Synergistic Effect Of Polymers Research Articles

Synergistic effect of polymers in stabilizing amorphous pretomanid through high drug loaded amorphous solid dispersion.

Pretomanid (PTM), an oral antibiotic used in the treatment of adults with pulmonary extensively drug-resistant, nonresponsive multidrug-resistant tuberculosis (MDR-TB). It is a poor glass former, that shows high recrystallization tendency from the amorphous and supersaturated state, resulting in low aqueous solubility and suboptimal absorption through the gastrointestinal tract. The present investigation aimed to develop high drug loaded ternary amorphous solid dispersions (ASDs) of PTM with improved stability and enhanced biopharmaceutical performance by utilizing a combination of polymers. The polymers were comprehensively screened based on drug-polymer miscibility and saturation solubility analysis. A combination of Hydroxypropyl Methylcellulose Acetate Succinate (HPMCAS-HF) and Polyvinylpyrrolidone K-30 (PVP K-30) showed synergism in drug-polymer miscibility as evidenced through pronounced depression in the melting endotherm of PTM. The Powder X-ray Diffraction (P-XRD) diffractograms of 30% w/w PTM loaded ternary ASDs displayed the halo pattern, contrary to the binary ASDs. Drug-polymer interactions (hydrophobic forces) involved between PTM and polymers were detected through Fourier Transform Infrared Spectroscopy (FT-IR) and Nuclear Magnetic Resonance Spectroscopy (13C-NMR) which contributed to the synergistic enhancement in solubility and dissolution of ternary ASDs with sustained release over 12h. Ternary ASDs demonstrated better in-vivo performance compared to the binary ASDs, showing a 4.63-fold increase in maximum plasma concentration. All ASDs remained stable and resisted phase separation during short-term stability studies for 3 months at ambient conditions. It was concluded that the hydrophobic and hydrophilic polymeric combination (HPMCAS-HF and PVP K-30, respectively) effectively prevented the crystallization and ensured sustained drug release with improved in-vivo absorption of PTM.

Preparation and Functionalization of Polymers with Antibacterial Properties-Review of the Recent Developments.

The presence of antibiotic-resistant bacteria in our environment is a matter of growing concern. Consumption of contaminated drinking water or contaminated fruit or vegetables can provoke ailments and even diseases, mainly in the digestive system. In this work, we present the latest data on the ability to remove bacteria from potable water and wastewater. The article discusses the mechanisms of the antibacterial activity of polymers, consisting of the electrostatic interaction between bacterial cells and the surface of natural and synthetic polymers functionalized with metal cations (polydopamine modified with silver nanoparticles, starch modified with quaternary ammonium or halogenated benzene). The synergistic effect of polymers (N-alkylaminated chitosan, silver doped polyoxometalate, modified poly(aspartic acid)) with antibiotics has also been described, allowing for precise targeting of drugs to infected cells as a preventive measure against the excessive spread of antibiotics, leading to drug resistance among bacteria. Cationic polymers, polymers obtained from essential oils (EOs), or natural polymers modified with organic acids are promising materials in the removal of harmful bacteria. Antimicrobial polymers are successfully used as biocides due to their acceptable toxicity, low production costs, chemical stability, and high adsorption capacity thanks to multi-point attachment to microorganisms. New achievements in the field of polymer surface modification in order to impart antimicrobial properties were summarized.

Synergistic effect of polymer and nanoparticles on shale hydration and swelling performance of drilling fluids

