Search Results (130)

L-arginine, a basic amino acid, exhibits high biocompatibility, reactivity, and absorbability. It was selected as the co-polymer modification monomer for L-lactic acid with the objective of enhancing the hydrophilicity of poly(lactic acid) (PLA), neutralizing the acidity of PLA degradation products, and regulating the degradation cycle. The copolymer poly(lactic acid-co-arginine) (PLAA) was synthesized by direct melting polycondensation of L-arginine and L-lactic acid, and the structures and properties of PLAA were characterized. The results indicated the presence of –NH₂, –NH–, and NH= in the molecular chain of the copolymer PLAA. Furthermore, the PLAA was identified as an amorphous copolymer. The “PLAA/CHCl₃/C₆H₁₄” ternary phase diagram was constituted by nonsolvent-induced phase separation (NIPS) by selecting chloroform (CHCl₃) as a good solvent and n-hexane (C₆H₁₄) as a nonsolvent. The phase diagram displays three distinguishable regions: the homogeneous zone, the metastable zone, and the phase separation zone. These regions are identified by the binodal and spinodal curves. The ternary phase diagram establishes a theoretical foundation for the preparation and processing of PLAA nanoparticles, composite materials, and porous fibers or membranes. Full article

Alkali resistance is a critical factor for the long-term performance of glass fibers in cementitious composites. While zirconium oxide doping has proven effective in enhancing the durability of basalt fibers, its high cost and limited solubility motivate the search for viable alternatives. This study presents the first systematic investigation of titanium dioxide (TiO₂) doping in basalt-based glasses across a wide compositional range (0–8 mol%). X-ray fluorescence and diffraction analyses confirm complete dissolution of TiO₂ within the amorphous silicate network, with no phase segregation. At low concentrations (≤3 mol%), Ti⁴⁺ acts as a network modifier in octahedral coordination ([TiO₆]), reducing melt viscosity and lowering processing temperatures. As TiO₂ content increases, titanium in-corporates into tetrahedral sites ([TiO₄]), competing with Fe³⁺ for network-forming positions and displacing it into octahedral coordination, as revealed by Mössbauer spectroscopy. This structural redistribution promotes phase separation and triggers the crystallization of pseudobrukite (Fe₂TiO₅) at elevated temperatures. The formation of a protective Ti(OH)₄ surface layer upon alkali exposure enhances chemical resistance, with optimal performance observed at 4.6 mol% TiO₂—reducing mass loss in NaOH and seawater by 13.3% and 25%, respectively, and improving residual tensile strength. However, higher TiO₂ concentrations (≥5 mol%) lead to pseudobrukite crystallization and a narrowed fiber-forming temperature window, rendering continuous fiber drawing unfeasible. The results demonstrate that TiO₂ is a promising, cost-effective dopant for basalt fibers, but its benefits are constrained by a critical solubility threshold and structural trade-offs between durability and processability. Full article

Amorphous solid dispersions (ASDs) represent a promising formulation strategy for improving the solubility and bioavailability of poorly water-soluble drugs, a major challenge in pharmaceutical development. This review provides a comprehensive analysis of the physicochemical principles underlying ASD stability, with a focus on drug–polymer miscibility, molecular mobility, and thermodynamic properties. The main manufacturing techniques including hot-melt extrusion, spray drying, and KinetiSol^® dispersing are discussed for their impact on formulation homogeneity and scalability. Recent advances in excipient selection, molecular modeling, and in silico predictive approaches have transformed ASD design, reducing dependence on traditional trial-and-error methods. Furthermore, machine learning and artificial intelligence (AI)-based computational platforms are reshaping formulation strategies by enabling accurate predictions of drug–polymer interactions and physical stability. Advanced characterization methods such as solid-state NMR, IR, and dielectric spectroscopy provide valuable insights into phase separation and recrystallization. Despite these technological innovations, ensuring long-term stability and maintaining supersaturation remain significant challenges for ASDs. Integrated formulation design frameworks, including PBPK modeling and accelerated stability testing, offer potential solutions to address these issues. Future research should emphasize interdisciplinary collaboration, leveraging computational advancements together with experimental validation to refine formulation strategies and accelerate clinical translation. The scientists can unlock the full therapeutic potential with emerging technologies and a data-driven approach. Full article

