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Journal of Pharmaceutical Sciences Apr 2021In present work, a correlationship among quantitative drug-polymer miscibility, molecular relaxation and phase behavior of the dipyridamole (DPD) amorphous solid...
In present work, a correlationship among quantitative drug-polymer miscibility, molecular relaxation and phase behavior of the dipyridamole (DPD) amorphous solid dispersions (ASDs), prepared with co-povidone (CP), hydroxypropyl methylcellulose phthalate (HPMC P) and hydroxypropyl methylcellulose acetate succinate (HPMC AS) has been investigated. Miscibility predicted using melting point depression approach for DPD with CP, HPMC P and HPMC AS at 25 °C was 0.93% w/w, 0.55% w/w and 0.40% w/w, respectively. Stretched relaxation time (τ) for DPD ASDs, measured using modulated differential scanning calorimetry (MDSC) at common degree of undercooling, was in the order of DPD- CP > DPD-HPMC P > DPD-HPMC AS ASDs. Phase behavior of 12 months aged (25 ± 5 °C and 0% RH) spray dried 60% w/w ASDs was tracked using MDSC. Initial ASD samples had homogeneous phase revealed by single glass transition temperature (T) in the MDSC. MDSC study of aged ASDs revealed single-phase DPD-CP ASD, amorphous-amorphous and amorphous-crystalline phase separated DPD-HPMC P and DPD-HPMC AS ASDs, respectively. The results were supported by X-ray micro computed tomography and confocal laser scanning microscopy studies. This study demonstrated a profound influence of drug-polymer miscibility on molecular mobility and phase behavior of ASDs. This knowledge can help in designing "physical stable" ASDs.
Topics: Calorimetry, Differential Scanning; Dipyridamole; Pharmaceutical Preparations; Polymers; Solubility; X-Ray Microtomography
PubMed: 33333143
DOI: 10.1016/j.xphs.2020.12.007 -
International Journal of Molecular... Apr 2023The interest in polymers with high thermal conductivity increased much because of their inherent properties such as low density, low cost, flexibility, and good chemical...
The interest in polymers with high thermal conductivity increased much because of their inherent properties such as low density, low cost, flexibility, and good chemical resistance. However, it is challenging to engineer plastics with good heat transfer characteristics, processability, and required strength. Improving the degree of the chain alignment and forming a continuous thermal conduction network is expected to enhance thermal conductivity. This research aimed to develop polymers with a high thermal conductivity that can be interesting for several applications. Two polymers, namely poly(benzofuran-co-arylacetic acid) and poly(tartronic--glycolic acid), with high thermal conductivity containing microscopically ordered structures were prepared by performing enzyme-catalyzed (Novozyme-435) polymerization of the corresponding α-hydroxy acids 4-hydroxymandelic acid and tartronic acid, respectively. A comparison between the polymer's structure and heat transfer obtained by mere thermal polymerization before and enzyme-catalyzed polymerization will now be discussed, revealing a dramatic increase in thermal conductivity in the latter case. The polymer structures were investigated by FTIR spectroscopy, nuclear magnetic resonance (NMR) spectroscopy in liquid- and solid-state (-NMR), and powder X-ray diffraction. The thermal conductivity and diffusivity were measured using the transient plane source technique.
Topics: Polymers; Thermal Conductivity; Lipase; Magnetic Resonance Spectroscopy
PubMed: 37108765
DOI: 10.3390/ijms24087606 -
Chemical Communications (Cambridge,... Jan 2015Enzyme-responsive polymer assemblies have proved to be promising candidates for biomaterials, biomedicine and biosensing. Traditionally, these assemblies are prepared by...
Enzyme-responsive polymer assemblies have proved to be promising candidates for biomaterials, biomedicine and biosensing. Traditionally, these assemblies are prepared by the self-assembly of polymer building blocks which are covalently conjugated with enzyme-responsive moieties. Moreover, a supramolecular strategy has recently been developed for the preparation of enzyme-responsive polymer assemblies where the enzyme-responsive moieties are non-covalently complexed with the polymer building blocks. In addition, kinetic studies have been conducted on the enzyme-responsive behaviour of the polymer assemblies, which paves the way for tuning the response rate of the assemblies in a controlled manner.
