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1.
Food Chem ; 313: 125926, 2020 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-31945703

RESUMO

This study investigates whether the formation of monochloropropane diol fatty acid esters (MCPDE) can be mitigated by removing the residual sediments from vegetable oils. Settling and centrifugation were conducted in crude sunflower and palm oil and the purified oils and their sediment-rich fractions were heated and analyzed for their MCPDE content. Increased MCPDE levels by factors of x2 to x6 were found in the sediment-rich fractions of settled sunflower oils compared to the sediment-free oil. The sediment-containing fraction could be however purified by ultracentrifugation resulting in the mitigation of MCPDE levels by a factor of 10. The effect of residual sediment on the MCPDE formation was also confirmed in the case of palm oil showing x2 to x10 more MCPDE formation in the sediment containing fractions compared to the purified oil. These results confirm that the mechanical removal of the trace sediments from crude vegetable oils results in reduced MCPDE levels.


Assuntos
Ésteres/análise , Óleos Vegetais/química , Propilenoglicóis/química , Cromatografia Líquida de Alta Pressão , Ésteres/química , Espectrometria de Massas , Óleo de Palmeira/química , Óleo de Girassol/química , Temperatura , Ultracentrifugação
2.
Polim Med ; 49(1): 35-43, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31769938

RESUMO

BACKGROUND: Poorly water-soluble drugs do not dissolve well in aqueous-based gastrointestinal fluid; therefore, they are not well absorbed. Thus, employing a suitable solubility enhancing technique is necessary for such a drug. Drug/HP­ß­CD complexation is a promising way to improve solubility and dissolution of a poorly water-soluble drug. Levodropropizine was used as a model drug in this study. OBJECTIVES: The purpose of this research was to enhance the aqueous solubility and dissolution rate of levodropropizine by employing the inclusion complexation technique. MATERIAL AND METHODS: A microparticle formulation was prepared from levodropropizine and hydroxypropyl-ß-cyclodextrin (HP­ß­CD) in a 1:1 molar ratio through the spray-drying technique. The host-guest relationship between levodropropizine and HP­ß­CD was also investigated using the molecular docking computational methodology. The aqueous solubility and dissolution rate of levodropropizine in formulations were assessed and compared with those of the drug alone. X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) were applied for the solid-state characterization of the prepared samples. RESULTS: According to the research outcomes, the levodropropizine/HP­ß­CD formulation had enhanced the aqueous solubility (351.12 ±13.26 vs 92.76 ±5.00 mg/mL) and dissolution rate (97.83 ±3.36 vs 3.12 ±1.76% in 10 min) of levodropropizine, compared to the plain drug powder. The levodropropizine/ HP­ß­CD formulation had converted the crystalline drug into its amorphous counterpart. Furthermore, no covalent interaction was found to exist between levodropropizine and HP­ß­CD. The spray-dried particles were discrete. Each particle had a shriveled appearance. CONCLUSIONS: The levodropropizine/HP­ß­CD formulation is, therefore, recommended for the more effective administration of levodropropizine through the oral route.


Assuntos
Propilenoglicóis , beta-Ciclodextrinas , 2-Hidroxipropil-beta-Ciclodextrina , Varredura Diferencial de Calorimetria , Microscopia Eletrônica de Varredura , Simulação de Acoplamento Molecular , Propilenoglicóis/química , Propilenoglicóis/farmacologia , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , beta-Ciclodextrinas/química , beta-Ciclodextrinas/farmacologia
3.
Chem Asian J ; 14(24): 4837-4846, 2019 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-31756283

