understood. This study employed fluorescence spectroscopy and fluorescence thermodynamics to investigate the quenching parameters, thermodynamic properties, and quenching mechanisms of cellulose interactions with α-amylase and amyloglucosidase. Structural alterations in both enzymes were examined using synchronous fluorescence and UV–visible absorption spectroscopy. The results indicated that NC, MC, and SC primarily induced static quenching of fluorophores in α-amylase and amyloglucosidase. When addition of SC reached 3%, SC reduced the fluorescence intensity of tyrosine and tryptophan residues in α-amylase by 70.9% and 86.8%, and in amyloglucosidase by 43.7% and 46.5%, respectively. Increasing SC levels also decreased hydrophobicity around tyrosine and tryptophan in α-amylase. These findings provide insights into designing cellulose-based amylase inhibitors through structural modulation for developing low-glycemic index (GI) foods. Full article

Carbon Capture, Utilization and Storage (CCUS) is a critical area of research due to its potential to significantly reduce CO₂ emissions from industrial processes and fossil fuel-based power generation. Aqueous amine solutions are commonly used as chemical solvents for CO₂ capture. However, their application is disfavoured by the high energy requirements and related operational costs, toxicity, and corrosion issues. To address these limitations, research is in general focused on developing novel solvents that can overcome the drawbacks of traditional amines. This development needs the study of phase equilibria in systems for which detailed physicochemical data are often scarce in the literature. In particular, understanding the solubility of gases (CO₂) in possible solvent mixtures is essential for evaluating their suitability for chemical or physical absorption processes. In this work, a dedicated setup was installed to generate the experimental data for these novel systems. This unit was designed to measure the solubility and diffusivity of gases in low-volatility liquids that could be alternative CO₂ solvents. A detailed experimental procedure was established, and the unit was initially validated by measuring CO₂ solubility in a 30 wt% monoethanolamine (MEA) solution, one of the most widely used industrial solvents. The experiments were conducted under conditions representing both the absorption and the regeneration sections of a CO₂ removal plant. The resulting equilibrium data were analyzed by employing several thermodynamic models, and the model providing the best representation was selected. Full article

The solubilities of 498 datasets of N₂O and ionic liquid systems were predicted using a multilayer perceptron. The data used to train the artificial neural network was subjected to the Gibbs–Duhem test to analyze their thermodynamic consistency. The Peng–Robinson cubic equation of state, combined with the Kwak–Mansoori mixing rule, was used as the thermodynamic model to implement the test. The analysis indicated that 71.9% of the data were declared thermodynamically inconsistent. The ability of artificial neural networks (ANNs) to predict the solubility of these systems using experimental datasets that do not satisfy the thermodynamic consistency criteria based on the Gibbs–Duhem equation was studied. The multilayer perceptron model achieved an average absolute deviation of 1.81% and a maximum individual deviation of 7.56%. These results highlight the potential of ANNs as robust predictive tools even when the available data do not fully satisfy thermodynamic consistency criteria. Full article

Birnessite has a strong ability to fix rare-earth elements (REEs), but the transformation process of birnessite and its effects on the migration of these elements are not well understood. This study examines how pH and Mn(II) concentrations influence the transformation of cerium-adsorbed hexagonal birnessite (Ce/HB) and the behaviors of Ce and Mn. The results show that the effect of Mn(II) on Ce/HB transformation strongly depended on solution pH. At a pH of 5.0, HB initially underwent transformation into feitknechtite, followed by further disproportionation that resulted in the regeneration of HB and Mn(II). Concurrently, redox reactions occur between Mn(IV) in MnO₂ (a secondary phase of HB) and Ce(III)/Mn(II), creating a local redox gradient that facilitates partial HB transformation. At pH = 7.0, Mn(II) reduces the crystallinity of transformed products while enhancing the thermodynamic stability of feitknechtite, making it the dominant manganese oxide phase. At pH = 9.0, high-concentration Mn(II) causes lattice distortion in original HB; Ce(III) acts as a structural inducer, promoting mineral transition from hexagonal to orthorhombic symmetry, while excess soluble Mn(II) precipitates new feitknechtite. Additionally, surplus Mn(II) could engage in interfacial redox reactions with high-valent manganese oxides to generate secondary feitknechtite. Ce primarily exists as Ce(IV), forming CeO₂ on the mineral surface via oxidation reactions that significantly increase hydroxylation and surface reactivity. This study clarifies the transformation pathways of manganese oxides and the migration and transformation patterns of Ce and Mn in rare-earth-rich mining areas. Full article

