Mixture Of Polyethylene Glycol Research Articles

Effects of intramolecular chain conformation on the hydration and miscibility of polyethylene glycol in water studied by means of polymer reference interaction site model theory.

To examine the conventional idea that the gauche conformation of the OCCO dihedral angle promotes the dissolution of polyethylene glycol (PEG) in water through strong hydration, the thermodynamic properties of liquid mixtures of PEG and water were studied by means of polymer reference interaction site model (PRISM) theory. The intramolecular correlation functions required as input for PRISM theory were calculated by the generator matrix method, accompanied by changes in the distribution of dihedral angles. In the infinite dilution limit, the increased probability of gauche conformation of the OCCO dihedral angles stabilizes the hydration of PEG through enhanced hydrogen bonding between the ether oxygen of PEG and water. The mixing Gibbs energies of the liquid mixtures were also calculated in the whole concentration range based on the Gibbs-Duhem equation, as per our recent proposal. A liquid-liquid phase separation was observed when all the dihedral angles of PEG were in the trans conformation; for the liquid mixture to be miscible in the whole concentration range, the introduction of the OCCO gauche conformation was found to be indispensable. The above theoretical results support the conventional idea that the OCCO gauche conformation is important for the high miscibility of PEG and water.

In vivo skin optical clearing efficacy quantification of clinically compatible agents using line-field confocal optical coherence tomography.

The clinical use of optical methods for in vivo skin imaging is limited by skin strong scattering properties, which reduce image contrast and probing depth. The efficiency of optical methods can be improved by optical clearing (OC). However, for the use of OC agents (OCAs) in a clinical setting, compliance with acceptable non-toxic concentrations is required. OC of in vivo human skin, combined with physical and chemical methods to enhance skin permeability to OCAs, was performed to determine the clearing-effectiveness of biocompatible OCAs using line-field confocal optical coherence tomography (LC-OCT) imaging. Nine types of OCAs mixtures were used in association with dermabrasion and sonophoresis for OC protocol on three volunteers hand skin. From 3D images obtained every 5min for 40min, the intensity and contrast parameters were extracted to assess their changes during the clearing process and evaluate each OCAs mixture's clearing efficacy. The LC-OCT images average intensity and contrast increased over the entire skin depth with all OCAs. The best image contrast and intensity improvement was observed using the polyethylene glycol, oleic acid, and propylene glycol mixture. Complex OCAs featuring reduced component concentrations that meet drug regulation-established biocompatibility requirements were developed and proved to induce significant skin tissues clearing. By allowing deeper observations and higher contrast, such OCAs in combination with physical and chemical permeation enhancers may improve LC-OCT diagnostic efficacy.

Mechanistic Understanding on Difluoromethane Absorption Thermodynamics on Novel Deep Eutectic Solvents by COSMO-Based Molecular Simulation

Hydrofluorocarbons (HFC) are fluorinated compounds used globally for refrigeration. These gases have been shown to contain a greenhouse potential of up to 22,000 times that of CO2. Thus, 1298 type-5 deep eutectic solvents (DES) were examined for the absorption and interaction mechanisms of difluoromethane (R32), due to their non-polar attributes. Of these solvents, quaternary ammonium salts mixed with various species of hydrogen bond donators (HBD) produced the most favorable interactions, with ln activity coefficients predicted to be as low as −1.39 at 1:1 compositional ratio. These DES were further studied for compositional analysis where pure tetrabutylammonium bromide showed the strongest interaction potential. The pressure study showed a linear solubility increase with a pressure increase reaching up to 86 mol/mol% in a methyltrioctylammonium bromide and polyethylene glycol mixture at 9 bar. The van der Waals interaction is the driving force of absorption with ~3x enthalpic release over hydrogen bonding. All chemicals contain strong potential for an environmentally friendly solution, as is evident through an environmental health and safety analysis.

