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1.
Food Chem ; 334: 127345, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32712485

RESUMO

The development of a novel molecularly imprinted solid-phase extraction (MISPE) method for simultaneous preconcentration of imazapyr (IMP), imazapic (IMZ) and imazethapyr (IMT) with determination by HPLC-PAD (High performance liquid chromatography - photodiode-array detector) is proposed. The polymer synthesis was performed using imazethapyr as template molecule and 1-vinylimidazole as functional monomer. The method is based on preconcentration of 100.0 mL of sample through 200.0 mg of molecularly imprinted poly(vinylimidazole-TRIM) (MIP-1VN) at pH 4.0, followed by elution with 2.0 mL of MeOH:CH2Cl2:HAc (34:62:4, v/v). The range of analytical curve (0.29-200.0, 0.21-200.0 and 0.15-200.0 µg L-1), limits of detection (0.09, 0.06 and 0.04 µg L-1) and preconcentration factors (92, 96 and 98) determined for the herbicides, IMP, IMZ and IMT, respectively, were greatly superior when compared with those ones obtained with commercial adsorbents. The analytical method was successfully applied to spiked surface water and rice samples with good results of recovery values (86-107%).


Assuntos
Herbicidas/análise , Impressão Molecular/métodos , Oryza/química , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/análise , Cromatografia Líquida de Alta Pressão/métodos , Contaminação de Alimentos/análise , Imidazóis/análise , Imidazóis/síntese química , Imidazóis/química , Limite de Detecção , Niacina/análogos & derivados , Niacina/análise , Ácidos Nicotínicos/análise , Ácidos Nicotínicos/química , Polivinil/síntese química , Polivinil/química , Sementes/química , Extração em Fase Sólida/instrumentação
2.
Int J Biol Macromol ; 141: 792-808, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31505205

RESUMO

Fenugreek gum is modified using two different techniques: microwave-assisted and thermal synthesis technique of graft copolymerization. The synthesis was done by varying the concentration of acrylamide monomer and CAN initiator to get the best-grafted product. The physicochemical characteristics were determined by elemental analysis, FTIR spectroscopy, SEM, XRD, DSC, TGA, number-average molecular weight and intrinsic viscosity. All the grafted materials were tested by flocculation of different synthetic suspension media as well as river water. The process of deflocculation and refloccculation was also carried out and it was observed that refloccculation process has a good potential as the flocculation efficacy increased to a considerable extent. The flocculation efficacy increased from 92.05% to 94.32% upto a maximum of 95.98% in refloccculation process. The flocculation efficacy was found out to be 95.98%, 40.52% and 68.94% respectively kaolin, coal fine and iron ore suspensions. Flocculation was done in kaolin suspension of pH 2, 4, 7 and 10 and at different temperature range of 100, 250, 400 and 550C. It is expected that this material can be used as a highly efficient flocculant in future.


Assuntos
Resinas Acrílicas/química , Gomas Vegetais/química , Polivinil/química , Trigonella/química , Técnicas de Química Sintética , Floculação , Micro-Ondas , Estrutura Molecular , Polímeros/química , Polivinil/síntese química , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Termogravimetria , Difração de Raios X
3.
Carbohydr Polym ; 218: 154-162, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31221316

RESUMO

In this work, a novel poly(ionic liquid) with 1-vinyl-3-aminopropyl imidazolium cations was designed and used to modify cellulose aerogels via Schiff base reaction. The poly(ionic liquid) modified cellulose aerogels (PIL-CA) exhibited a well-interconnected porous structure and a high porosity of 86.2%. A zeta potential study showed the PIL-CA had a strong positive potential of more than 65 mV when its pH was below 6. Furthermore, after 350 min of adsorption experiments, the PIL-CA showed a superior adsorption capacity of 918 ± 8 mg g-1 towards bovine serum albumin (BSA) at pH 6 when its concentration was 1.5 mg m L-1. Finally, the PIL-CA was employed for the selective separation of target protein from a real serum sample, obtaining the BSA with high purity of over 98%.


