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Gels (Basel, Switzerland) Dec 2023Hydrogel has been widely used in reservoir regulation for enhancing oil recovery, however, this process can experience negative influences on the properties and effects...
Hydrogel has been widely used in reservoir regulation for enhancing oil recovery, however, this process can experience negative influences on the properties and effects of the hydrogels. Therefore, developing novel hydrogels with excellent environmental responsiveness would improve the formation adaptability of hydrogels. In this study, novel polyvinyl polyamine hydrogels were synthesized by a ring-opening addition reaction between polyvinyl polyamines and polyethylene glycol glycidyl ether. The results of atomic force microscopy and transmission electron microscopy showed that the polyvinyl polyamine gel had a porous and irregular bulk structure and was endowed with water storage. With the temperature rising from 30 °C to 60 °C, the transmittance of diethylenetriamine hydrogel decreased from 84.3% to 18.8%, indicating that a phase transition had occurred. After the polyvinyl polyamine hydrogel with low initial viscosity was injected into the formation in the liquid phase, the increase of the reservoir temperature caused it to turn into an elastomer, thereby migrating to the depth of the reservoir and achieving effective plugging. Polyvinyl polyamine hydrogel could improve the profile of heterogeneous layers significantly by forcing subsequent fluids into the low permeability zone in the form of elastomers in the medium temperature reservoirs of 40-60 °C. The novel environmentally responsive polyvinyl polyamine hydrogels, capable of phase transformation with temperature, exhibited superior performance in recovering residual oil, which was beneficial for applications in reservoir profile control and oilfield development.
PubMed: 38131936
DOI: 10.3390/gels9120950 -
Polymers Nov 2023The citric acid (CA) cross-linked polyvinyl alcohol (PVA) adsorbent, PVA-CA, was efficiently synthesized and its application to the removal of dyes in water,...
The citric acid (CA) cross-linked polyvinyl alcohol (PVA) adsorbent, PVA-CA, was efficiently synthesized and its application to the removal of dyes in water, particularly the cationic dye, methylene blue (MB), was thoroughly investigated. The morphologies and physiochemical characteristics of PVA-CA were fully characterized by SEM, FT-IR, XRD, TGA, BET, and XPS. The effects of contact time, adsorbent dosage, MB concentration, solution pH, and temperature on the adsorption performance were compared using controllable methods. The maximum adsorption capacity of PVA-CA was 709.86 mg g and the removal rate remained high through several adsorption-desorption cycles, demonstrating that such a composite absorbent has a good adsorption performance and recoverability. Further analysis by the density functional theory (DFT) showed that van der Waals interactions, electrostatic interactions and hydrogen bonding interactions between PVA-CA and MB played significant roles in the adsorption mechanism.
PubMed: 38006066
DOI: 10.3390/polym15224341 -
Saudi Pharmaceutical Journal : SPJ :... Sep 2023The aim of this study is to formulate polymeric paclitaxel nanoparticles with various stabilizers to improve solubility, enhance stability, maximize therapeutic efficacy...
The aim of this study is to formulate polymeric paclitaxel nanoparticles with various stabilizers to improve solubility, enhance stability, maximize therapeutic efficacy and minimize detrimental toxicities of paclitaxel. In this study, trastuzumab-guided poly lactic-co-glycolic acid (PLGA)-loaded paclitaxel nanoparticles were formulated with pluronic F-127, polyvinyl alcohol (PVA), poloxamer 407, Tween-80, span 20, sodium dodecyl sulfate (SDS), and sodium lauryl sulfate (SLS) at different concentrations (0.5, 1, 1.5 and 2%) using the solvent evaporation method. The nanoparticles were evaluated for physicochemical characteristics and short and long-term stability. The optimum particle size (190 nm ± 12.42 to 350 nm ± 11.1), PDI (0.13 ± 0.02 to 0.2 ± 0.01), surface charge (-19.1mv ± 1.5 to -40.4mv ± 1.6), drug loading (2.43 to 9.5 %) and encapsulation efficiency (greater than 80 %) were obtained with these stabilizers while keeping the polymer concentration, temperature, probe size, amplitude and sonication time constant. The nanoformulations were stably stored at 4 °C. The nanoformulations of paclitaxel with pluronic F-127, polyvinyl alcohol (PVA), and poloxamer 407 were found to be more soluble, stable, uniform in physicochemical properties, and efficient in drug loading and encapsulation for improved therapeutic effects.