Formation of Aqueous Two‐Phase Systems Using Potassium Salt and Deep Eutectic Mixtures for Extraction of Proteins

AbstractLiquid‐liquid extraction such as an aqueous two‐phase system (ATPS) is considered a promising method in the biotechnology field for extraction of biomolecules. The binary mixture of polyethylene glycol (PEG)/salt is the most common ATPS. The ability of eutectic mixture‐based ATPS to fractionate protein macromolecules remains not well understood. Here, the role of hydrogen bond donors (HBDs) in eutectic mixtures was investigated in relation to the phase formation ability and extraction efficiency of protein. Both potassium salt and an eutectic combination were used to prepare the ATPSs. Choline chloride/urea aqueous two‐phase separation proved to be the most effective method for protein extraction. The creation of a two‐phase system and the efficiency with which a protein can be extracted from a crude solution are both affected by the choice of HBD.

Liquid-liquid extraction of molybdenum(VI) using aqueous two-phase systems (ATPS) consisting of polyethylene glycol (PEG) and sodium, ammonium and copper(II) salts: Comparison with conventional solvent extraction

In this work, the stripping of molybdenum from aqueous two-phase aqueous systems (ATPS) formed by a mixture of polyethylene glycol (PEG) 4000, salt and water was studied at different operational conditions of pH (7, 8 and 9) and temperature (308.15, 323.15 and 338.15 K), using two molybdenum salts (Na2MoO4 and (NH4)6Mo7O24). These salts were used for the experimental tests of extraction and stripping of the two-phase aqueous system of PEG 4000, CuSO4 and water, to evaluate the best percentage of stripping using different stripping agents: NaOH, Na2CO3, CuSO4 and a mixture of (NH4)2SO4 and NH4OH (Khayati et al., 2011). According to the results, the best stripping agent was the 20% (NH4)2SO4 solution as phase former plus 25% NH4OH as pH modifier. The experimental results indicate that the increase in temperature is directly proportional to the percentage of stripping. For the system of PEG 4000, CuSO4, water, Na2MoO4, (NH4)2SO4 and NH4OH system (ATPS 1) the percentage of stripping was 96.3%. In the case of PEG 4000, CuSO4, (NH4)6Mo7O24, water (NH4)2SO4 and NH4OH (ATPS 2) the stripping was 99%, these being the maximum values of stripping at pH = 2 and T = 308.15 K.It was determined that for ATPS 1, as the pH increases the stripping efficiency tends to decrease, while as the pH increases in ATPS 2, the stripping efficiency increases; this behavior is attributed to the hydration energy of the ions. Finally, a pre-feasibility study of the studied processes, ATPS 1, ATPS 2 and traditional solvent extraction (SX), was carried out, which included calculation of the profit factors.

Liquid nitric oxide donor for adjuvant therapy of acute ischemic stroke via nasal administration

ObjectivesThe aim of this study was to synthesize and characterize a novel NO donor, PEI-PO-NONOate, using propylene oxide and to investigate its biosafety and therapeutic efficacy via nasal administration in vitro and vivo. Experimental proceduresThe PEI-PO-NONOate was synthesized based on polyethylenimine (PEI) with different molecular weights and characterized using Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and ultraviolet (UV) spectroscopy. Cytotoxicity assays were performed on mouse fibroblast cells L929 and human nasal mucosa epithelial cells (HNEpC), and a rat middle cerebral artery occlusion (MCAO) model was established to evaluate the therapeutic efficacy of PEI-PO-NONOate via nasal administration. ResultsThe PEI-PO-NONOate was found to be stable under dark, dry, and airproof conditions, and its release was accelerated in an aqueous phase or acidic environment, while it was slowed down in a polyethylene glycol (PEG) mixture system. The NO donor released approximately 0.4, 0.5, and 0.6 μmol of gaseous NO from 1.0 mg of the polymer based on PEI600, PEI1800, and PEI10K, respectively. Cytotoxicity assays showed that the PEI-PO-NONOates had a cryoprotective effect as compared with PEI and PEI-PO. Furthermore, nasal administration of PEI-PO-NONOates resulted in a significant reduction in overall necrotic ratio as compared with the control group (16.4% versus 24.6%, p < 0.05). ConclusionThe findings of this study suggest that PEI-PO-NONOates may have potential as an adjuvant therapy for acute ischemic stroke when administered via the nasal route.