High-silica–alumina coal gangue is rich in kaolinite, quartz, and other mineral components. The potential for resource utilization is huge, but the silica–aluminate structure is highly stable, and it is difficult to achieve efficient dissociation and elemental enrichment using traditional extraction processes. This study selects typical high-silica–alumina coal gangue as the research object and systematically studies the rules of the physical phase transformation mechanism and ion migration behavior in the activation process of the sodium-based additives stage. In addition, a graded leaching and separation processing route is established, realizing the effective separation and extraction of silica–alumina. The key parameters were optimized using response surface methodology (RSM), obtaining the optimal activation conditions of 800 °C, 30 min, and an additives ratio of 0.8. Under these conditions, the highest dissolution rates of silica and alumina are 82.1% and 92.36%, respectively. Characterization techniques such as XRD, FTIR, and SEM reveal that the activation mechanism of coal gangue involves the decomposition of the aluminosilicate framework and the erosion of sodium ions. At the same time, the chemical bonding reorganization contributes to forming water-soluble sodium silicate (Na₂SiO₃) and insoluble nepheline (NaAlSiO₄), which significantly promotes the release of Si and Al. When the activation temperature is too high, the nepheline phase is transformed into amorphous glassy sodium aluminate and precipitated on the surface, which gradually encapsulates the sodium silicate. This encapsulation restricts dissolution pathways, thereby leading to system densification. Moreover, enhanced resistance to acid attack leads to a decrease in the dissolution rates of Si and Al. This study elucidates the mineral phase reconstruction and element migration mechanisms involved in sodium-based activation and presents a viable approach for the high-value utilization of coal gangue. Full article

Objectives: Transforming poorly soluble crystalline drugs into their amorphous form is a well-established strategy in pharmaceutical science to enhance their solubility and improve their clinical efficacy. However, developing amorphous forms of organic drugs for pharmaceutical applications presents significant technical hurdles due to the lack of suitable analytical tools for the amorphization process. Carbamazepine is a crystalline BCS class II drug commonly used for epilepsy and trigeminal neuralgia, whose clinical efficacy is compromised by its low solubility and slow dissolution. Therefore, this study focuses on investigating the amorphization of carbamazepine to enhance its solubility by using a micro-droplet precipitation system. Methods: These micro-droplets serve as individual reactors, enabling homogeneous nucleation for precipitation of carbamazepine. During crystallization, carbamazepine undergoes an intermediate liquid–liquid phase transition characteristic of two-step nucleation. By varying the solvent’s composition (methanol/water), we characterized the kinetics and stability of the intermediate liquid phase under various conditions. Results: Our results indicate that carbamazepine can undergo either a one-step liquid-to-amorphous-solid phase transition or a two-step liquid-to-crystalline-solid phase transition. Notably, both transitions pass through a liquid-to-dense-liquid phase separation process starting from the supersaturated solution, where the generated intermediate phases exhibit different sizes and numbers that are influenced by the solvent and its concentration. Conclusions: Our findings not only elucidate the mechanism underlying the carbamazepine phase transition but also propose a novel method for studying the amorphous process, which could be broadly applicable to other poorly soluble pharmaceutical compounds and may be helpful to amorphous formulations production, potentially offering significant improvements in drug efficacy and patient compliance. Full article

Background/Objectives: Parenteral nutrition (PN) supports patients unable to receive nutrients via the gastrointestinal tract, but it lacks the health-promoting natural bioactive compounds found in a typical oral diet. This study aimed to develop a human serum albumin-based intravenous delivery system for lutein (an antioxidant carotenoid with vision-supportive and hepatoprotective properties) as a PN additive. Methods: An albumin–lutein nanosuspension (AlbLuteN) was synthesized using a modified nanoparticle albumin-bound (nab^TM) technology and characterized physicochemically. The nanoformulation was added to four commercial PN admixtures to assess the supplementation safety throughout the maximum infusion period. Visual inspection and measurements of fat globules larger than 5 µm (PFAT5) and the mean hydrodynamic diameter (Z-average), zeta potential, pH, osmolality, and lutein content were performed to detect potential interactions and evaluate the physicochemical stability. Results: AlbLuteN consisted of uniform particles (Z-average of 133.5 ± 2.8 nm) with a zeta potential of −28.1 ± 1.8 mV, lutein content of 4.76 ± 0.39%, and entrapment efficiency of 84.4 ± 6.3%. Differential scanning calorimetry confirmed the amorphous state of lutein in the nanosuspension. AlbLuteN was successfully incorporated into PN admixtures, without visible phase separation or significant changes in physicochemical parameters. The PFAT5 and Z-average values remained within pharmacopeial limits over 24 h. No substantial shifts in zeta potential, pH, or osmolality were observed. The lutein content remained stable, with losses below 3%. Conclusions: AlbLuteN can be safely added to representative PN admixtures without compromising their stability. This approach offers a novel strategy for intravenous lutein delivery and may contribute to improving the nutritional profile of PN. Full article