PubMed: 37559864
DOI: 10.1016/j.jsps.2023.101697 -
Molecular Pharmaceutics Sep 2023The aim of the present study was to investigate how different polymers affect the dissociation of cocrystals prepared by co-spray-drying active pharmaceutical ingredient...
The aim of the present study was to investigate how different polymers affect the dissociation of cocrystals prepared by co-spray-drying active pharmaceutical ingredient (API), coformer, and polymer. Diclofenac acid-l-proline cocrystal (DPCC) was selected in this study as a model cocrystal due to its previously reported poor physical stability in a high-humidity environment. Polymers investigated include polyvinylpyrrolidone (PVP), poly(1-vinylpyrrolidone--vinyl acetate) (PVPVA), hydroxypropyl methyl cellulose, hydroxypropylmethylcellulose acetate succinate, ethyl cellulose, and Eudragit L-100. Terahertz Raman spectroscopy (THz Raman) and powder X-ray diffraction (PXRD) were used to monitor the cocrystal dissociation rate in a high-humidity environment. A Raman probe was used to monitor the extent of the dissociation of DPCC and DPCC in crystalline solid dispersions (CSDs) with polymer when exposed to pH 6.8 phosphate buffer and water. The solubility of DPCC and solid dispersions of DPCC in pH 6.8 phosphate buffer and water was also measured. The dissociation of DPCC was water-mediated, and more than 60% of DPCC dissociated in 18 h at 40 °C and 95% RH. Interestingly, the physical stability of the cocrystal was effectively improved by producing CSDs with polymers. The inclusion of just 1 wt % polymer in a CSD with DPCC protected the cocrystal from dissociation over 18 h under the same conditions. Furthermore, the CSD with PVPVA was still partially stable, and the CSD with PVP was stable (undissociated) after 7 days. The superior stability of DPCC in CSDs with PVP and PVPVA was also demonstrated when systems were exposed to water or pH 6.8 phosphate buffer and resulted in higher dynamic solubility of the CSDs compared to DPCC alone. The improvement in physical stability of the cocrystal in CSDs was thought to be due to an efficient mixing between polymer and cocrystal at the molecular level provided by spray drying and gelling of polymer. It is hypothesized that polymer chains could undergo gelling and form a physical barrier, preventing cocrystal interaction with water, which contributes to slowing down the water-mediated dissociation.
Topics: Polymers; Spray Drying; Povidone; X-Ray Diffraction; Phosphates
PubMed: 37595572
DOI: 10.1021/acs.molpharmaceut.3c00564 -
International Journal of Biological... Jul 2023Thermoplastic starch/polyvinyl alcohol (TPS/PVA) films have limitations for being used in long-term applications due to starch retrogradation. This leads to plasticizer...
Thermoplastic starch/polyvinyl alcohol (TPS/PVA) films have limitations for being used in long-term applications due to starch retrogradation. This leads to plasticizer migration, especially when low molecular weight plasticizers such as glycerol, are used. In this work, we employed mixtures of oligomers based on glycerol citrates with higher molecular weight than glycerol as plasticizers for potato-based TPS/PVA blends obtained by melt-mixing. This constitutes an alternative to reduce plasticizer migration while keeping high swelling degree, and to provide high mechanical performance. The novelty lies in the usage of these oligomers by melt-mixing technique, aspect not deeply explored previously and that represents the first step towards industrial scalability. Prior to the blending process, oligomers mixtures were prepared with different molar ratios of citric acid (0-40 mol%) and added them. This minimizes the undesirable hydrolysis effect of free carboxylic groups on starch chains. The results demonstrated that the migration of plasticizers in TPS/PVA blends decreased by up to 70 % when the citric acid content increased. This reduction was attributed to the higher molecular weight (the majority in the range 764-2060 Da) and the 3D structure of the oligomers compared to using raw glycerol. Furthermore, the films exhibited a 150 % increase in Young's modulus and tensile strength without a reduction in elongation at break, while maintaining a high gel content, due to a moderate crosslinking.