Assuntos
Celulose/análogos & derivados , Géis/química , Imidazóis/química , Líquidos Iônicos/química , Polivinil/química , Soroalbumina Bovina/química , Adsorção , Animais , Bovinos , Celulose/síntese química , Géis/síntese química , Concentração de Íons de Hidrogênio , Imidazóis/síntese química , Líquidos Iônicos/síntese química , Polivinil/síntese química , Porosidade
4.
Molecules ; 24(9)2019 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-31067770

RESUMO

During the last number of years a variety of crystallization-driven self-assembly (CDSA) processes based on semicrystalline block copolymers have been developed to prepare a number of different nanomorphologies in solution (micelles). We herein present a convenient synthetic methodology combining: (i) The anionic polymerization of 2-vinylpyridine initiated by organolithium functionalized phosphane initiators; (ii) the cationic polymerization of iminophosphoranes initiated by -PR2Cl2; and (iii) a macromolecular nucleophilic substitution step, to prepare the novel block copolymers poly(bistrifluoroethoxy phosphazene)-b-poly(2-vinylpyridine) (PTFEP-b-P2VP), having semicrystalline PTFEP core forming blocks. The self-assembly of these materials in mixtures of THF (tetrahydrofuran) and 2-propanol (selective solvent to P2VP), lead to a variety of cylindrical micelles of different lengths depending on the amount of 2-propanol added. We demonstrated that the crystallization of the PTFEP at the core of the micelles is the main factor controlling the self-assembly processes. The presence of pyridinyl moieties at the corona of the micelles was exploited to stabilize gold nanoparticles (AuNPs).


Assuntos
Substâncias Macromoleculares/química , Nanopartículas Metálicas/química , Micelas , Polímeros/química , Cristalização , Ouro , Substâncias Macromoleculares/síntese química , Compostos Organofosforados/síntese química , Compostos Organofosforados/química , Tamanho da Partícula , Polimerização , Polímeros/síntese química , Polivinil/síntese química , Polivinil/química , Solventes/química
5.
Talanta ; 201: 496-502, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31122456

RESUMO

According to the molecular properties of non-steroidal anti-inflammatory drugs (NSADs), a new adsorbent for magnetic solid phase extraction (MSPE) was designed and synthesized. Triethyl-(4-vinylbenzyl)aminium chloride and 4-vinylbenzeneboronic acid were utilized as dual functional monomers to copolymerize with divinylbenzene on the surface of pre-modified Fe3O4 nanoparticles. The prepared magnetic adsorbent (Fe3O4@TCVA) was characterized by elemental analysis, Fourier transform infrared, scanning electron microscopy, transmission electron microscopy and vibrating sample magnetometer. Due to the abundant boronic acid, quaternary amine and phenyl groups, the Fe3O4@TCVA displayed satisfactory extraction performance for target NSADs (diclofenac acid, ibuprofen and mefenamic acid) by means of B-N coordination, anion-exchange, π-π and hydrophobic interactions. Under the optimized conditions, the Fe3O4@TCVA/MSPE was combined with high-performance liquid chromatography with diode array detection (HPLC-DAD) to sensitively analyze NSADs in water and human urine samples. Results indicated that the limits of detection for water and urine samples were in the ranges of 0.014-0.031 µg/L and 0.029-0.11 µg/L, respectively. The relative standard deviations for the intra-day and inter-day assay variability were below 10%. The applicability of the proposed Fe3O4@TCVA/MSPE-HPLC-DAD method was demonstrated by the successful extraction and quantification of trace levels of NSADs in real water and human urine samples. Satisfactory spiked recovery and reproducibility were achieved.


Assuntos
Anti-Inflamatórios não Esteroides/urina , Diclofenaco/urina , Ibuprofeno/urina , Ácido Mefenâmico/urina , Extração em Fase Sólida/métodos , Compostos de Vinila/química , Adsorção , Água Potável/análise , Humanos , Lagos/análise , Limite de Detecção , Nanopartículas de Magnetita/química , Polimerização , Polivinil/síntese química , Polivinil/química , Reprodutibilidade dos Testes , Cloreto de Sódio/química , Águas Residuárias/análise , Poluentes Químicos da Água/análise
6.
Colloids Surf B Biointerfaces ; 181: 134-142, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31128513

