Search Results (165)

The rising prevalence of chronic kidney disease (CKD) has intensified the demand for innovative blood filtration therapies. Hemoperfusion, which integrates membrane filtration with adsorbent technologies to sequester circulating uremic toxins, represents a promising therapeutic alternative. In this study, polyethersulfone (PES)-powdered activated carbon (PAC) composite membranes were fabricated via nonsolvent-induced phase separation (NIPS), and the molecular weight of polyethylene glycol (PEG) was optimized as a hydrophilic pore-forming agent. Dope solutions were formulated with 15 wt.% PES, 1 wt.% PAC, and 10 wt.% PEG at varying molecular weights (200, 400, 600, and 1000 Da). Comprehensive characterization revealed that PEG molecular weight significantly dictates the structural and functional performance of the resulting composites. The PEG 600 Da variant achieved an optimal balance of properties, characterized by homogeneous PAC dispersion, a peak water flux of 420.88 LMH/Bar, a water contact angle of 37.11°, and a porosity of 74.74%, while maintaining a high Bovine Serum Albumin (BSA) rejection of 90.87%. While increasing PEG molecular weight generally enhanced permeability through the formation of an open pore architecture, a performance trade-off was observed beyond the 600 Da threshold due to increased dope viscosity and altered phase inversion kinetics. These findings suggest that PEG 600-optimized PES-PAC membranes offer a high-performance, affordable platform for advanced hemoperfusion applications. Full article

Direct air capture (DAC) requires carbon capture interfaces that operate under highly dilute CO₂ conditions while minimizing thermal and chemical regeneration penalties. Carbonic anhydrase (CA) accelerates the reversible hydration of CO₂ to bicarbonate and is therefore a strong biocatalytic candidate for low-temperature CO₂ capture, but its implementation depends on candidate support materials that combine wet-state accessibility, chemical reactivity, mechanical processability and compatibility with membrane architectures. This study reports the preparation and screening of N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS)-reactive biopolymer composite membranes for future carbonic anhydrase (CA) immobilization. Chitosan particles were precipitated with citrate or tripolyphosphate under high-shear homogenization and compared after lyophilization or convective drying. Chitosan-, shellac-, agarose- and cellulose-acetate-based films plasticized with glycerol and/or polyethylene glycol 400 (PEG-400) were then evaluated by optical microscopy, dry-state penetrometric puncture testing, qualitative EDC/NHS-reactivity mapping and Fourier-transform infrared spectroscopy (FTIR). Freshly precipitated chitosan particles showed dendrite-like high-surface morphologies, while lyophilization preserved porous flocculated aggregates and convective drying produced denser collapsed structures. Neat chitosan showed the highest dry-state puncture force (2.230 ± 0.173 N), whereas chitosan/shellac (0.377 ± 0.044 N) and agarose/chitosan/PEG-400 (0.386 ± 0.038 N) provided the strongest reactive-composite compromise between dry-state puncture resistance and EDC/NHS compatibility. The EDC/NHS reactivity map identified chitosan- and shellac-containing films as the chemically most relevant supports because they provide amine and/or carboxyl functionality, whereas agarose and cellulose acetate alone were not directly suitable for zero-length amidation. FTIR spectra confirmed polymer-specific functional signatures and EDC/NHS-associated changes in carbonyl, amide and C-O/C-O-C regions, especially in shellac- and chitosan-containing composites. The results identify chitosan/shellac as the lead candidate membrane and agarose/chitosan/PEG-400 as a hydration-rich comparator for subsequent carbonic anhydrase immobilization studies. This work should be interpreted as a first-stage materials-screening study of candidate membranes for enzyme immobilization. Full article