Topics: Polyvinyl Alcohol; Plasticizers; Glycerol; Polyesters; Citric Acid; Starch
PubMed: 37336376
DOI: 10.1016/j.ijbiomac.2023.125478 -
Polymers Sep 2023The combination of a nanofibre net and textile support represents an interesting composite capable of conferring various properties. Nanofibres are so thin that they can...
The combination of a nanofibre net and textile support represents an interesting composite capable of conferring various properties. Nanofibres are so thin that they can be easily damaged by human touch. In this study, we hypothesised that dyeing nanofibres with different colours from their textile supports would result in a colour difference upon their degradation, providing evidence that the composite has been touched and acting as a touch sensor. Two different methods were studied: directly inserting the dye into the polymer via electrospinning or creating a coloured liquid emulsion encapsulated by the polymer via electrospinning. Two black dyes were studied. Colour index (CI) Acid Black 194 was added directly to polyvinyl alcohol (PVA) as the polymer. Sage oil was used for CI Solvent Black 3. The nanofibre nets were conveniently electrospun on a white polyester fabric; the fabrics were then characterised by colour coordinate analysis, FTIR, and SEM. The results showed that the dyed solution in oil was encapsulated, and the black colour could only be observed when rubbed, whereas the dyed polymer showed a black colour that was removed when rubbed. Therefore, the hypothesis was confirmed, and both samples demonstrated the desired touch sensor behaviour.
PubMed: 37835951
DOI: 10.3390/polym15193903 -
Nanomaterials (Basel, Switzerland) Dec 2023This study focuses on the fabrication of polymer nanocomposite films using polyvinyl alcohol (PVA)/graphene quantum dots (GQDs). We investigate the relationship between...
This study focuses on the fabrication of polymer nanocomposite films using polyvinyl alcohol (PVA)/graphene quantum dots (GQDs). We investigate the relationship between the structural, thermal, and nanoscale morphological properties of these films and their photoluminescent response. Although according to X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and differential thermal analysis (DTA), the incorporation of GQDs does not significantly affect the percentage crystallinity of the PVA matrix, for a range of added GQD concentrations, atomic force microscopy (AFM) showed the formation of islands with apparent crystalline morphology on the surface of the PVA/GQD films. This observation suggests that GQDs presumably act as nucleating agents for island growth. The incorporation of GQDs also led to the formation of characteristic surface pores with increased stiffness and frictional contrast, as indicated by ultrasonic force microscopy (UFM) and frictional force microscopy (FFM) data. The photoluminescence (PL) spectra of the films were found to depend both on the amount of GQDs incorporated and on the film morphology. For GQD loads >1.2%wt, a GQD-related band was observed at ~1650 cm in FT-IR, along with an increase in the PL band at lower energy. For a load of ~2%wt GQDs, the surface morphology was characterized by extended cluster aggregates with lower stiffness and friction than the surrounding matrix, and the PL signal decreased.
PubMed: 38202460
DOI: 10.3390/nano14010005 -
Polymers Dec 2023In this study, a new strategy was adopted for obtaining polymer/protein hybrid hydrogels with shape stability and tunable mechanical or rheological characteristics by...