RESUMO

A simple and effective strategy to simultaneously enhance the permeability and antifouling properties of ethylene vinyl alcohol (EVAL) membrane was developed based on the bioinspired natural cleaner, cilia. Taking clue from the self-cleaning effect of cilia, supramolecular polyrotaxanes (PRs) with sliding and rotating cyclic molecules along linear chains were synthesized using azide-alkyne click chemistry. Cilia-like PRs were incorporated into EVAL matrix in the fabrication of modified EVAL membranes. Cilia-like structures protruding from the membrane surface have been observed by SEM, TEM and AFM. By imitating natural ciliary movements, these structures provided a proactive self-cleaning system to remove the foulants. The introduction of cilia-like PRs enhanced the surface roughness and hydrophilicity, and significantly enhanced permeability by 55.3% compared to raw EVAL membrane. Moreover, the membrane modified with cilia-like PRs showed an excellent antifouling property with a lower water flux decline (12.6%) and higher water flux recovery (94%) in dynamic fouling tests. Furthermore, this modified membrane develops the scope of bioinspired membranes, inspiring more attractive potential applications in self-cleaning materials, dynamic membranes and supramolecular machines.


Assuntos
Incrustação Biológica/prevenção & controle , Permeabilidade/efeitos dos fármacos , Polivinil/farmacologia , Alquinos/química , Azidas/química , Química Click , Interações Hidrofóbicas e Hidrofílicas , Tamanho da Partícula , Polivinil/síntese química , Polivinil/química , Propriedades de Superfície
7.
Anal Chim Acta ; 1058: 97-106, 2019 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-30851859

RESUMO

Owing to their multiscale pore size regimes and unique properties, the materials with hierarchically porous structures have become an important family of functional materials in recent years. They have been applied from energy conversion and storage, catalysis, separation to drug delivery, etc. The synthesis of them is difficult by the need to employ multiple templates and take complicated steps. Herein, we successfully prepared epoxy-functionalized hierarchically porous hybrid monoliths (HPHMs) with micro/meso/macro-structures in an easy way. Firstly, a bulk monolithic material was formed via free radical polymerization between polyhedral oligomeric vinylsilsesquioxanes (vinylPOSS) and allyl glycidyl ether (AGE) in the presence of polycaprolactone (PCL). Then PCL was degraded with hydrochloric acid solution, and the epoxy-functionalized HPHM was obtained. This approach was very simple and suitable for large-scale preparation. Hybrid monoliths with different specific surface area (from 5.4 to 636.7 m2/g) were prepared by adjusting the mole ratio of vinylPOSS to AGE and the content of PCL. The results of several characterization methods, including nitrogen adsorption/desorption measurements, scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP), showed that these materials contained not only micropores and mesopores but also macropores. The materials were further modified with penicillamine to be used as hydrophilic interaction chromatography (HILIC) adsorbents for enriching N-glycopeptides in IgG and serum protein tryptic digests. Up to 23 N-glycopeptides were identified from IgG digest, and 385 N-glycopeptides and 283 N-glycosylation sites were identified from human serum digest.


Assuntos
Cromatografia Líquida/métodos , Glicopeptídeos/sangue , Compostos de Organossilício/química , Polivinil/química , Adsorção , Animais , Bovinos , Compostos de Epóxi/química , Glicopeptídeos/química , Glicosilação , Humanos , Interações Hidrofóbicas e Hidrofílicas , Imunoglobulina G/química , Compostos de Organossilício/síntese química , Penicilamina/química , Poliésteres/síntese química , Poliésteres/química , Polimerização , Polivinil/síntese química , Porosidade , Proteólise , Soroalbumina Bovina/química , Tripsina/química
8.
J Colloid Interface Sci ; 543: 64-75, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30779994

RESUMO

This study proposed a novel strategy to improve performance of inherently hydrophobic poly(vinylidene fluoride) (PVDF) membrane. The proposed strategy combined radiation grafting of poly(acrylic acid) (PAA) and electroless nickel plating. After a 5 min plating by using this modification strategy, the water contact angle of the modified membrane decreased from 75.5° to 47.1°, and water content ratio increased from 61.4% to 109.9%. The modified PVDF-g-PAA-Ag@Ni membrane presented 100% flux recovery and reduced fouling propensity when filtrating 0.1 g/L sodium alginate (SA) solution. Moreover, involvement of silver in this strategy provided evident antibacterial activity of the modified membranes. The ease and high efficiency of this strategy point towards the potential widespread applications of this strategy and the modified membranes.