Topics: Enzymes; Kinetics; Micelles; Molecular Structure; Nanoparticles; Polymers
PubMed: 25360449
DOI: 10.1039/c4cc05878j -
ACS Applied Bio Materials Mar 2022Magnetic resonance imaging-aided real-time diagnosis along with enhanced chemotherapeutic efficacy using a sequential receptor and mitochondria dual-targeting polymer...
Magnetic resonance imaging-aided real-time diagnosis along with enhanced chemotherapeutic efficacy using a sequential receptor and mitochondria dual-targeting polymer theranostic has become a promising strategy for the effective and precise treatment of cancer. Toward the accomplishment of this goal, chlorambucil (chemotherapeutic agent), biotin (receptor targeting agent), a triphenylphosphonium segment (mitochondriotropic agent), and an iron rhodamine complex (integrated fluorescence-MR imaging agent) were tethered under a single polymer. Owing to the polymer's () amphiphilic character, it spontaneously self-assembled into nanospheres, which exhibited a remarkable effect on the relaxation of the water proton. Further, the qualitative estimation of the change in intensity for the water-proton signal reflected its potential as a T contrast theranostic polymer. The mitochondria targeting competency of positively charged nanospheres was displayed using fluorescence microscopy in human cervical, , and breast, , carcinoma cell lines. Furthermore, cytotoxicity experiments demonstrated the enhanced anticancer efficacy in both cancer cell lines. Therefore, effective and precise chemotherapy through sequential receptor-mitochondria targeting and integrated fluorescence-MR imaging would have attractive potential for decisive dose-determination by constantly monitoring the subject area of interest.
Topics: Coloring Agents; Humans; Iron; Magnetic Resonance Imaging; Mitochondria; Neoplasms; Polymers; Protons; Theranostic Nanomedicine; Water
PubMed: 35189682
DOI: 10.1021/acsabm.1c01300 -
Chemical & Pharmaceutical Bulletin 2021Multifunctional synthetic polymers can bind to target molecules and are therefore widely investigated in diagnostics, drug delivery carriers, and separation carriers....
Multifunctional synthetic polymers can bind to target molecules and are therefore widely investigated in diagnostics, drug delivery carriers, and separation carriers. Because these polymers are synthesized from nonbiological components, purification processes (e.g., chromatography, dialysis, extraction, and centrifugation) must be conducted after the synthesis. Although several purification methods are used for polymer purification, few reports have revealed the influence of purification process on the functions of polymer. In this study, we demonstrated that the characteristics, function, and stability of synthetic polymer depend on the purification process. N-Isopropylacrylamide-based polymer nanoparticles (NPs) and melittin (i.e., honey bee venom) were used as a model of synthetic polymer and target toxic peptide, respectively. Synthesized NPs were purified by dialysis in methanol, acetone precipitation, or centrifugation. NPs purified by dialysis in ultrapure water were used as control NPs. Then, NP size, surface charge, toxin neutralization effect, and stability were determined. NP size did not considerably change by purification with centrifugation; however, it decreased by purification using dialysis in methanol and acetone precipitation compared with that of control NPs. The ζ-potential of NPs changed after each purification process compared with that of control NPs. The melittin neutralization efficiency of NPs depended on the purification process; i.e., it decreased by acetone precipitation and increased by dialysis in methanol and centrifugation compared with that of control NPs. Of note, the addition of methanol and acetone decreased NP stability. These studies implied the importance of considering the effect of the purification method on synthetic polymer function.
Topics: Molecular Structure; Nanoparticles; Polymers
PubMed: 34334521
DOI: 10.1248/cpb.c21-00273 -
Macromolecular Rapid Communications Jul 2011Will polytellurophenes bridge the gap between conjugated polymer and inorganic solid-state semiconductors? Polytellurophenes are a virtually unexplored class of...