RESUMO

Three-dimensional (3D) scaffolds formed from natural biopolymers gelatin and chitosan that are chemically modified by galactose have shown improved hepatocyte adhesion, spheroid geometry and functions of the hepatocytes. Galactose specifically binds to the hepatocytes via the asialoglycoprotein receptor (ASGPR) and an increase in galactose density further improves the hepatocyte proliferation and functions. In this work, we aimed to increase the galactose density within the biopolymeric scaffold by physically blending the biopolymers chitosan and gelatin with an amphiphlic ß-galactose polypeptide (PPO-GP). PPO-GP, is a di-block copolymer with PPO and ß-galactose polypeptide, exhibits lower critical solution temperature and is entrapped within the scaffold through hydrophobic interactions. The uniform distribution of PPO-GP within the scaffold was confirmed by fluorescence microscopy. SEM and mechanical testing of the hybrid scaffolds indicated pore size, inter connectivity and compression modulus similar to the scaffolds made from 100 % biopolymer. The presence of the PPO-GP on the surface of the scaffold was tested monitoring the interaction of an analogous mannose containing PPO-GP scaffold and the mannose binding lectin Con-A. In vitro cell culture experiments with HepG2 cells were performed on GLN-GP and CTS-GP and their cellular response was compared with GLN and CTS scaffolds for a period of seven days. Within three days of culture the Hep G2 cells formed multicellular spheroids on GLN-GP and CTS-GP more efficiently than on the GLN and CTS scaffolds. The multicellular spheroids were also found to infiltrate more in GLN-GP and CTS-GP scaffolds and able to maintain their round morphology as observed by live/dead and SEM imaging.


Assuntos
Quitosana/química , Gelatina/química , Glicoproteínas/química , Hepatócitos/metabolismo , Polímeros/química , Propilenoglicóis/química , Tecidos Suporte/química , Animais , Módulo de Elasticidade , Galactosídeos/química , Células Hep G2 , Humanos , Hidrogéis/síntese química , Hidrogéis/química , Esferoides Celulares/metabolismo , Suínos , Engenharia Tecidual/métodos
4.
Int J Pharm ; 570: 118683, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31513869

RESUMO

The objective of this study was to formulate an anticancer preclinical lead, IIIM-290, loaded in solid dispersions to enhance its solubility, dissolution, and oral pharmacokinetics. IIIM-290 is an in-house preclinical anticancer lead prepared by semisynthetic modification of the natural product rohitukine. It is an orally bioavailable Cdk inhibitor showing efficacy in xenograft models of pancreatic, colon and leukemia cancer. It demonstrated in vivo efficacy at a relatively higher dose owing to its poor aqueous solubility (~8.6 µg/mL). Binary and ternary solid dispersions containing PVP K-30, xanthan gum, and PEG-PPG-PEG were selected after solubility screening of various hydrophilic polymers. Several formulations with varying ratios of polymers, alone and in combination, were prepared and investigated for their effects on the solubility enhancement of IIIM-290. The binary solid dispersion VKB-SD75, prepared with PVP K-30 at the ratio of 1:4 w/w, was identified as the optimized composition that displayed 17-fold improvement in the aqueous solubility of IIIM-290. VKB-SD75 was scaled up to a 100-g scale. IIIM-290 and VKB-SD75 were evaluated for DSC, p-XRD, FTIR, 1H NMR, SEM, in vitro dissolution, and oral pharmacokinetics, as well as for in vivo anticancer activity in the Ehrlich solid tumor model. The oral administration of VKB-SD75 in BALB/c mice resulted in a 1.9-fold improvement in plasma exposure. These findings also correlated well when the formulation was administered to mice in the Ehrlich solid tumor model. The newly developed solid dispersion is expected to reduce the dose of IIIM-290 by ~40-50% in preclinical and clinical studies.