Composite hydrogel based on acrylic acid and acrylamide, modified with metal ions (Ni²⁺, Al³⁺, Fe²⁺, Fe³⁺) with concentration 0.3 wt%, were synthesized in water or polyethylene glycol (with a molecular weight of 400 Da) at three monomer ratios (7/3, 1/1, 3/7). Dynamic mechanical analysis shows that the equilibrium modulus of elasticity ($G_e$) of unmodified hydrogels increases with acrylamide content due to higher crosslinking density ($n_e$) and smaller cell size. ${AlCl}_3$ or ${NiCl}_2$ strengthen the structure ($G_e$ increases +53.5% in a 1/1 ratio), while iron salts cause softening (decreases to 90% when using ${FeC}_2{O}_4$). Partial replacement of polyethylene glycol reduces the elasticity but when using ${AlCl}_3$ happens synergistic increase $n_e$ 1.9 times in the ratio 3/7. The self-healing efficiency reaches ~100% for ${FeCl}_3$ in PEG gel in a ratio of 1/1 and 72.1% for ${Fe\left({NH}_4\right)}_2{\left({SO}_4\right)}_2$ hydrogel in 3/7. The electrical conductivity of hydrogels increases in the range of ${Al}^{3+}>{Ni}^{2+}>{Fe}^{3+}$, while matrix based on polyethylene glycol reduces the conductivity by an order of magnitude. For ${Ni}^{2+}$-containing samples, pinched hysteresis loops are observed in both water and polyethylene glycol. In contrast, ${Al}^{3+}$ causes rapid passivation in the water matrix, while in the matrix based on polyethylene glycol, the current–voltage characteristics follow ohmic behavior. The results demonstrate the possibility of directional regulation of the mechanical, electrical, and self-healing efficiency of hydrogels by selecting the ratio of monomers, the nature of the ion modifier, and the type of solvent. Full article

Background: Iodine-based antimicrobial systems remain highly attractive due to their broad-spectrum activity; however, the clinical application of free iodine is limited by its instability and cytotoxicity. This study aimed to develop polyethylene glycol (PEG)-based hydrophilic ointment formulations containing a dextrin/polyvinyl alcohol/iodine complex (D/PVA/I) and to evaluate their physicochemical properties, antimicrobial activity, and cytotoxicity. Methods: Hydrophilic ointment formulations containing 2.5%, 5.0%, and 10.0% D/PVA/I were prepared using a PEG-based matrix composed of PEG 4000, PEG 400, and glycerol. Physicochemical characterization included organoleptic evaluation, pH measurement, rheological analysis, and UV–visible (Ultraviolet–visible) spectroscopy. Antimicrobial activity was assessed using agar diffusion and minimum bactericidal concentration (MBC) assays against Staphylococcus aureus, Escherichia coli, Enterococcus hirae, and Pseudomonas aeruginosa. Cytotoxicity was evaluated in Madin–Darby Canine Kidney (MDCK) cells using the MTT assay. Results: All formulations exhibited homogeneous semisolid structure and physiologically acceptable pH values (4.94–5.45). Rheological analysis demonstrated non-Newtonian pseudoplastic (shear-thinning) behavior. The flow behavior index (n) ranged from 0.03 to 0.33 according to the Ostwald–de Waele model, confirming shear-thinning characteristics, while viscosity increased with increasing D/PVA/I concentration. UV–visible spectroscopy confirmed the presence of triiodide ions (I_3⁻), characterized by absorption maxima at approximately 287 and 350 nm, indicating preservation of active iodine species within the PEG matrix, while placebo (blank) formulation analysis confirmed the absence of corresponding absorption bands, demonstrating that the PEG-based matrix does not contribute to the characteristic spectral features. The formulations demonstrated broad-spectrum antimicrobial activity, with MBC values ranging from 0.01 to 0.02 µg/mL. Cytotoxicity studies revealed moderate toxicity of the D/PVA/I complex (CC₅₀ = 0.82%) (50% cytotoxic concentration (CC₅₀) and significantly lower toxicity of the PEG-based ointment base (CC₅₀ = 18.38%). Conclusions: The developed PEG-based hydrophilic ointment formulations containing the D/PVA/I complex demonstrated favorable physicochemical characteristics, stability of iodine species, pronounced antimicrobial activity, and acceptable cytotoxicity profiles. These findings highlight the potential for the developed systems to be promising topical antimicrobial formulations. Full article