Stabilization of water-in-water emulsion upon solvent shifting

We report the stabilization of all-aqueous droplets upon addition of ethanol, which were further transformed into robust capsules. An all-aqueous emulsion consisting of dextran (Dex)-rich droplets in a polyethylene glycol (PEG)-rich continuous phase was used as templates. Addition of ethanol induced gelation of dextran, forming aggregated pellets of poor interest. However, this feature was prevented by initially adding bovine serum albumin (BSA) or positively charged silica particles so that in this case, stable droplets formed upon solvent addition, which no longer coalesced with time. An alternative method consisting of pouring concentrated Dex solution in a mixture of PEG, ethanol and BSA or particles, also afforded stable droplets. These stable droplets were further converted into robust capsules, using carbodiimide chemistry or silylation. We expect this method for preparing capsules to be of interest for various applications in the field of microencapsulation.

HIGH-CAPACITY CALCIUM CARBONATE PARTICLES AS PH-SENSITIVE CONTAINERS FOR DOXORUBICIN

Nanostructured submicron calcium carbonate particles with sizes of 500 ± 90 and 172 ± 75 nm have been synthesized by mass crystallization in aqueous solutions with addition of glycerol, as well as a mixture of polyethylene glycol, polysorbate, and a cellular medium. CaCO3 : Si : Fe nanoparticles 65 ± 15 nm in size have been obtained by template synthesis in pores of silica particles. The crystal structure and polymorphism of these particles are studied, and the influence of the size and structure of particles on the efficiency of their loading with a chemotherapy agent , as well as its release under model conditions at different рН, is determined.

Aqueous two-phase extraction: A non-thermal technique to separate and concentrate betalains from Bougainvillea glabra Choisy bracts

The purple bracts of Bougainvillea glabra Choisy contain betalains that can be used as pigmenting agents. The objective was to evaluate the use of aqueous two-phase extraction systems to separate betalains from B. glabra bracts in order to improve the potential of this species as a source of natural pigments. A binodal phase diagram for the mixture of polyethylene glycol 4000 (PEG 4000) and trisodium citrate (Na3Cit; Na3C6H5O7) was studied to select betalain extraction conditions. The separation and concentration of betalains was evaluated and the feasibility of partitioning into betacyanins and betaxanthins was assessed. Mixtures of Na3Cit and PEG 4000 were prepared with concentrations in the ranges of 3.02–39.69% and 0.28–36.98%, respectively, and formed aqueous biphasic systems, with top phases composed mainly by PEG 4000 and bottom phases composed mainly by Na3Cit. The betalains showed a tendency to migrate towards the top phase, with an average separation yield of 92.41% and a concentration of 176.57 mg/L, while in the bottom phase an average content of 4.53 mg/L was found. Such situation was caused by a salting-out phenomenon and by a non-thermal concentration of compounds given by a reduction of the volume ratio between phases. The partition coefficient varied between 18.95 and 183.4 in betacyanins (Bc) and between 6.85 and 80.0 in betaxanthins (Bx). The Bc/Bx ratio varied between 2.82 and 3.26 in top phases and between 1.26 and 1.45 in bottom phases. The use of aqueous two-phase extraction systems allowed betalains to be separated and concentrated, although only a partial partitioning of Bc and Bx was achieved.

In Situ Encapsulation of Phase‐Change Thermal‐Storage Material using 3D Polymer‐Aided Cross‐Linked Porous Carbon

Phase‐change materials are of great interest in solving mismatch between energy supply and demand. However, the vulnerability of solid–liquid phase‐change materials to leakage during the phase‐change process limits their development and application in practice. Herein, the enhancement of the shape stability of phase‐change materials is achieved through an organic–inorganic composite. The mixture of phenolic resin and polyethylene glycol forms a homogeneous solution based on their excellent mutual solubility and is able to be adsorbed into the pores of the expanded graphite by means of a vacuum‐impregnation strategy. The 3D cross‐linked network structure of phenolic resin is formed within the pores of expanded graphite, enabling in situ encapsulation of polyethylene glycol. It is worth noting that the curing reaction of phenolic resin is able to be initiated by heating up without the addition of any curing agent and other auxiliary materials. A thermal conductivity enhancement of 20 times than that of polyethylene glycol is achieved along with a photothermal conversion efficiency of 63.72% and with a latent heat of 134.94 J g−1 without leakage.