Assuntos
Antineoplásicos/química , Administração Oral , Animais , Antineoplásicos/metabolismo , Disponibilidade Biológica , Varredura Diferencial de Calorimetria/métodos , Química Farmacêutica/métodos , Portadores de Fármacos/química , Avaliação Pré-Clínica de Medicamentos/métodos , Interações Hidrofóbicas e Hidrofílicas , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Polietilenoglicóis/química , Polímeros/química , Propilenoglicóis/química , Solubilidade/efeitos dos fármacos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos
5.
Int J Pharm ; 569: 118624, 2019 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-31419461

RESUMO

Nanostructured lipid carriers (NLC) and nanoemulsions (NE) are colloid carriers which could improve dermal delivery of tacrolimus. The aims of this study were to evaluate effects of different formulation and process parameters on physicochemical characteristics and stability of lecithin-based NLC with glyceryl palmitostearate as solid and propylene glycol monocaprylate as liquid lipid and to compare the influence of different inner structure of tacrolimus-loaded NLC and corresponding NE on physicochemical characteristics, stability, entrapment efficiency, in vitro drug release and overall skin performance. Solid/liquid lipid ratio, total amount of lipids, homogenization pressure and cooling after the preparation were identified as critical variables in NLC development. Moreover, tacrolimus-loaded NLC emerged as more stabile carrier than NE. Differential stripping performed on porcine ear skin revealed significantly higher tacrolimus amount in stratum corneum from nanocarriers compared to referent ointment (Protopic®). Similarly the highest amount of tacrolimus in hair follicles was obtained using NLC (268.54 ±â€¯92.38 ng/cm2), followed by NE (128.17 ±â€¯48.87 ng/cm2) and Protopic® (77.61 ±â€¯43.25 ng/cm2). Contrary, the highest permeation rate through full-thickness porcine ear skin was observed for Protopic®, implying that the selection of experimental setup is critical for reliable skin performance assessment. Overall, developed NLC could be suggested as promising carrier in a form of lotion for tacrolimus dermal delivery.


Assuntos
Portadores de Fármacos/administração & dosagem , Imunossupressores/administração & dosagem , Lecitinas/administração & dosagem , Nanoestruturas/administração & dosagem , Tacrolimo/administração & dosagem , Administração Cutânea , Animais , Caprilatos/administração & dosagem , Caprilatos/química , Portadores de Fármacos/química , Composição de Medicamentos , Liberação Controlada de Fármacos , Emulsões , Imunossupressores/química , Lecitinas/química , Lipídeos/administração & dosagem , Lipídeos/química , Nanoestruturas/química , Pomadas , Propilenoglicóis/administração & dosagem , Propilenoglicóis/química , Pele/metabolismo , Absorção Cutânea , Suínos , Tacrolimo/química
6.
Drug Dev Ind Pharm ; 45(10): 1624-1634, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31353967

RESUMO

Nano-emulgel has become one of the most significant controlled release systems, which has the advantages of both gels and nano-emulsions. This work aims at the formulation of nasal nano-emulgel for resveratrol, employing carbopol 934 and poloxamer 407 as the gelling agents. The optimum nano-emulsion was determined through further characterization of the selected system. The nasal nano-emulgel was prepared and tested for the in vitro release, the release kinetics, FTIR, ex vivo permeation, nasal mucosa toxicity, and in vivo pharmacokinetic study. The optimum nano-emulsion consisted of Tween 20, Capryol 90, and Transcutol at a ratio of (54.26: 23.81: 21.93%v/v), and it exhibited transmittance of 100%, resveratrol solubility of 159.9 ± 6.4 mg/mL, globule size of 30.65 nm. The in vitro resveratrol released from nano-emulsion and nasal nano-emulgel was 96.17 ± 4.43% and 78.53 ± 4.7%, respectively. Ex vivo permeation was sustained during 12 h up to 63.95 ± 4.7%. The histopathological study demonstrated that the formula is safe and tolerable to the nasal mucosa. Cmax and AUC (0-∞) of resveratrol obtained after nasal administration of nasal nano-emulgel was 2.23 and 8.05 times, respectively. Similarly, Tmax was increased up to 3.67 ± 0.82 h. The optimized nasal nano-emulgel established intranasal safety and bioavailability enhancement so it is considered as a well-designed system to target the brain.