The cornea and conjunctiva are particularly susceptible to injury and adverse effects, either induced by topically applied drugs or excipients used in ophthalmic formulations. Surfactants and cosurfactants are important for producing topical eye formulations of poorly water-soluble drugs, yet they have not been always used in concentrations that are nontoxic and non-irritating to the ocular surface. This study systematically compared the cytotoxicity and ocular irritation potential of commonly used ophthalmic surfactants and cosurfactants under standardized experimental conditions using complementary in vitro and ex vivo ocular safety models. The ocular irritation of Tween 80, Cremophor EL, polyethylene glycol 400 (PEG 400) and propylene glycol (PG) was examined using the HET-CAM (conjunctival) and BCOP (corneal) eye assays. The toxic effect of the four excipients after 24 h on HLE-B3 cell growth was investigated and found to be dose-dependent. The highest tolerable concentrations of Tween 80 and Cremophor EL were 0.25% (w/w), whereas PEG 400 and PG were non-toxic at 5% (w/w). Tween 80 and Cremophor EL at 0.25% (w/w) and PEG 400 and PG at 5% (w/w) were all devoid of conjunctival and corneal irritation. This study systematically compared the cytotoxicity and ocular irritation potential of commonly used ophthalmic surfactants and cosurfactants under standardized experimental conditions using complementary in vitro and ex vivo ocular safety models. Interestingly, there is strong agreement between the results obtained using the HET-CAM and BCOP assays, where both have been successfully used to evaluate the potential for ocular irritation caused by the aforementioned excipients. Full article

Background: Hot-melt extrusion (HME) is a promising technology for the manufacturing of drug products; however, its application is limited by elevated thermal and shear stresses that may induce degradation of thermolabile active pharmaceutical ingredients. One of the approaches to reducing processing temperatures is the use of polymeric systems with tailored thermal and rheological properties. The aim of the study was to develop an approach for the design of polymeric systems exhibiting a transient plasticization window, enabling a reduction in melt viscosity and improved processability under low-temperature extrusion conditions, followed by the formation of a structurally coherent matrix upon cooling. Methods: The compatibility of the initial polymers was assessed using laser microinterferometry. Based on the obtained data, three- and four-component polymeric compositions were designed and prepared by hot-melt extrusion. The resulting materials were characterized by differential scanning calorimetry, melt rheology analysis, and storage stability assessment. Thermal and rheological data were used to iteratively optimize the polymeric systems. Results: A four-component polymeric system based on PVP K-29/32, PEG 400, PEG 1500, and HPC EF was developed, suitable for processing by hot-melt extrusion at 70 °C. The final system enabled formation of a homogeneous extrudate, exhibited reproducible rheological behavior, and remained stable in the solid-state during storage, with no evidence of cold flow. Conclusions: It was established that, in the design of polymeric systems for hot-melt extrusion, the key factor is not achieving the lowest possible glass transition temperature, but rather the design of a system in which viscosity is transiently reduced under processing conditions and followed by structural stabilization upon cooling. The proposed approach may be applied in the development of polymeric premixes for the preparation of dosage forms by hot-melt extrusion, including those incorporating thermolabile active pharmaceutical ingredients. Full article

In this current study, beech wood (Fagus sylvatica) was modified by cross-linking via esterification with combinations of polyethylene glycol (PEG) 400 and various carboxylic acids. Promising combinations (1,2,3,4-butanetetracarboxylic acid (BTCA)/PEG400; citric acid (CA)/PEG400; malic acid (MA)/PEG400) were examined in previous studies. The goal of this study was the optimisation of the treatment. The use of a catalyst, the concentration of the chemicals and the curing conditions were varied. The weight percentage gain (WPG), bulking and anti-swelling efficiency (ASE) after leaching in water were used to evaluate the success of modification. Optimal results were achieved with a curing temperature of 160 °C. Without the addition of PEG, the WPG and bulking values were lower. The use of sodium hypophosphite monohydrate (SHP) as a catalyst had a positive effect only on the combination of BTCA/PEG400. Variations of concentrations usually had a higher impact on WPG and bulking than on ASE. The combination of MA/PEG 400 generally showed lower values. Full article