Hot-melt extrusion produces a solid dispersion (SD) containing a poorly water-soluble drug (k) and matrix polymer surfactant (PS), thereby enhancing k’s solubility. When dissolving the SD, the PS is first dissolved, forming micelles. The amorphous form of the solid phase k remains and is further dissolved by micellar solubilization. The goal here is to rigorously derive, on the basis of thermodynamics, a new expression for the change in the standard Gibbs free energy (${∆G}_{\Sigma }^0$). This change serves as a measure for increasing the degree of spontaneity in the dissolution of amorphous k from an SD with a polymeric surfactant relative to the dissolution of the crystalline-form k in an aqueous solution without surfactants (reference state). In the micelle-pseudophase model, it was found that ${∆G}_{\Sigma }^0$ depends on the natural logarithm of the ratio of mole fraction k in the aqueous phase to mole fraction k in the micellar pseudophase. In a simpler model, ${∆G}_{\Sigma }^0$ can be expressed as ln of the solubility ratio of the crystalline and SD forms, assuming that the activity coefficient depends on the process of incorporating k into the micellar particles and that the total amount of surfactants is many times smaller than the water amount, which is acceptable for polymeric surfactants with low values of the critical micellar concentration. Full article

Antioxidants are essential bioactive compounds widely recognized for their health benefits in preventing oxidative stress-related diseases. However, many lipophilic antioxidants suffer from poor aqueous solubility, low chemical stability, and limited bioavailability, restricting their application in food, nutraceutical, and pharmaceutical industries. Cyclodextrins (CDs), a class of cyclic oligosaccharides with a hydrophilic exterior and lipophilic interior, present an effective strategy to encapsulate and deliver these compounds by improving their solubility, stability, and therapeutic efficacy. This review critically examines the structural features and derivatives of cyclodextrins relevant for antioxidant encapsulation, mechanisms and thermodynamics of inclusion complex formation, and advanced characterization techniques. It evaluates the influence of CD encapsulation on the oral bioavailability and antioxidant activity of various lipophilic antioxidants supported by recent in vitro and in vivo studies. Moreover, sustainable preparation methods for CD complexes are discussed alongside safety and regulatory considerations. The comprehensive synthesis of current knowledge contributes to guiding the rational design and development of CD-based antioxidant nutraceuticals, addressing formulation challenges while promoting efficacy and consumer safety. Full article

The photocatalytic reduction of CO₂ in aqueous media offers a sustainable route for solar-to-fuel conversion, yet remains challenged by CO₂’s thermodynamic stability and kinetic inertness, low solubility, and competitive hydrogen evolution. Here, we investigate the interplay between ionic liquids (ILs), photocatalyst supports, and additive composition in directing product selectivity among CO, CH₄, and H₂. Using imidazolium acetate as a benchmark, we demonstrate that ILs not only pre-activate CO₂ but can also undergo decomposition pathways under illumination, notably Kolbe-type reactions leading to methane formation from acetate rather than from CO₂. Comparative studies of Pd-decorated TiO₂ and g-C₃N₄ nanosheets reveal distinct behaviors driven by their interfacial interactions with the imidazolim-based ionic liquid: weak interaction with TiO₂ strongly promotes hydrogen evolution, whereas strong coupling with g-C₃N₄ synergizes with C₁C₄ImOAc to trigger acetate-derived Kolbe reactivity. The systematic evaluation of alternative salts confirms the determinant role of anion basicity and medium-pH-basic anions facilitate CO₂ activation, whereas weakly basic or non-coordinating anions favor water splitting. Overall, these results clarify the dual role of ionic liquids as both CO₂ activators and sacrificial agents, and highlight design principles for improving product selectivity and efficiency in aqueous CO₂ photoreduction systems. Full article