Assuntos
Resinas Acrílicas/química , Antibacterianos/síntese química , Níquel/química , Polivinil/síntese química , Antibacterianos/química , Interações Hidrofóbicas e Hidrofílicas , Tamanho da Partícula , Polivinil/química , Propriedades de Superfície
9.
J Pharm Biomed Anal ; 162: 117-123, 2019 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-30236819

RESUMO

A novel polymer monolith based on the dicationic crosslinker 3,3'-(hexane-1,6-diyl)bis(1-vinylimidazolium) bromide, the monomer 1-vinylimidazole and a ternary porogen mixture (1-propanol, decan-1-ol and water) was developed and optimized for capillary electrochromatography. This aim was accomplished by adjusting the composition of individual constituents in the polymerization mixture and monitored based on several relevant parameters (e.g. pore structure by scanning electron microscopy, generation of electroosmotic flow, or permeability of material). The ultimately selected composition yielded a monolithic phase which excellently resolved six methylxanthines (including caffeine, theobromine and theophylline) in 15 min. Key requirements concerning the utilized buffer were an acidic pH of 3 and the addition of 50% acetonitrile; additionally, a negative voltage (-25 kV) had to be applied during analyses. The proposed separation mechanism was mixed mode, i.e. the combination of electrostatic repulsion and hydrophobic interaction. Monolith fabrication as well as separation efficiency were found to be highly repeatable, the material was mechanically stable and useable for at least 150 injections. Thus the presented stationary phase is definitely a very promising option for CEC.


Assuntos
Eletrocromatografia Capilar/métodos , Reagentes para Ligações Cruzadas/síntese química , Imidazóis/síntese química , Polivinil/síntese química , Xantinas/análise , Estrutura Molecular , Polimerização , Pressão , Solventes/química , Fatores de Tempo
10.
Macromol Biosci ; 18(12): e1800335, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30408349

RESUMO

Surface topography has a profound effect on the development of the nervous system, such as neuronal differentiation and morphogenesis. While the interaction of neurons and the surface topography of their local environment is well characterized, the neuron-topography interaction during the regeneration process remains largely unknown. To address this question, an anisotropic surface topography resembling linear grooves made from poly(ethylene-vinyl acetate) (EVA), a soft and biocompatible polymer, using nanoimprinting, is established. It is found that neurons from both the central and peripheral nervous system can survive and grow on this grooved surface. Additionally, it is observed that axons but not dendrites specifically align with these grooves. Furthermore, it is demonstrated that neurons on the grooved surface are capable of regeneration after an on-site injury. More importantly, these injured neurons have an accelerated and enhanced regeneration. Together, the data demonstrate that this anisotropic topography guides axon growth and improves axon regeneration. This opens up the possibility to study the effect of surface topography on regenerating axons and has the potential to be developed into a medical device for treating peripheral nerve injuries.


Assuntos
Axônios/efeitos dos fármacos , Materiais Biocompatíveis/farmacologia , Regeneração Tecidual Guiada/métodos , Regeneração Nervosa/efeitos dos fármacos , Traumatismos dos Nervos Periféricos/terapia , Polietilenos/farmacologia , Polivinil/farmacologia , Animais , Anisotropia , Axônios/ultraestrutura , Materiais Biocompatíveis/síntese química , Materiais Biocompatíveis/química , Córtex Cerebral/citologia , Córtex Cerebral/efeitos dos fármacos , Gânglios Espinais/lesões , Gânglios Espinais/cirurgia , Camundongos , Camundongos Endogâmicos C57BL , Impressão Molecular/métodos , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Regeneração Nervosa/fisiologia , Neuritos/efeitos dos fármacos , Neuritos/ultraestrutura , Traumatismos dos Nervos Periféricos/patologia , Polietilenos/síntese química , Polietilenos/química , Polivinil/síntese química , Polivinil/química , Cultura Primária de Células , Ratos , Células Receptoras Sensoriais/efeitos dos fármacos , Células Receptoras Sensoriais/ultraestrutura
11.
Chem Pharm Bull (Tokyo) ; 66(10): 932-938, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30270240