Assuntos
Emulsões/química , Emulsões/farmacocinética , Géis/química , Géis/farmacocinética , Mucosa Nasal/metabolismo , Resveratrol/química , Resveratrol/farmacocinética , Administração Intranasal/métodos , Animais , Disponibilidade Biológica , Química Farmacêutica/métodos , Sistemas de Liberação de Medicamentos/métodos , Masculino , Poloxâmero/química , Polímeros/química , Polissorbatos/química , Propilenoglicóis/química , Ratos , Ratos Wistar , Solubilidade/efeitos dos fármacos
7.
N Biotechnol ; 53: 81-89, 2019 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-31302257

RESUMO

Crude glycerol is an excellent carbon source for bacterial production systems. Bacterial fermentation often generates by-products that can offer an additional carbon pool to improve the product profile for optimal valorization. In this study, the properties of two phylogenetically distinct bacteria, Acinetobacter baylyi ADP1 and Clostridium butyricum, were coupled in a one-pot batch process to co-produce 1,3 propanediol (PDO) and long-chain alkyl esters (wax esters, WEs) from crude glycerol. In the process, A. baylyi deoxidized the growth medium allowing glycerol fermentation and PDO production by C. butyricum. Reaeration of the co-cultivations enabled A. baylyi to metabolize the fermentation by-products, acetate and butyrate, and synthesize intracellular WEs. To improve PDO production and A. baylyi growth, carbon and macronutrients in the growth medium were screened and optimized using Plackett-Burman and Box-Behnken models. The validation experiment revealed a good correlation between the observed and predicted values. The salting-out method recovered 89.5% PDO from the fermentation broth and in vacuo extraction resulted in a PDO content of 5.3 g L-1. Nuclear magnetic resonance revealed a WE content and yield of 34.4 ±â€¯1.4 mg L-1 and 34.2 ±â€¯3.2 mg WE g-1 dry cell weight, respectively. A molar yield of 0.65 mol PDO mol-1 and 0.62 µmol WE mol-1 crude glycerol was achieved with the synthetic consortium. This work emphasizes the strength of response surface methodology in improving production processes from the mutualistic association of divergent bacterial species in consortium. The co-production of PDO and WEs from crude glycerol is demonstrated for the first time in this study.


Assuntos
Acinetobacter/química , Clostridium butyricum/química , Ésteres/metabolismo , Glicerol/química , Propilenoglicóis/metabolismo , Acinetobacter/metabolismo , Clostridium butyricum/metabolismo , Ésteres/química , Fermentação , Glicerol/metabolismo , Propilenoglicóis/química
8.
Carbohydr Res ; 481: 23-30, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31220628

RESUMO

We synthesized phenylacetylenes containing ß-lactoside, ß-cellobioside, or ß-maltoside, and polymerized them to produce the corresponding poly (phenylacetylene)s. In these poly (phenylacetylene)s, the pendent carbohydrates were tethered to the mainchains by serinol spacers. Because similar glycosyl serinol units are found in the natural glycosphingolipids in cell membranes, the densely packed carbohydrate clusters along the poly (phenylacetylene) mainchains act as molecular mimics of cell surface glycoclusters. We analyzed the conformation of the glycosylated poly (phenylacetylene)s using circular dichroism spectroscopy, and found that the spatial carbohydrate packing within the glycoclusters changed on the addition of salts.