This study presents the synthesis, characterization, and application of magnetic magnetite–zirconium dioxide (Fe₃O₄–ZrO₂) nanoparticles as an efficient nanoadsorbent for fluoride removal from water. The nanoparticles were synthesized using a wet chemical co-precipitation method with Fe/Zr molar ratios of 1:1, 1:2, and 1:4, and characterized using Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS). FTIR analysis confirmed the presence of Fe₃O₄ and ZrO₂ functional groups, while XRD showed that increased Zr content led to a dominant amorphous phase. SEM and EDS analyses revealed quasi-spherical and elongated morphologies with uniform elemental distribution, maintaining the designed Fe/Zr ratios. Preliminary adsorption tests identified the Fe/Zr = 1:1 (M1) nanoadsorbent as the most effective due to its high surface homogeneity and optimal fluoride-binding characteristics. Adsorption experiments demonstrated that the material achieved a maximum fluoride adsorption capacity of 70.4 mg/g at pH 3, with the adsorption process best fitting the Temkin isotherm model (R² = 0.987), suggesting strong adsorbate–adsorbent interactions. pH-dependent studies confirmed that adsorption efficiency decreased at higher pH values due to electrostatic repulsion and competition with hydroxyl ions. Competitive ion experiments revealed that common anions such as nitrate, chloride, and sulfate had negligible effects on fluoride adsorption, whereas bicarbonate, carbonate, and phosphate reduced removal efficiency due to their strong interactions with active adsorption sites. The Fe₃O₄–ZrO₂ nanoadsorbent exhibited excellent magnetic properties, facilitating rapid and efficient separation using an external magnetic field, making it a promising candidate for practical water treatment applications. Full article

A series of linear isocyanate-free polyurethanes (NIPUs) were obtained via the aminolysis of erythritol dicarbonate (EDC) with polyethers (diamino-PEG, diamino-PPO, and diamino-PEG/PPO) and 1,12-diaminododecane (DADD), which acts as a chain extender to form hard segments. The obtained NIPUs contained different concentrations of DADD relative to the polyether (72.5–80 wt%). A detailed chemical structure analysis of the synthesized NIPU was performed using a combination of FTIR and ¹H NMR. FTIR spectra confirmed that the EDC/DADD segments formed a network of hydrogen bonds. This is reflected in WAXD diffractograms showing ordered crystalline domains originating in DADD. The reflections assigned to the EDC/DADD segments exhibited changes in their position and intensity with decreasing concentration, indicating an increase in interplanar spacing and a loss of higher-order order. WAXD also showed that the soft segments of PEG and PEG/PPO retain their ordered crystal structure regardless of the EDC/DADD content. At a larger length scale, SAXS revealed similar micromorphology for the different polyethers, with a broad peak indicating long-range order in the EDC/DADD-rich segments and a weak separation of the soft and hard phases. DSC analyses confirmed the complex phase behavior, where the PEG-based materials showed melting of crystalline fragments, and the amorphous PPO showed a glass transition. DMA indicated the stability of the glass transition temperature in the PPO samples and the presence of an unusual structural transition. The results emphasize the influence of the type of poly(ether) on the thermal and microphase properties of the studied non-isocyanate polyurethanes. Full article

The inherent brittleness and limited toughness of bulk metallic glasses (BMGs) remain critical challenges for their application as structural engineering materials. In this study, ultrasonic excitation was applied to Zr_58.75Cu_21.15Fe_4.7Al_9.4Nb₆ BMG with the aim of enhancing its mechanical performance. The results reveal that ultrasonic treatment significantly increases the fracture toughness by approximately 28% and induces a pronounced plastic deformation plateau following yielding. This improvement in both strength and ductility is attributed to the formation of nanoscale crystalline phases and ultrasound-induced phase separation within the amorphous matrix, which collectively promote shear band multiplication and inhibit crack propagation. Full article