Background/Objectives: Poor aqueous solubility limits the oral absorption and bioavailability of many active pharmaceutical ingredients. Simple formulation approaches suitable for hospital and community pharmacy compounding are therefore needed. This study aimed to develop and evaluate melt-filled hard capsules containing nifedipine, a model of poorly water-soluble BCS class II drug, using polyethylene glycol (PEG) carriers to improve dissolution performance. Methods: PEG blends of different molecular weights (PEG 400, PEG 1500, and PEG 4000) were prepared by melt mixing, followed by incorporation of nifedipine and manual filling into hard gelatin capsules. The formulations were characterized regarding mass variation, drug content, in vitro dissolution, rheological behavior, and solid-state properties using Fourier transform infrared (FTIR) spectroscopy. Dissolution profiles were kinetically modeled and compared with pure nifedipine. Results: All capsules met pharmacopoeial requirements for mass uniformity and showed acceptable drug content. PEG-based melt-filled formulations exhibited markedly enhanced dissolution compared with crystalline nifedipine. Faster drug release was associated with lower-molecular-weight PEGs and reduced viscosity, with the PEG 400/PEG 1500 blend demonstrating the most rapid dissolution. Rheological analysis confirmed shear-thinning behavior, while FTIR findings suggested intermolecular interactions and partial amorphization of nifedipine within the PEG matrices. Conclusions: This study provides a translational adaptation of solid dispersion principles into a compounding-compatible melt-filling approach. Full article

Cellulose ether, like hypromellose (HM), is an extremely versatile material that is widely used in pharmaceutical products as film coatings. To modify the surface properties of HM films, additives are routinely included during the film formulation process, which are typically hydrophobic lubricants or hydrophilic plasticizers. Plasticizers increase the flexibility and reduce the brittleness of the film. The first goal of this study is to demonstrate that plasticization of HM films by low-molecular-weight (400 g∙mol⁻¹) polyethylene glycol (PEG) allows tuning adhesion and friction properties of HM films, both at nano- and macroscales. Surface morphology, surface energy, nano/macro adhesion, and nano/macro friction coefficient were studied by atomic force microscopy (AFM) in adhesion or friction modes at the nanoscale, wettability, and probe-tack adhesion, as well as pin-on-disk friction experiments at the macroscale. The results show that the addition of PEG decreases the Young’s modulus and the Tg of HM-plasticized films while increasing their strain at break and surface energy. The macroadhesion force increases from 9 to 90 mN by the addition of 40% w/w of PEG, whereas the macrofriction coefficient is reduced by 50%. The hypothesis of insertion of plasticizer molecules in HM chains’ nano-domains is evidenced and explains these results. The second goal of this study is to investigate nanoscale versus macroscale correlation of adhesion and friction properties and the role of adhesion in friction experiments. The results show, first, that the evolution of the adhesion energy at the macroscale as a function of adhesion energy at the nanoscale is linear. On the contrary, a high friction coefficient at the nanoscale corresponds to a low friction coefficient at the macroscale and vice versa, showing a first linear decrease for PEG contents ranging from 0 to 30% (w/w) and the second linear decrease, less pronounced, is observed for PEG contents ranging from 30 to 40% (w/w). The hypothesis of a difference in contact pressure applied on the probe at both scales, as well as HM-PEG surface phase separation at a high PEG content (>30% w/w), is proposed to explain this difference. The variations in friction coefficients are linear according to the PEG plasticizer content and suggest its lubricant role in HM-Plasticized films. Finally, the interplay between adhesion and friction, in friction experiments, is evidenced and appears dominant at the nanoscale. Full article