RESUMO

It is well known that high-pressure carbon dioxide (CO2) lowers the glass transition temperature (Tg) of polymers. We therefore investigated whether Tg depression of high-pressure CO2 results in interparticle bridging of a polymer and the tablet characteristics that makes the manufacture of an orally disintegrating tablet (ODT) possible. Copolyvidone (Kollidon®) and polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus®) were examined and found to exhibit a large Tg depression. Placebo ODTs were prepared and hardness, disintegration rate, porosity, and change in thickness and appearance were evaluated before and after the high-pressure CO2 treatment. This enabled the establishment of the optimal conditions for pressure, temperature, and treatment time under pressure. Experimental results showed that it was possible to manufacture ODTs comprising Kollidon® as a water-soluble polymer with CO2 treatment under the suitable conditions such as temperature at 45°C, pressure lower than 8 MPa, and a treatment time shorter than 30 min, which is a new ODT manufacturing process called "Carbon Dioxide Assisted Tablet Formation Scheme" (CATS). In comparison to the conventional processes, which require high temperatures or humidity, CATS is expected to be applicable to drugs that are unstable at high temperature and humidity, and to functional drug particles used for bitter taste masking, sustained release, and other uses.


Assuntos
Dióxido de Carbono/química , Pressão , Comprimidos/administração & dosagem , Comprimidos/síntese química , Temperatura de Transição , Administração Oral , Composição de Medicamentos , Vidro/química , Tamanho da Partícula , Polietilenoglicóis/administração & dosagem , Polietilenoglicóis/síntese química , Polietilenoglicóis/química , Polímeros/administração & dosagem , Polímeros/síntese química , Polímeros/química , Polivinil/administração & dosagem , Polivinil/síntese química , Polivinil/química , Povidona/administração & dosagem , Povidona/síntese química , Povidona/química , Propriedades de Superfície , Comprimidos/química
12.
Macromol Rapid Commun ; 39(18): e1800414, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30085385

RESUMO

In this study, π-conjugated poly(arylenevinylene)s are synthesized via the Pd-catalyzed dehydrogenative direct alkenylation of polyfluoroarenes with diethenyl aromatic monomer. The introduction of a fluoro group promotes the cross-coupling reaction, and the formation of the undesired homocoupling byproduct is minimized by optimizing the reaction conditions. The polycondensation reactions lead to the formation of poly(arylenevinylene)s with a well-defined trans-configuration. The obtained polymers are evaluated as emitting materials for organic light-emitting diodes.


Assuntos
Alcenos/síntese química , Hidrocarbonetos Fluorados/química , Paládio/química , Polivinil/síntese química , Alcenos/química , Catálise , Hidrogenação , Estrutura Molecular , Polivinil/química
13.
AAPS PharmSciTech ; 19(6): 2620-2628, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29916195

RESUMO

Amorphous solid dispersions (ASDs) are inherently unstable because of high internal energy. Evaluating physical and chemical stability during the process and storage is essential. Numerous researches have demonstrated how polymers influence the drug precipitation and physical stability of ASDs, while the influence of polymers on the chemical stability of ASDs is often overlooked. Therefore, this study aimed to investigate the effect of polymers on the physical and chemical stability of spray-dried ASDs using dipyridamole (DP) as a model drug. Proper polymers were selected by assessing their abilities to inhibit drug recrystallization in supersaturated solutions. HPMC E5, Soluplus®, HPMCP-55, and HPMCAS-LP were shown to be effective stabilizers. The optimized formulations were further stored at a high temperature (60 °C) and high humidity (40 °C, 75% RH) for 2 months, and their physical and chemical stability was evaluated using polarizing optical microscopy, FTIR, HPLC, and mass spectrometry (MS). In general, crystallization was observed in all samples, which indicated the physical instability under stressed storage conditions. Also, it was noted that the polymers in ASDs rather than physical mixtures, induced a dramatic drug degradation after being exposed to a high temperature (HPMCP-55 > 80% and HPMCAS-LP > 50%) and high humidity (HPMCP-55 > 40% and HPMCAS-LP > 10%). The MS analysis further confirmed the degradation products, which might be generated from the reaction between dipyridamole and phthalic anhydride decomposed from HPMCP-55 and HPMCAS-LP. Overall, the exposure of ASDs to stressed conditions resulted in recrystallization and even the chemical degradation induced by polymers.