This study investigated the chemical, thermal, and mechanical properties of segmented polyurethanes (SPUs) synthesized using less common biodegradable polyester polyols, specifically poly(adipate) (PAD) and poly(sebacate) (PSC), to evaluate their potential as nerve guidance conduits (NGCs) in peripheral nerve regeneration. The synthesis of novel 4,4′ methylene-bis-cyclohexyl diisocyanate (HMDI) SPUs was conducted in a two-step process: prepolymer formation and chain extension with 1,4-butanediol (BO) or 1,4-butanediamine (BA). SPUs were synthesized with two molar ratios—polyol:HMDI:BA/BO at 1:2:1 and 1:3:2 for the PAD:HMDI:BA system—to optimize mechanical properties. 1HRMN analysis verified the expected chemical structure of SPUs, whereas Raman and IR spectroscopy confirmed successful polyurethane synthesis. X-ray diffractograms showed that PAD-based SPUs (SPUPAD) were amorphous while PSC-based SPUs (SPUPSC) exhibited semi-crystalline behavior. SPUPAD showed only one degradation stage by TGA, while DSC showed one thermal event. In contrast, SPUPSC exhibited two degradation stages and three thermal events that confirmed phase separation. The longitudinal tensile properties of an NGC fabricated from SPUA-PAD-2 (PAD:HMDI:BA (1:3:2)) after 30 days of immersion in water (25 °C) showed a lower modulus (4.46 ± 0.5 MPa) than native intact nerves (15.87 ± 2.21 MPa) but a similar modulus to extracted nerves (8.19 ± 7.27 MPa). This system exhibited a longitudinal tensile force of 11.1 ± 1.6 N, which is lower than that of peripheral nerves (19.85 ± 7.21 N) but higher than that of commercial collagen-based nerve guide conduits (6.89 ± 2.6 N). The observed properties suggest that PUA-PAD-2 has potential as a biomaterial for nerve regeneration applications. Full article

A TC4 alloy was joined with Ti-Zr-Cu-Ni amorphous filler by vacuum brazing. The paper further explored how different brazing temperatures with a 20 min holding time, or varying holding times at a brazing temperature of 900 °C, impact the interface width, microstructure, composition distribution, microhardness, shear strength, and fracture surface of the brazed joints. The findings indicated that as the brazing temperature increased, the interface width became wider. Moreover, as the brazing temperature continued to rise, both the size of the Widmanstätten structure and the amount of the (Ti, Zr)₂(Cu, Ni) brittle phase increased continuously, leading to the joint exhibiting harder and more brittle properties. As the temperature rose from 860 °C to 900 °C, the microhardness went up from 462.8 HV_0.1 to 482.6 HV_0.1. But when the temperature continued to increase (920 °C, 940 °C), the microhardness started to decrease, until it reached 392.6 HV_0.1 at a holding time of 20 min. As the brazing temperature increased, the width of the joint interface expanded, and the shear strength continued to rise. When the brazing temperature rose to 940 °C, the shear strength increased to 223.9 MPa under a holding time of 20 min. With the prolongation of the holding time (from 10 min to 30 min), the Widmanstätten structure at the joint interface continuously grew towards the center. Additionally, the (Ti, Zr)₂(Cu, Ni) phase and eutectic structure were separated by the Widmanstätten structure. The microhardness and shear strength reached their maximum values at 900 °C, and the shear strength was measured at 137.6 MPa. Full article

Microporous alumophosphate molecular sieves AlPO₄-n are promising materials for use in catalysis, gas adsorption, and gas separation. However, AlPO₄-n faces problems such as diffusion limitations that lead to a deterioration in mass transfer. To solve this problem, we studied the crystallization of alumophosphate reaction gels prepared using aluminum isopropoxide and various secondary amines as templates, including diethyl-, di-n-propyl-, diisopropyl-, and di-n-butylamines. Using X-ray diffraction, Ramon spectroscopy, and STEM methods, it has been demonstrated that the reaction gels prepared using DPA, DIPA, and DBA are amorphous xerogels consisting of 5–10 nm nanoparticles. The reaction gel prepared with DEA is a combination of a layered phase and an amorphous aluminophosphate. It has been shown that the use of aluminum iso-propoxide allows the production of AlPO₄-11 in the form of 2–4 µm aggregates consisting of primary AlPO₄-11 nanocrystals. The template was found to exert a significant effect upon both the characteristics of the porous structure and the size of AlPO-11 nanocrystals. A template is proposed for the synthesis of hierarchical AlPO₄-11 with a maximum volume of mesopores. The morphology and crystal size of AlPO₄-11 were found to strongly influence its adsorption properties in the adsorption of octane. Full article