The inhibition attributes of drilling formulations typically rely on the type of additives, concentration, and reactivity with shale formations. In this work, the impact of ZnO and polymer on rheological, shale inhibition, and filtration properties were studied. Several drilling formulations were prepared with different concentrations of ZnO and polymer in the deionized water. Rheological properties (viscosity, yield stress, and gel strengths) were measured using a hybrid rheometer to investigate drilling formulation performance. The filtration properties drilling formulations and permeability analysis of filter cake was performed to analyze the impact of ZnO and associative polymer on fluid loss. SEM-EDS analysis of filter cake was accomplished to investigate the dispersion of drilling additives on filter cake. Shale swelling inhibition characteristics of drilling formulations were determined by performing shale dispersion test and linear swelling test as per API standards. The shale dispersion test showed 97% shale recovery with BPN4 formulation compared to 81% of shale recovery with the base formulation. Shale swelling rate decreased to 6.69% with BPN4 formulation compared to the 14.29% of shale swelling rate in the base formulation. Shale inhibition results showed that the synergic impact of ZnO and polymer in the formulations enhanced the inhibition characteristics. Contact angle measurements showed that synergy of ZnO and polymer in the drilling formulation increased the hydrophobicity of the shale surface. Hence, drilling formulations comprising both ZnO and polymer can be applied to drilling operations for superior inhibition characteristics.

Graphene and polydopamine double-wrapped porous carbon-sulfur cathode materials for lithium-sulfur batteries with high capacity and cycling stability

Rechargeable lithium-sulfur batteries are deemed to be a promising energy supply to next-generation high energy power system, yet dissolution of lithium polysulfides in the electrolyte leads to poor cycling performance. Here, we report an approach to assemble graphene and polydopamine double-wrapped porous carbon/sulfur (GN-PD-PC-S) for lithium-sulfur batteries. Remarkably, the double-wrapping graphene and polydopamine further help confine the sulfur and polysulfides inside the mesopores and micropores of porous carbon. Moreover, the hierarchical porous structures provide a conductive network for electron transfer and facilitate the effective accommodation of the volume change of sulfur. The GN-PD-PC-S cathode presents an excellent cycling stability of 821 mAh g−1 after 100 cycles, with a favorable high-rate capability of 496 mAh g−1 at a current density of 2 A g−1. Our results indicate the importance of chemically synergistic effect of polymer and carbon in the electrode system for achieving high-performance electrodes in rechargeable lithium-sulfur batteries.

Synergistic effect of polymer and small molecules for high-performance ternary organic solar cells.

A ternary blend system with two donors and one acceptor provides an effective route to improve the performance of organic solar cells. A synergistic effect of polymer and small molecules is observed in ternary solar cells, and the power conversion efficiency (PCE) of the ternary system (8.40%) is higher than those of binary systems based on small molecules (7.48%) or polymers (6.85%).

Synergistic effect of polymer and oligomer blends for solution-processable organic thin-film transistors

The thin-film morphologies and thin-film transistor (TFT) characteristics of a series of binary blends of poly(9,9′-dioctylfluorene- alt-bithiophene) (F8T2) and α, ω-dihexylquarterthiophene (DH4T) are reported. The blends of F8T2 and DH4T exhibit good solubility and produce TFT devices with better performances than F8T2 and DH4T devices. The 50% DH4T blend device was found to have a hole mobility of 0.011 cm 2 V −1 s −1, which is four times higher than the mobility of the F8T2 device, with a high-on/off ratio of about 10 5 and a low-off current of 17 pA. The polymer and oligomer domains are phase-separated with large domain size and arranged in characteristic molecular alignments. It was found that carrier transport in the blend systems is mainly controlled by the polymer component, and that the nature of the blended oligomer affects the OTFT performance of the blends.

Rheological properties of solutions and gels of combined systems hydrophobically modified polyacrylamides-new viscoelastic cationic surfactants

The rheological properties (viscosity and dynamic elasticity modulus) of solutions and gels of combined systems composed of hydrophobically modified polymers containing main-chain charged groups or lacking these groups and of newly synthesized viscoelastic cationic surfactants with different amounts of OH groups and long nonpolar saturated and trans monounsaturated radicals have been studied. It has been shown that the maximum viscosity of solutions of polymer-surfactant complexes corresponds to the very low concentration of the surfactant. Regions where homogeneous and heterogeneous combined solutions and gels exist are considered. An increase in the viscosity of the combined solutions with temperature is discovered and discussed. The synergistic effect of polymers and surfactants is demonstrated, and a more efficient role of surfactants in the case of uncharged polymers is revealed. The roles of the number of OH groups and the length of the nonpolar radical in a surfactant molecule and a difference in the properties of systems containing surfactants with saturated and unsaturated radicals are considered.