Will polytellurophenes bridge the gap between conjugated polymer and inorganic solid-state semiconductors? Polytellurophenes are a virtually unexplored class of conjugated polymer. In this paper, the synthetic methodologies that have been used to prepare polytellurophenes are chronicled. The properties of the resulting polymers are discussed and their potential for use as electronic materials is evaluated. It is far too early to know if these materials will lead to a useful class of thin-film semiconductors, however some key challenges associated with their synthesis and implementation are outlined. These challenges will need to be addressed as the conjugated polymer research community begins to utilize this area of the periodic table.
Topics: Chemistry, Organic; Polymers; Tellurium; Thiophenes
PubMed: 21538646
DOI: 10.1002/marc.201100151 -
Angewandte Chemie (International Ed. in... Apr 2015A synthetic strategy is reported for the production of a trefoil knotted polymer from a copper(I)-templated helical knot precursor through ring expansion. The expected...
A synthetic strategy is reported for the production of a trefoil knotted polymer from a copper(I)-templated helical knot precursor through ring expansion. The expected changes in the properties of the knotted polymer compared to a linear analogue, for example, reduced hydrodynamic radius and lower intrinsic viscosity, together with an atomic force microscopy (AFM) image of individual molecular knots, confirmed the formation of the resulting trefoil knotted polymer. The strategies employed here could be utilized to enrich the variety of available polymers with new architectures.
Topics: Copper; Magnetic Resonance Spectroscopy; Microscopy, Atomic Force; Polymers; Viscosity
PubMed: 25728998
DOI: 10.1002/anie.201411623 -
Macromolecular Rapid Communications Mar 2024A rare asymmetric bicyclic polymer containing different length of conjugated polyacetylene segments is synthesized by metathesis cyclopolymerization-mediated...
A rare asymmetric bicyclic polymer containing different length of conjugated polyacetylene segments is synthesized by metathesis cyclopolymerization-mediated blocking-cyclization technique. The size of each single ring differs from each other, and the unique cyclic polymer topology is controlled by adjusting the feed ratio of monofunctional monomer to catalyst. The topological difference between linear and bicyclic polymers is confirmed by several techniques, and the visualized morphology of asymmetric bicyclic polymer is directly observed without tedious post-modification process. The photoelectric and thermal properties of polymers are investigated. This work expands the pathway for the derivation of cyclic polymers, and such unique topological structure enriches the diversity of cyclic polymer classes.
Topics: Polyacetylene Polymer; Cyclization; Polymers; Polyynes; Catalysis
PubMed: 38227809
DOI: 10.1002/marc.202300628 -
Nano Letters Jul 2006A simple, yet innovative, method is presented for fabricating high-aspect-ratio polymer nanohairs (aspect ratio >20) on a solid substrate by sequential application of...
A simple, yet innovative, method is presented for fabricating high-aspect-ratio polymer nanohairs (aspect ratio >20) on a solid substrate by sequential application of molding and drawing of a thin polymer film. The polymer film was prepared by spin coating on a rigid or flexible substrate, and the temperature was raised above the polymer's glass transition while in conformal contact with a poly(urethane acrylate) mold having nanocavities. Consequently, capillary forces induced deformation of the polymer melt into the void spaces of the mold and the filled nanostructure was further elongated upon removal of the mold due to tailored adhesive force at the mold/polymer interface. The optimum value of the work of adhesion at the mold/polymer interface ranged from 0.9 to 1.1 times that at the substrate/polymer interface.
Topics: Capillary Action; Methacrylates; Microscopy, Electron, Scanning; Nanostructures; Polymers; Polyurethanes; Stress, Mechanical; Surface Properties; Temperature
PubMed: 16834440
DOI: 10.1021/nl061045m -
Macromolecular Rapid Communications Jan 2012
Topics: Green Chemistry Technology; Polymers
PubMed: 22213223
DOI: 10.1002/marc.201000789