Itraconazole-loaded microemulsions: formulation, characterization, and dermal delivery using shed snakeskin as the model membrane

Microemulsions (MEs) were developed for dermal delivery of 1% w/w itraconazole (ITZ). Solubility of ITZ in various oils was investigated and clove oil was selected as oil phase. Pseudoternary phase diagrams were constructed by titration method. The system containing clove oil as oil phase, Tween®80 as surfactant, and 1:1 mixture of water and polyethylene glycol 400 as aqueous phase provided the largest ME region. It was selected for the formulation development of ITZ-loaded MEs. Physicochemical stability was evaluated at 4 °C, room temperature (25 °C), and 45 °C for three months. In vitro permeation and retention studies were assessed using shed snakeskin as a model membrane. Antifungal activity was investigated by agar diffusion method. Results indicated that incorporation of ITZ in the selected MEs did not affect physical properties. Physicochemical data after storage periods revealed that the most suitable storage temperature was 4 °C. Skin permeation and retention data indicated that water-in-oil (w/o) ITZ-loaded MEs had superior dermal delivery of ITZ than oil-in-water (o/w) ITZ-loaded ME and ITZ-oily solution. Moreover, w/o ITZ-loaded MEs showed larger inhibition zones against C. albicans and T. rubrum than a commercial gel. Therefore, w/o ITZ-loaded MEs possibly provided effective dermal delivery and antifungal activity to treat superficial fungal infections.

Novel surface carbon–oxygen-groups grafted TiO2 for selective catalytic reduction of NOx by NH3 at low temperature

Activated coke (AC) with has excellent low-temperature NH3-SCR denitration performance due to its abundant surface-active functional groups including carbon species, while it is easy to burn during industrial application. Herein, a novel surface carbon–oxygen-groups grafted TiO2 was constructed by calcining the solid mixture of polyethylene glycol (PEG) and TiO2. The prepared 0.4PEG/0.6Ti catalyst shows good NH3-SCR denitration activity, and its NOx conversion was up to 80 % above 210 °C, while the pure AC exhibited poor activity. Characterization results suggest that the superior catalytic activity of 0.4PEG/0.6Ti catalyst is mainly attributed to the formation of lactone and carboxyl groups, which can promote the adsorption and activation of NO and NH3 species. Furthermore, NH3 as the reactant can also inhibit the decomposition of carbonyl groups due to over-oxidation, thus 0.4PEG/0.6Ti catalyst has good long-term stability. The reaction mechanism study reveals that the NH3-SCR reactions over catalysts follow the E-R and L-H mechanisms. Finally, the desulfurization-regeneration-denitration test (imitated activated coke simultaneous desulfurization and denitrification process) was carried out, and the results confirm that the prepared PEG/Ti catalyst could be regenerated for denitration after desulfurization. We expect that this work can provide some guidance for the design of low-temperature denitration catalysts.

Prediction of refractive indices and molecular radii of binary mixtures of Polyethylene glycol (PEG-200,400) and cyclic ethers: Insight into molecular interactions

Using five refractive index mixing rules: Lorentz–Lorenz, Gladstone–Dale, Weiner, Heller, and Arago –Biot; refractive indices of six binary polymer mixtures have been determined at 303.15 K, under atmospheric pressure. The binary mixtures investigated here are PEG-200 + 1,3-Dioxolane, PEG-200 + Oxolane, PEG-200 + Oxane, PEG-400 + 1,3-Dioxolane, PEG-400 + Oxolane, and PEG-400 + Oxane. A good agreement has been observed between the obtained results and respective literature data for all these mixtures. The relative merit of refractive index mixing rules is assessed. Deviation in refractive index and reduced free volume values are also calculated using the refractive index data taken from the literature. Furthermore, the molecular radius of these binary polymer mixtures is computed with the help of the refractive index and molar volume data. In addition, an ideal mixing method is also employed to calculate the molecular radius of these systems.The molecular radius of these binary mixtures is found to be additive with respect to the mole fraction of the pure components. Finally, the results are discussed in terms of the intermolecular interactions among the constituent molecules.