Assuntos
Acetileno/análogos & derivados , Conformação Molecular , Propanolaminas/química , Propilenoglicóis/química , Açúcares/química , Acetileno/síntese química , Acetileno/química , Técnicas de Química Sintética , Glicosilação , Simulação de Dinâmica Molecular , Polimerização , Sais/química , Estereoisomerismo , Água/química
9.
Int J Pharm ; 565: 233-241, 2019 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-31075439

RESUMO

We propose a polymeric nanovehicles (PNVs)-based enhanced transdermal delivery platform. A technical advance can be found in that delivery efficiency is significantly enhanced by effective adhesion of PNVs to the cell membrane, which is characterized noninvasively by using a confocal laser scanning microscopy (CLSM)-based skin visualization technique. To this end, the PNVs with a soft core phase were fabricated through co-assembly of two amphiphilic triblock copolymers, poly(ethylene oxide)-b-poly(ε-caprolactone)-b-poly(ethylene oxide) (PEO-b-PCL-b-PEO) and poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-b-PPO-b-PEO). The softness of PNVs was tuned successfully, while maintaining the particle size at ∼110 nm, by incorporation of PEO-b-PPO-b-PEO into the PNVs to a volume fraction of 0.3. Through an ex vivo skin penetration test, we showed that transactivating transcriptional activator (TAT)-decorated soft PNVs could not only exert strong adhesion to skin but also increase cellular uptake, leading to a transdermal delivery efficiency that is twice that of a hard PNV control. Moreover, CLSM-based noninvasive visualization of a fluorescent drug probe in the skin showed that the adhesiveness and softness of the PNVs contributed directly to the enhancement of transdermal delivery.


Assuntos
Membrana Celular , Sistemas de Liberação de Medicamentos , Fragmentos de Peptídeos/administração & dosagem , Poliésteres/administração & dosagem , Polietilenoglicóis/administração & dosagem , Propilenoglicóis/administração & dosagem , Produtos do Gene tat do Vírus da Imunodeficiência Humana/administração & dosagem , Adesividade , Administração Cutânea , Animais , Linhagem Celular Tumoral , Humanos , Microscopia Confocal , Tamanho da Partícula , Poliésteres/química , Polietilenoglicóis/química , Propilenoglicóis/química , Pele/metabolismo , Absorção Cutânea , Suínos
10.
Eur J Pharm Sci ; 135: 51-59, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31071439

RESUMO

Nanostructured lipid carriers (NLC) belong to youngest lipid-based nanocarrier class and they have gained increasing attention over the last ten years. NLCs are composed of a mixture of solid and liquid lipids, which solubilizes the active pharmaceutical ingredient, stabilized by a surfactant. The miscibility of the lipid excipients and structural changes (polymorphism) play an important role in the stability of the formulation and are not easily predicted in the early pharmaceutical development. Even when the excipients are macroscopically miscible, microscopic heterogeneities can result in phase separation during storage, which is only detected after several months of stability studies. In this sense, this work aimed to evaluate the miscibility and the presence of polymorphism in lipid mixtures containing synthetic (cetyl palmitate, Capryol 90®, Dhaykol 6040 LW®, Precirol ATO5® and myristyl myristate) and natural (beeswax, cocoa and shea butters, copaiba, sweet almond, sesame and coconut oils) excipients using Raman mapping and multivariate curve resolution - alternating least squares (MCR-ALS) method. The results were correlated to the macroscopic stability of the formulations. Chemical maps constructed for each excipient allowed the direct comparison among formulations, using standard deviation of the histograms and the Distributional Homogeneity Index (DHI). Lipid mixtures of cetyl palmitate/Capryol®; cetyl palmitate/Dhaykol®; myristyl myristate/Dhaykol® and myristyl myristate/coconut oil presented a single histogram distribution and were stable. The sample with Precirol®/Capryol® was not stable, although the histogram distribution was narrower than the samples with cetyl palmitate, indicating that miscibility was not the factor responsible for the instability. Structural changes before and after melting were identified for cocoa butter and shea butter, but not in the beeswax. Beeswax + copaiba oil sample was very homogenous, without polymorphism and stable over 6 months. Shea butter was also homogeneous and, in spite of the polymorphism, was stable. Formulations with cocoa butter presented a wider histogram distribution and were unstable. This paper showed that, besides the miscibility evaluation, Raman imaging could also identify the polymorphism of the lipids, two major issues in lipid-based formulation development that could help guide the developer understand the stability of the NLC formulations.