To reduce food waste and mitigate health risks from accidentally consuming spoiled food, freshness-indicating technologies are increasingly demanded. However, conventional colorimetric-based freshness-indicating packaging is limited by instability, subtle color changes, and complex production processes. This study presents a curcumin-based ink suitable for eco-friendly polylactic acid (PLA) food packaging films enabling real-time shrimp freshness monitoring via integrated intelligent packaging. The ink comprised curcumin as the indicator, ethyl cellulose (EC) and polyvinyl butyral (PVB) as binders, and polyethylene glycol 400 (PEG 400) to regulate permeability. Excellent printability was demonstrated by fineness, initial dryness and fluidity tests. It also demonstrated good thixotropic, viscosity, and flow curve properties. Printing minimally affected the PLA films’ mechanical and barrier properties. The indicator label showed high sensitivity, rapid response, and excellent reversibility to ammonia vapor. Practical application in monitoring shrimp spoilage at 25 °C and 4 °C revealed a strong correlation between the distinct color transition of the label and the increase in total volatile basic nitrogen (TVB-N) content and pH value, providing a reliable visual warning before obvious spoilage signs appeared. This work provides a viable integrated indicator packaging strategy for developing intelligent packaging, offering significant potential to reduce food waste and enhance supply chain transparency for perishable goods. Full article

This study presents a numerical investigation of the laminar forced convection of polyethylene glycol-based nanocolloids within a horizontal pipe. To bridge the gap between theoretical predictions and practical performance, simulations were conducted over a Reynolds number range of 500 to 2000, utilizing a model validated against laboratory-scale experimental data and well-defined boundary conditions. Our analysis focuses on the thermal behavior of polyethylene glycol 200 enriched with metal oxide nanoparticles and multi-walled carbon nanotubes, which were selected for their capacity to enhance thermal conductivity while maintaining manageable viscosity. The results demonstrate that PEG 200-based nanocolloids significantly improve heat transfer performance in the laminar regime. This enhancement is attributed to the superior intrinsic thermal properties of the nanoparticles and the complex synergistic interactions—such as Brownian motion and thermophoresis—between the particles and the PEG base fluid. A critical evaluation of the standard approach of incorporating thermophysical properties into the numerical approach led to significant discrepancies in flow predictions. Additionally, our study establishes that assuming constant thermophysical properties during the heating process introduces simulation errors exceeding 10%. These findings underscore the necessity of incorporating temperature-dependent, experimentally validated data into numerical models to ensure predictive accuracy. Ultimately, this work advocates for a nuanced approach to nanocolloid design that prioritizes the specific chemical and rheological compatibility between nanoparticle types and the base fluid. Full article

This study aimed to evaluate the impact of liquid–solid (LS) systems on the dissolution profiles of a poorly soluble drug—suvorexant (SUV). In the first stage of this study, LS systems were prepared by using two different non-volatile solvents: ethylene glycol diethyl ether and polyethylene glycol 400 (PEG 400). To compare the properties of different types of LS systems, formulations were prepared that differed in the content of SUV (10 and 20 mg) as well as in the ratio of excipients (microcrystalline cellulose and colloidal silica), which was 10:1 or 1:1. The physicochemical properties of the prepared formulations were characterized by X-ray diffractometry (XRD), thermogravimetry (TGA) and differential scanning calorimetry (DSC). This was followed by a dissolution study of SUV from prepared LS systems, using a 0.4% sodium lauryl sulfate solution as the medium to maintain sink conditions. Results showed that the LS systems change the crystalline structure of SUV to an amorphous one and improve the dissolution rate of SUV. The greatest improvement was achieved by using the microcrystalline cellulose and colloidal silica in a 10:1 ratio for the preparation of the system (CCA variant). It was observed that the type of solvent used and the order of combining excipients during the preparation of LS systems are also important for the properties. The main point was that physicochemical characterization of the prepared formulations lead to a loss of crystallinity of SUV associated with its introduction into liquid–solid systems. Full article