Factor causing changes in the mechanical properties of polymer bases of knitted bandages

Knitted wound dressings based on synthetic polymers (primarily lavsan) have some advantages over dressings based on natural materials (cotton, etc.) – first of all, they cause less irritation of wound surfaces due to the absence of microvilli. However, during storage one can see changes in the properties of lavsan dressings, i. e. the material becomes more rigid. Under the present work, it has been shown that these changes are caused by the significantly increased crystallinity of lavsan fibers during exposure to natural environment. To reduce lavsan crystallinity, it is recommended to process the material with mixtures of polyethylene glycols which are popular ointment bases. Heat enhances the effect and returns the original degree of softness to knitted lavsan dressing materials.

Preparation and lubrication properties of graphene oxide/polyethylene glycol/polyvinyl alcohol composite film

In the rotating parts of large mechanical equipment, the existence of friction and wear will inevitably cause energy consumption and loss. Coating a layer of solid lubricating material on the surface of mechanical equipment is an effective means to reduce friction and wear. In this study, for the first time, a composite film with high mechanical and lubricating properties was prepared by hot-pressing the mixture of graphene oxide (GO), polyethylene glycol (PEG), and polyvinyl alcohol (PVA). Its structure and properties were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectroscopy (Raman), and thermogravimetric analysis (TGA). The lubrication and tribological properties of GO-PEG-PVA composite film and other single films under different lubrication conditions were analyzed. The lubrication characteristics of GO-PEG-PVA composite film under oil lubrication were discussed in detail. The results show that the surface coating with GO-PEG-PVA can ensure a lower friction coefficient, especially in the condition of oil lubrication, the friction coefficient is 82% lower than that without oil film. The hot pressing process ensures that the surface morphology will not produce large shear deformation. The lubrication mechanism and lubrication model were discussed in detail, and the concept of improving surface lubrication performance by co-lubrication was put forward.

Three-Dimensional Printable, Highly Conductive Ionic Elastomers for High-Sensitivity Iontronics.

The development of hydrogels and ionic gels for applications in fields such as soft electronics and wearable sensors is limited by liquid evaporation or leakage. Ionic conductors without volatile liquids are better choices for flexible and transparent devices. Here, a liquid polymer electrolyte (LPE) is prepared from a mixture of lithium bis(trifluoromethane)sulfonimide and polyethylene glycol (PEG) above the melting point of PEG. A three-dimensional (3D) printable solvent-free ionic elastomer (IE) is introduced by photopolymerization of ethyl acrylate and hydroxyethyl acrylate in the prepared LPE. The conductivity is significantly improved by the presence of a high content of the lithium salt. Dynamic cross-linking networks improve the stretchability and resilience of the elastomer. The pattern design capability of the IE is provided by light-curing 3D printing. These features demonstrate that the IE has broad application prospects in flexible sensors, ion skins, and soft robots.

An injectable thermosensitive hydrogel/nanomicelles composite for local chemo-immunotherapy in mouse model of melanoma.