Assuntos
Portadores de Fármacos/química , Lipídeos/química , Nanopartículas/química , Diglicerídeos/química , Composição de Medicamentos , Estabilidade de Medicamentos , Armazenamento de Medicamentos , Excipientes/química , Análise Multivariada , Miristatos/química , Palmitatos/química , Tamanho da Partícula , Óleos Vegetais/química , Polímeros/química , Propilenoglicóis/química , Solubilidade , Análise Espectral Raman , Tensoativos/química , Ceras/química
11.
Chemosphere ; 228: 735-743, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31071560

RESUMO

This study investigated the oxidative debromination of 2,2-bis(bromomethyl)-1,3-propanediol (BBMP), a widely used brominated flame retardant, and the corresponding formation of brominated by-products by the UV/persulfate process. The debromination of BBMP by the UV/persulfate process was primarily driven by sulfate radicals (SO4-) at pHs 4.0-6.0 and hydroxyl radicals (HO) at pHs 9.0-12.0. The debromination rate increased with increasing pH from 4.0 to 9.0 and remained the same at pHs 9.0 and 12.0. Bromate was formed through the oxidation of bromide released from BBMP mainly by SO4-, with free bromine as a key intermediate. Bromate formation increased with increasing pH from 4.0 to 6.0, while it remarkably decreased with increasing pH from 6.0 to 12.0. This was mainly due to the transformation of SO4- to HO and also the quenching of bromine atoms that were the key intermediate for the formation of free bromine, by hydroxyl ions at the alkaline pH. In addition, the oxidative debromination of BBMP resulted in a significant decrease in the concentrations of total organic bromine, but the formation of brominated acetic acids and unknown brominated organic by-products. The concentrations of brominated organic by-products firstly increased and then decreased with prolonged reaction time. Also, the formation of brominated organic by-products and genotoxicity at pH 9.0 were much lower than that at pH 6.0. In this study, we propose that the UV/persulfate process under mildly alkaline conditions not only debrominates BBMP efficiently but also eliminates the formation of bromate and brominated organic by-products and genotoxicity.


Assuntos
Retardadores de Chama , Propilenoglicóis/química , Poluentes Químicos da Água/química , Bromatos/química , Brometos/química , Bromo/química , Retardadores de Chama/efeitos da radiação , Halogenação , Radical Hidroxila , Oxirredução , Propilenoglicóis/efeitos da radiação , Sulfatos/química , Raios Ultravioleta , Poluentes Químicos da Água/efeitos da radiação
12.
Adv Mater ; 31(27): e1808233, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31081156

RESUMO

Microcapsules are often used as individually dispersed carriers of active ingredients to prolong their shelf life or to protect premature reactions with substances contained in the surrounding. This study goes beyond this application and employs microcapsules as principal building blocks of macroscopic 3D materials with well-defined granular structures. To achieve this goal and inspired by nature, capsules are fabricated from block-copolymer surfactants that are functionalized with catechols, a metal-coordinating motive. These surfactants self-assemble at the surface of emulsion drops where they are ionically cross-linked to form viscoelastic capsules that display a low permeability even toward small encapsulants. It is demonstrated that the combination of the mechanical strength, flexibility, and stickiness of the capsules enables their additive manufacturing into macroscopic granular structures. Thereby, they open up new opportunities for 3D printing of soft, self-healing materials composed of individual compartments that can be functionalized with different types of spatially separated reagents.