Assuntos
Dipiridamol/síntese química , Dipiridamol/farmacocinética , Polímeros/síntese química , Polímeros/farmacocinética , Cristalização/métodos , Composição de Medicamentos/métodos , Estabilidade de Medicamentos , Umidade , Metilcelulose/análogos & derivados , Metilcelulose/síntese química , Metilcelulose/farmacocinética , Inibidores de Fosfodiesterase/síntese química , Inibidores de Fosfodiesterase/farmacocinética , Polietilenoglicóis/síntese química , Polietilenoglicóis/farmacocinética , Polivinil/síntese química , Polivinil/farmacocinética , Solubilidade
14.
Colloids Surf B Biointerfaces ; 169: 494-501, 2018 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-29857249

RESUMO

Conjugated polymer nanoparticle systems have gained significant momentum in the bioimaging field on account of their biocompatibility and outstanding spectroscopic properties. Recently, new control procedures have spawned custom-built functional poly(p-phenylene vinylene) (PPV). These facilitate the one-pot synthesis of semiconducting polymer NPs with incorporated surface functional groups, an essential feature for advanced biomedical applications. In this work, nanoparticles (NPs) of different sizes are synthesized consisting of the statistical copolymer CPM-co-MDMO-PPV with monomer units 2-(5'-methoxycarbonylpentyloxy)-5-methoxy-1,4-phenylenevinylene (CPM-PPV) and poly(2-methoxy-5-(3',7'-dimethoxyoctyloxy)-1,4-phenylenevinylene) (MDMO-PPV). To monitor potential implications of switching from a commonly used homopolymer to copolymer system, MDMO-PPV NPs were prepared as a control. The versatile combination of the miniemulsion and solvent evaporation method allowed for an easy adaptation of the NP size. Decreasing the diameter of functional PPV-based NPs up to 20 nm did not significantly affect their optical properties nor the biocompatibility of the bioimaging probe, as cell viability never dropped below 90%. The quantum yield and molar extinction coefficient remained stable at values of 1-2% and 106 M-1 cm-1 respectively, indicating an excellent fluorescence brightness. However, a threshold was observed to which the size could be lowered without causing irreversible changes to the system. Cell uptake varied drastically depended on size and material choice, as switching from homo- to copolymer system and lowering the size significantly increased NP uptake. These results clearly demonstrate that adjusting the size of functional PPV-based NPs can be achieved easily to a lower limit of 20 nm without adversely affecting their performance in bioimaging applications.


Assuntos
Materiais Biocompatíveis/química , Corantes Fluorescentes/química , Nanopartículas/química , Polivinil/química , Materiais Biocompatíveis/síntese química , Materiais Biocompatíveis/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Relação Dose-Resposta a Droga , Fluorescência , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/farmacologia , Humanos , Hidrodinâmica , Cinética , Tamanho da Partícula , Polivinil/síntese química , Polivinil/farmacologia , Propriedades de Superfície
15.
J Pharm Sci ; 107(9): 2385-2398, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29752945