Recently, cancer immunotherapy and its combination with chemotherapy has been considered to improve therapeutic efficacy with lower systemic toxicity. Here, we prepared a thermosensitive hydrogel based hyaluronic acid (HA) encapsulated with macrophage colony-stimulating factor (GM-CSF) and paclitaxel (PTX) for chemoimmunotherapy of cancer. For this purpose, the micelles were prepared with the mixture of pluronic F127 (PF127) and tocopheryl polyethylene glycol (TPGS) and loaded with PTX. In the following step, thermosensitive hydrogel using PF127 and HA was prepared and co-encapsulated with the micelles and GM-CSF. Rheological performance, friability, release patterns for PTX and GM-CSF, and stability of GM-CSF in the hydrogel were evaluated in details. In-vitro and in vivo immunologic activities of GM-CSF in the hydrogel were also evaluated via numbering macrophages and recruited DCs in transwells and after subcutaneous injection of the GM-CSF-loaded hydrogel. Finally, mouse model of subcutaneous melanoma was induced in female C57 mice using B16 F10 cell line and the effect of optimized formulation was evaluated based on tumor volume and histological analysis. The hydrogel could maintain the biological activity of the incorporated drugs and exhibited a more prolonged release for PTX compared to GM-CSF. GM-CSF-releasing HA/PF127 hydrogel successfully recruited macrophages in vitro. Moreover, the most potent anti-tumor effect was observed following the intra-tumoral injection of the optimized formulation in melanoma bearing mice, compared to immunization by the GM-CSF and PTX alone. The current formulation shows a great promise to conquer resistant malignancies and provides a new approach for co-encapsulating of hydrophobic anticancer drugs and growth factor.

Physicochemical studies of polyethylene glycols in aqueous biotin solutions at different temperatures and constant pressure

Density and speed of sound of polyethylene glycols (polyethylene glycol 200; polyethylene glycol 400) in (0.000, 0.0024, 0.0032, and 0.0040) mol·Kg-1aqueous solutions of biotin at constant experimental pressure 0.1 MPa and temperature range (288.15 K, 298.15 K, 308.15 K and 318.15 K) have been obtained using Anton-Paar DSA 5000 M. These experimental data were used to calculate various acoustic and thermodynamic parameters such as intermolecular free length, acoustic impedance, adiabatic compressibility, Wada’s constant, Rao’s Constant and Vander Waal’s constant which gave the insight of the intermolecular reactions inside the ternary mixture of vitamin B7(Biotin) and polyethylene glycols (PEG 200/PEG 400).

Thermophysical and conductometric study of lithium perchlorate in binary aqueous mixture of polyethylene glycol (PEG-400)

In the present study apparent molar volume, partial molar volume, viscosity and conductance parameters of lithium perchlorate (LiClO4) in 0.01m, 0.03m and 0.05m aqueous polyethylene glycol (PEG-400) have been determined by using density, viscosity and conductance data at five equidistant temperatures 298.15K, 303.15K, 308.15K, 313.15K and 318.15K. Data is analysed in terms of various molecular interactions by using Masson’s and Jones-Dole equations. The structure making/breaking behaviour of LiClO4 is interpreted from 2 the sign of [∂2 ϕv°/∂T2], dB/dT and temperature coefficient of Walden product i.e., d(Λm°η°)/dT values. In the present study LiClO4 has been found as structure-maker in 0.01 m, 0.03m and 0.05m aqueous polyethylene glycol (PEG-400).

Study of Hydrogen Sulfide Adsorption on Silica Gel with Triethanolamine layer

Hydrogen sulfide (H2S) is an impurity in gaseous fuels such as biogas, therefore this gas removal method is an interesting topic. The physisorption method is considered to be a simple work to be applied on a small scale. This research studies the impact of the addition of liquid triethanolamine on the porous silica on the adsorption of H2S. The silica substrate is synthesized using two-pore templates namely a mixture of polyethylene glycol (PEG)/ sodium dodecyl sulfate (SDS) and the other one is pure chitosan. The silica surface was coated with triethanolamine (TEA) using the impregnation method. An H2S gas adsorption study was conducted on the synthesized silica with and without TEA. The adsorption test was carried out by flowing H2S from the reaction between FeS and HCl through the sample. The results of this study show that the TEA layer on the silica surface increases the adsorption towards H2S gas, but it is relatively small compared to similar studies. The best result of combining TEA and silica gel is shown by TEA- sil-PS which was 3.8 x 10-5 mol H2S per gram of adsorbent.