Thermoplastic polyurethane properties are governed by the interplay between soft-segment mobility, hard-segment interactions, and segmented morphology, yet the extent to which atomistic predictions of their thermal and mechanical behavior depend on force-field choice remains insufficiently benchmarked. Here, we combine FTIR, DSC, TGA, and tensile testing with all-atom molecular dynamics simulations to investigate HDI–PEG polyurethane systems across a controlled soft-segment series. Experimentally, films with PEG molecular weights of 400, 1000, and 1500 g/mol were characterized, while simulations were extended to 400–2000 g/mol to compare two complementary force-field frameworks under a consistent protocol: OPLS-AA, a conventional atom-type-based force field, and OpenFF/Sage, a direct-chemical-perception framework augmented here with bespoke torsional refinements. Both force fields reproduce the composition-driven decrease in Tg and density with increasing PEG length, but differ systematically in absolute values, with OPLS-AA predicting higher densities and Tg values than OpenFF. Tensile experiments show the highest elastic modulus for PEG400, a marked decrease at PEG1000, and a partial recovery at PEG1500. Although nanosecond-scale deformation simulations overestimate absolute moduli because they probe high-rate elastic response, they recover composition-dependent stiffness differences, with OpenFF yielding a more pronounced non-monotonic trend than OPLS-AA. Overall, this work provides an experimentally anchored benchmark for assessing which composition-driven trends in HDI–PEG polyurethanes are robust across force-field families, and which observables remain sensitive to model assumptions and simulation scale. Full article

Polyethylene glycols (PEGs) are emerging as superior and accessible phase change materials and heat transfer fluids, offering improved thermal properties over conventional thermal oils to meet the demand for innovative, sustainable energy solutions. While general research on PEG performance is still scarce, this paper contributes relevant experimental data. As part of a broad investigation into PEG and PEG-based nanocolloids, this experiment helps to clarify the true potential of these new fluids by outlining both their key advantages and their operational limitations. Consequently, PEG 200 and two PEG 200 + PEG 400 mixtures were considered as base fluids for manufacturing MWCNT nanocolloids, resulting in 15 samples that were thoroughly investigated in terms of density, viscosity and isobaric heat capacity variation with both nanoparticle concentration and temperature. Results revealed that nanocolloid density follows the basic rules for nanoparticle-enhanced fluids, with moderate increase with nanoparticle addition and temperature. Viscosity increased with MWCNT concentration and decreased with temperature, while isobaric heat capacity upsurges with nanoparticle addition. These findings are critical, as they can shed some light into the practical benefits, while clearly explaining the potential drawbacks, of employing these novel fluids in heat transfer applications. Full article

Colletotrichum fructicola is the predominant pathogenic agent responsible for anthracnose in Camellia oleifera. RGS2 is a GTPase-activating protein that negatively regulates G-protein signaling by inactivating Gα subunits. In this study, we characterized the ortholog of CfRGS2 in C. fructicola to explore its pathogenic roles. Seven canonical RGS genes were identified through BLASTp and keyword searches. Conserved domains and subcellular localizations were predicted bioinformatically. A CfRGS2 knockout mutant was generated via overlap-PCR and PEG-mediated transformation, verified by PCR, and complemented by reintroducing the wild-type gene. Phenotypic characterization showed that the growth rates of mutants ΔCfrgs2-1 and ΔCfrgs2-2 were significantly reduced compared with those of the wild-type and complemented strains. On both PDA and minimal medium, the mutant strains exhibited significantly smaller colony diameters of 3.3 cm and 3.1 cm, respectively, relative to the control strains. Moreover, conidiation in the mutants was only 4% of that in the wild-type and complemented strains, and appressorium formation was reduced to 6%, with statistical analyses confirming high significance. Under cell wall stress induced by 400 μg/mL Congo red, the growth inhibition rates of ΔCfrgs2-1 and ΔCfrgs2-2 were 44% and 48%, respectively, significantly higher than those of the control strains. Pathogenicity assays demonstrated that the mutants failed to induce lesions on unwounded leaves and caused 47% and 30% smaller lesion areas on wounded apple fruits, respectively. In summary, C. fructicola possesses seven canonical RGS proteins that regulate G-protein signaling, among which CfRgs2 is implicated in growth, conidiation, the stress response to cell wall perturbation, and virulence. Full article