In this study, a new strategy was adopted for obtaining polymer/protein hybrid hydrogels with shape stability and tunable mechanical or rheological characteristics by using non-toxic procedures. A chemical network was created using a poly(vinyl alcohol)(PVA)/bovine serum albumin (BSA) mixture in aqueous solution in the presence of genipin and reduced glutathione (GSH). Then, a second physical network was formed through PVA after applying freezing/thawing cycles. In addition, the protein macromolecules formed intermolecular disulfide bridges in the presence of GSH. In these conditions, multiple crosslinked networks were obtained, determining the strengthening and stiffening into relatively tough porous hydrogels with tunable viscoelasticity and a self-healing ability. A SEM analysis evidenced the formation of networks with interconnected pores of sizes between 20 μm and 50 μm. The mechanical or rheological investigations showed that the hydrogels' strength and response in different conditions of deformation were influenced by the composition and crosslinking procedure. Thus, the dynamics of the hybrid hydrogels can be adjusted to mimic the viscoelastic properties of the native tissues. The dynamic water vapor-sorption ability, swelling behavior in an aqueous environment, and bioadhesive properties were also investigated and are discussed in this paper. The hybrid hydrogels with tunable viscoelasticity can be designed on request, and they are promising candidates for tissue engineering, bioinks, and wound dressing applications.
PubMed: 38232047
DOI: 10.3390/polym15234611 -
Scientific Reports May 2024The supercritical antisolvent (SAS) process was a green alternative to improve the low bioavailability of insoluble drugs. However, it is difficult for SAS process to...
The supercritical antisolvent (SAS) process was a green alternative to improve the low bioavailability of insoluble drugs. However, it is difficult for SAS process to industrialize with limited production capacity. A coaxial annular nozzle was used to prepare the microcapsules of aprepitant (APR) and polyvinylpyrrolidone (PVP) by SAS with N, N-Dimethylformamide (DMF) as solvent. Meanwhile, the effects of polymer/drug ratio, operating pressure, operating temperature and overall concentration on particles morphology, mean particle diameter and size distribution were analyzed. Microcapsules with mean diameters ranging from 2.04 μm and 9.84 μm were successfully produced. The morphology, particle size, thermal behavior, crystallinity, drug content, drug dissolution and residual amount of DMF of samples were analyzed. The results revealed that the APR drug dissolution of the microcapsules by SAS process was faster than the unprocessed APR. Furthermore, the drug powder collected every hour is in the kilogram level, verifying the possibility to scale up the production of pharmaceuticals employing the SAS process from an industrial point of view.
Topics: Capsules; Povidone; Solvents; Aprepitant; Particle Size; Solubility; Dimethylformamide; Drug Liberation; Drug Compounding; Temperature
PubMed: 38724534
DOI: 10.1038/s41598-024-60323-z -
Heliyon Nov 2023Cancer recurrence following surgery is a serious and worrying problem for the patient. Common treatment strategies, such as chemotherapy, radiotherapy, and surgery, are...
Cancer recurrence following surgery is a serious and worrying problem for the patient. Common treatment strategies, such as chemotherapy, radiotherapy, and surgery, are restricted because of low uptake of the drugs, poor pharmacokinetic properties, and toxicity issues for healthy tissues. The development of engineering platforms for improving the postoperative treatment of cancer can help solve this problem. In this study, the ceria-tannic acid nanoparticles (CeTA-NPs) were successfully synthesized and characterized. Chitosan-polyvinyl/alcohol (S-PVA) hydrogels containing CeTA NPs (S-PVA/CeTA) and amygdalin as an anticancer substance were fabricated using freeze-thaw and immersion-drying techniques. The swelling and degradation behaviors, antibacterial activity, and biocompatibility of as-prepared hydrogel were done. The apoptotic effects of amygdalin/CS-PVA/CeTA hydrogel were evaluated by flow cytometry technique on a human colorectal cancer (SW-480) cell line. The CeTA-NPs were investigated as antibacterial and cross-linker agents for greater stability of the hydrogel network. The S-PVA/CeTA hydrogel demonstrated good safety and antibacterial activity. The results of swelling and biodegradation suggest that S-PVA/CeTA hydrogels can inspire long-time application. The anticancer effects of the amygdalin/CS-PVA/CeTA hydrogel were confirmed by apoptosis results. Hence, amygdalin/CS-PVA/CeTA hydrogel can be a promising candidate for long-time biomedical application.
PubMed: 38027646
DOI: 10.1016/j.heliyon.2023.e21835