RESUMO

Solid dispersions of spironolactone with Soluplus® and polyvinylpyrrolidone were prepared by spray drying according to a mixture experimental design and evaluated for moisture content, particle size, drug solubility, crystallinity (powder X-ray diffraction and differential scanning calorimetry), and physicochemical interactions (Fourier-transform infrared spectroscopy, Raman). In vitro dissolution was evaluated for the spray dried product itself and after compression into tablets, and prediction models were derived using multiple linear regression analysis. The spray dried products consisted of amorphous drug, indicated by the absence of crystalline powder X-ray diffraction peaks. Amorphization and interactions impacted changes in the Fourier-transform infrared spectroscopy spectra in the ranges 2900-3000 cm-1 (C-H) and 1600-1800 cm-1 (C=O) and caused merging at 1690 cm-1 (C=O of lactone) and 1670 cm-1 (C=O of thioacetyl group). In the Raman spectra, amorphization and interactions resulted in disappearance of peak at 1690 cm-1 (C=O) and merging of peaks at 582 and 600 cm-1 (C-S). Hydrogen bonding between the thioacetyl group of the drug with the hydroxyl groups of Soluplus® caused marked suppression of the peak at 1190 cm-1 (R-C(=O)-S vibration). Amorphization and interactions resulted in improved solubility and dissolution which was greatest for drug/Soluplus® ratio 1:4 and was also demonstrated in the corresponding tablets.


Assuntos
Química Farmacêutica/métodos , Liberação Controlada de Fármacos , Polietilenoglicóis/síntese química , Polivinil/síntese química , Povidona/síntese química , Espironolactona/síntese química , Avaliação Pré-Clínica de Medicamentos/métodos , Excipientes Farmacêuticos/síntese química , Excipientes Farmacêuticos/farmacocinética , Polietilenoglicóis/farmacocinética , Polivinil/farmacocinética , Povidona/farmacocinética , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Espironolactona/farmacocinética , Comprimidos , Difração de Raios X/métodos
16.
Macromol Rapid Commun ; 39(9): e1800043, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29578265

RESUMO

The synthesis and self-assembly in thin-film configuration of linear ABC triblock terpolymer chains consisting of polystyrene (PS), poly(2-vinylpyridine) (P2VP), and polyisoprene (PI) are described. For that purpose, a hydroxyl-terminated PS-b-P2VP (45 kg mol-1 ) building block and a carboxyl-terminated PI (9 kg mol-1 ) are first separately prepared by anionic polymerization, and then are coupled via a Steglich esterification reaction. This quantitative and metal-free catalyst synthesis route reveals to be very interesting since functionalization and purification steps are straightforward, and well-defined terpolymers are produced. A solvent vapor annealing (SVA) process is used to promote the self-assembly of frustrated PS-b-P2VP-b-PI chains into a thin-film core-shell double gyroid (Q230 , space group: Ia3¯d) structure. As terraces are formed within PS-b-P2VP-b-PI thin films during the SVA process under a CHCl3 vapor, different plane orientations of the Q230 structure ((211), (110), (111), and (100)) are observed at the polymer-air interface depending on the film thickness.


Assuntos
Butadienos/química , Hemiterpenos/química , Nanoestruturas/química , Pentanos/química , Poliestirenos/química , Polivinil/química , Butadienos/síntese química , Hemiterpenos/síntese química , Tamanho da Partícula , Pentanos/síntese química , Polímeros/síntese química , Polímeros/química , Poliestirenos/síntese química , Polivinil/síntese química
17.
Macromol Rapid Commun ; 39(4)2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29193474

RESUMO

The first copper(0) mediated controlled radical polymerization (CRP) of methyl methacrylate (MMA) toward CF bonds onto poly(vinylidene fluoride) (PVDF) is reported with rather high activity. By avoiding the halogen exchange, Cu0 instead of CuI complexes utilized as catalyst is responsible for the significantly improved polymerization activity. Using FH decoupled nuclear magnetic resonance technique, the grafting sites onto PVDF are finely located. From this, detailed topologic information including the grafting density, average length of each side chain, along with the overall grafted content of PMMA, is detected by tracking the polymerization as a function of time. This work offers not only a facile CRP strategy based on inactive CF bonds but also a deep insight into the cleavage of F-bearing compounds in organic chemistry.