This study investigates enhancing polylactic acid (PLA) by incorporating recycled polycarbonate (r-PC) to address PLA’s inherent brittleness and limited thermal stability. Blends with varying PLA/r-PC ratios (100:0 to 0:100) were prepared using an internal mixer, with r-PC sourced from discarded compact discs. The thermogravimetric analysis (-A) demonstrated significant improvements in the thermal stability. The degradation onset temperature (T₅ wt%) increased from approximately 315 °C for pure PLA to about 400 °C in the blends, with a maximum decomposition temperature (T_max) of 520 °C observed for pure r-PC. The char residue also increased markedly, from 1.35% in pure PLA to 24.42% in r-PC, indicating enhanced thermal resistance. Differential scanning calorimetry (DSC) revealed a considerable reduction in PLA crystallinity, declining from 68.17% in pure PLA to 10.32% in the 10PLA90r-PC blend, indicative of the disruption of PLA’s crystalline structure. The X-ray diffraction (XRD) analysis supported these findings, showing a transition to a predominantly amorphous structure at higher r-PC contents. Tensile testing highlighted the mechanical improvements achieved through blending. While pure PLA exhibited brittle failure, the 30PLA70r-PC blend displayed plastic deformation, signifying improved toughness. The stress–strain analysis revealed that the 30PLA70r-PC blend achieved a peak toughness of 8725 kJ/m³, nearly ten times higher than the 924 kJ/m³ recorded for pure PLA. However, excessive r-PC content introduced brittleness, diminishing toughness. The dynamic mechanical thermal analysis (DMTA) demonstrated a broadening of the glass transition range, with the T_g shifting from 61 °C for pure PLA to 141 °C in r-PC-dominant blends, reflecting improved phase interactions between the two polymers. Scanning electron microscopy (SEM) revealed significant morphological changes; at high r-PC contents, phase separation and voids were observed, leading to reduced mechanical performance. These results highlight the synergistic potential of blending PLA’s biodegradability with r-PC’s superior thermal and mechanical properties. Full article

Amorphous solid dispersion (ASD) is one of the most important enabling formulation technologies for the development of poorly soluble drugs. Because of its thermodynamically unstable nature in both solid and wet states, the evaluation and optimization of the formulation performance involves some difficulties. The dissolution process is sensitively influenced by various factors, including the applied dose, medium composition, and pH. Supersaturated solutions can cause liquid–liquid phase separation (LLPS) and/or crystallization, which complicates the comprehension of the dissolution process. However, LLPS should be evaluated carefully because it is closely related to oral absorption. As LLPS concentration is analogous to amorphous solubility, it can be a key factor in predicting oral absorption from ASDs, if absorption is limited by solubility. Moreover, LLPS droplets are expected to increase transmembrane flux by increasing the drug concentration near the epithelial cell membrane. In this review, recently updated knowledge on the dissolution, membrane permeation, and oral absorption behaviors of ASDs is discussed with an emphasis on LLPS behavior. Full article

In this paper, the crystallization behavior of 52WO₃:22B₂O₃:26La₂O₃:0.5Eu₂O₃ glass has been investigated in detail by XRD and TEM analysis. The luminescent properties of the resulting glass-ceramics were also investigated. By XRD and TEM analysis, crystallization of β-La₂W₂O₉ and La₂WO₆ crystalline phases has been proved. Photoluminescent spectra showed increased emission in the resulting glass-ceramic samples compared to the parent glass sample due to higher asymmetry of Eu³⁺ ions in the obtained crystalline phases, where the active Eu³⁺ ions are incorporated. Also, in the glass-ceramics, the crystalline particles are embedded in the amorphous matrix and more of them are separated from each other which improves the light scattering intensity from the free interfaces of the nanocrystallites, resulting in the enhancement of the PL intensity. It was established that the optimum emission intensity is registered for glass-ceramic samples obtained after an 18 h heat treatment of the parent glass. After 21 h of glass crystallization, the amount of crystallite particles is high enough, and they are in close proximity to each other, and hence, the average distance between europium ions decreases, resulting in quenching of Eu³⁺ and a decrease in the emission intensity. Additionally, at 21 h of glass crystallization, formation of new crystalline phase—La₂WO₆ is established. A redistribution of Eu³⁺ ions in the different crystalline compounds is most likely taking place, which is also not favorable for the emission intensity. Full article