Copper anode slime (CAS), obtained from non-standard anodes by pyro-hydrometallurgical electronic waste (e-waste) processing, contains high concentrations of lead, tin (as metastannic acid), and base (Cu, Fe, Zn), precious (Au, Ag), and technological metals (In, Ga, Ge), which limit the efficiency of conventional valorization methods. In this study, an integrated alkali fusion–leaching process was applied to non-standard CAS. Thermodynamic modeling defined the key parameters for selective phase transformations and efficient metal separation. These parameters were experimentally investigated, and the optimized fusion conditions (CAS:NaOH = 40:60, 600 °C, 60 min), followed by water leaching (200 g/dm³, 80 °C, 60 min, 250 rpm), resulted in >97% Sn removal efficiency. Simultaneously, Au and Ag losses were negligible, resulting in solid residue enrichment. Oxidant addition (NaNO₃) did not improve Sn removal but increased Fe, Pb, and Ag solubility, reducing selectivity. The scaled-up test confirmed process reproducibility, achieving 97.75% Sn dissolution and retention of precious metals in the PbO-based residue (99.99% Au, 99.78% Ag). Application of an integrated thermodynamic modeling, laboratory optimization, and scaled-up validation approach to non-standard CAS provides a relevant framework for a selective, efficient, and scalable method addressing industrial needs driven by increased e-waste co-processing, contributing to sustainable metal recovery. Full article

Sinomenine Hydrochloride is a bioactive alkaloid extracted from the root and stem of the medicinal plant sinomenium acutum, and is widely used to treat rheumatoid arthritis. Relevant studies were consulted, and the solubility data of Sinomenine Hydrochloride in ethanol–water mixed solvent have not been reported. It is essential to choose a proper solvent in the process of crystallization that has a significant influence on the purity and productivity. Therefore, it is necessary to determine the solubility of Sinomenine Hydrochloride under the conditions of different ratios of ethanol–water mixed solvent and temperature. In this study, the solubility of Sinomenine Hydrochloride in ethanol–water mixed solvent was determined using high-performance liquid chromatography within the temperature range of 283.15 K–308.15 K. At the same time, the CNIBS/R-K model, Modified Apelblat model, Yaws model, and Apelblat–Jouyban–Acree model were used to fit the solubility data, and the relevant thermodynamic parameters were calculated using the Van’t Hoff model. The results showed that the solubility of Sinomenine Hydrochloride was higher in pure water than in pure ethanol. Moreover, with the increase in the mass fraction of ethanol in the mixed solvent, the solubility of Sinomenine Hydrochloride showed a trend of increasing first and then decreasing. When the ethanol–water ratio was 5:5, the solubility of the compound reached the maximum. In addition, experimental data showed that the solubility of Sinomenine Hydrochloride was affected by temperature. In the experimental temperature range, the solubility increased with the increase in temperature. Among these four solubility models, the CNIBS/R-K model had the best fitting effect; the maximum RAD and RMSD were 4.622 × 10⁻³ and 4.079 × 10⁻³, respectively. The thermodynamic model fitting results showed that the predicted values were in good agreement with the experimental data, and the thermodynamic parameters ΔHd, ΔSd, and ΔGd were all positive values. This indicated that the dissolution of Sinomenine Hydrochloride in the ethanol–water mixture was a non-spontaneous and endothermic process. A proper ratio of ethanol–water and temperature improved the solubility of Sinomenine Hydrochloride. The data determined in this study can provide basic data for the industrial purification of Sinomenine Hydrochloride. Full article