Assuntos
Cobre/química , Metilmetacrilato/química , Polivinil/química , Catálise , Transporte de Elétrons , Halogênios/química , Espectroscopia de Ressonância Magnética , Metilmetacrilato/síntese química , Polimerização , Polímeros/química , Polimetil Metacrilato/química , Polivinil/síntese química
18.
Macromol Rapid Commun ; 38(22)2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28980746

RESUMO

Block copolymer (BCP) self-assembly is a versatile technique in the preparation of polymeric aggregates with varieties of morphologies. However, its morphology library is limited. Here, the discovery of pincushion of tubules is reported for the first time, via BCP self-assembly of poly(4-vinylpyridine)-b-polystyrene (P4VP-b-PS) with very high molecular weight (500 kDa) and asymmetry (2 mol% P4VP). The investigation confirms the importance of core-forming block length on morphology control of BCP self-assemblies, especially with respect to tubular structures. The morphology landscape of tubular structures is successfully established, where dumbbell of tubule, tubule, loose clew of tubules, tight clew of tubules, and pincushion of tubules can be prepared by adjusting the core-forming block length. This work therefore expands the structure library of BCP self-assemblies and opens up a new avenue for the further applications of these tubular materials.


Assuntos
Poliestirenos/química , Polivinil/química , Microscopia Eletrônica de Transmissão , Peso Molecular , Nanoestruturas/química , Poliestirenos/síntese química , Polivinil/síntese química
19.
Macromol Rapid Commun ; 38(21)2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28921703

RESUMO

To address the challenge of metal contamination, a "graft from" approach via organocatalyzed atom transfer radical polymerization (O-ATRP) is developed to synthesize poly(vinylidene fluoride-co-chlorotrifluoroethylene) (P(VDF-co-CTFE)) graft copolymers. N-phenylphenothiazine is utilized as a model organic photoredox catalyst for catalyzing the (co)polymerization of methyl methacrylate (MMA), methacrylate (MA), and n-butyl acrylate (BA). By employing this technique, high temporal control of polymerization and graft content are achieved. A series of P(VDF-co-CTFE)-g-PMMA, P(VDF-co-CTFE)-g-PMA, and P(VDF-co-CTFE)-g-PBA is prepared under mild conditions. The resultant graft copolymer can be used as macroinitiator to re-initiate O-ATRP to synthesize P(VDF-co-CTFE)-g-(PMMA-b-PMA), which might exhibit the potential application as novel dielectric material.


Assuntos
Polimerização , Polivinil/química , Catálise , Cromatografia em Gel , Polivinil/síntese química , Espectroscopia de Prótons por Ressonância Magnética
20.
J Am Chem Soc ; 139(29): 9876-9884, 2017 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-28700228

RESUMO

Recent developments in scanning probe block copolymer lithography (SPBCL) enable the confinement of multiple metal precursors in a polymer nanoreactor and their subsequent transformation into a single multimetallic heterostructured nanoparticle through thermal annealing. However, the process by which multimetallic nanoparticles form in SPBCL-patterned nanoreactors remains unclear. Here, we utilize the combination of PEO-b-P2VP and Au, Ag, and Cu salts as a model three-component system to investigate this process. The data suggest that the formation of single-component Au, Ag, or Cu nanoparticles within polymer nanoreactors consists of two stages: (I) nucleation, growth, and coarsening of the particles to yield a single particle in each reactor; (II) continued particle growth by depletion of the remaining precursor in the reactor until the particle reaches a stable size. Also, different aggregation rates are observed for single-component particle formation (Au > Ag > Cu). This behavior is also observed for two-component systems, where nucleation sites have greater Au content than the other metals. This information can be used to trap nanoparticles with kinetic structures. High-temperature treatment ultimately facilitates the structural evolution of the kinetic particle into a particle with a fixed structure. Therefore, with multicomponent systems, a third stage that involves elemental redistribution within the particle must be part of the description of the synthetic process. This work not only provides a glimpse at the mechanism underlying multicomponent nanoparticle formation in SPBCL-generated nanoreactors but also illustrates, for the first time, the utility of SPBCL as a platform for controlling the architectural evolution of multimetallic nanoparticles in general.


Assuntos
Cobre/química , Ouro/química , Nanopartículas/química , Polietilenoglicóis/química , Polivinil/química , Prata/química , Microscopia Eletrônica de Transmissão e Varredura , Estrutura Molecular , Tamanho da Partícula , Polietilenoglicóis/síntese química , Polivinil/síntese química , Sais/química , Propriedades de Superfície
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