Assuntos
Cápsulas/química , Tensoativos/química , Catecóis/química , Complexos de Coordenação/química , Reagentes para Ligações Cruzadas/química , Fluorcarbonetos/química , Ferro/química , Fenômenos Mecânicos , Permeabilidade , Polímeros/química , Impressão Tridimensional , Propilenoglicóis/química
13.
Molecules ; 24(8)2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30999658

RESUMO

The objective of this study is to assess the efficiency of biobased carbonization agent in intumescent formulations (IFRs) to examine the flame retardant properties of polylactic acid (PLA) composites and to investigate their melt-spinnability. We used phosphorous-based halogen free flame retardant (FR) and kraft lignin (KL) as bio-based carbonization agent. After melt compounding and molding into sheets by hot pressing various fire related characteristics of IFR composites were inspected and were characterized by different characterization methods. It was fascinating to discover that the introduction of 5-20 wt% FR increased the limiting oxygen index (LOI) of PLA composites from 20.1% to 23.2-33.5%. The addition of KL with content of 3-5 wt% further increased the LOI up to 36.6-37.8% and also endowed PLA/FR/KL composites with improved anti-dripping properties. Cone calorimetry revealed a 50% reduction in the peak heat release rate of the IFR composites in comparison to 100% PLA and confirmed the development of an intumescent char structure containing residue up to 40%. For comparative study, IFR composites containing pentaerythritol (PER) as a carbonization agent were also prepared and their FR properties were compared. IFR composites were melt spun and mechanical properties of multifilament yarns were tested. The analysis of char residues by energy dispersive X-ray spectrometry (EDS) and SEM images confirmed that PLA/FR/KL composites developed a thicker and more homogeneous char layer with better flame retardant properties confirming that the fire properties of PLA can be enhanced by using KL as a carbonization agent.


Assuntos
Retardadores de Chama/análise , Lignina/química , Poliésteres/química , Propilenoglicóis/química
14.
Methods Mol Biol ; 1973: 261-279, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31016708

RESUMO

Molecular beacons composed of the artificial serinol nucleic acid (SNA) have demonstrated utility as novel fluorescence probes for visualization of RNA in fixed cells using both conventional fluorescence in situ hybridization (FISH) and wash-free FISH protocols. The SNA molecular beacons have higher affinity for target RNA and greater sensitivity than molecular beacons composed of DNA. Here we describe facile synthesis of the SNA using a conventional DNA synthesizer and protocols for purification by PAGE and HPLC as well as methods for use of the SNA molecular beacon in FISH.


Assuntos
Corantes Fluorescentes/química , Hibridização in Situ Fluorescente/métodos , Ácidos Nucleicos/química , Sondas de Oligonucleotídeos/química , Propanolaminas/química , Propilenoglicóis/química , RNA/análise , Hibridização de Ácido Nucleico
15.
J Colloid Interface Sci ; 544: 217-229, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30849619

RESUMO

Poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) (F127) hydrogels have been used to deliver nitric oxide (NO) topically in biomedical applications. Here, the effect of F127 microenvironments on the photochemical NO release from S-nitrosoglutathione (GSNO) was investigated in F127 solutions 7.6 wt% 15 wt% and 22.5 wt% at 15 °C and 37 °C. Small-angle X-ray Scattering (SAXS) and Differential Scanning Calorimetry (DSC) measurements, along with proton Nuclear Magnetic Resonance (1H NMR) spectral shifts and T2 relaxation data at six different concentration-temperature conditions, allowed identifying F127 microphases characterized by: a sol phase of unimers; micelles in non-defined periodic order, and a gel phase of cubic packed micelles. Kinetic measurements showed that GSNO photodecompositon proceeds faster in micellized F127 where GSNO is segregated to the intermicellar microenvironment. Real time kinetic monitoring of NO release and T2 relaxation profiles showed that NO is preferentially partitioned into the hydrophobic PPO cores of the F127 micelles, with the consequent decrease in its rate of release to the gas phase. These results show that F127 microphases affect both the kinetics of GSNO photodecomposition and the rate of NO escape and can be used to modulate the photochemical NO delivery from F127/GSNO solutions.


Assuntos
Hidrogéis/química , Óxido Nítrico/química , Poloxâmero/química , Polietilenoglicóis/química , Polímeros/química , Propilenoglicóis/química , S-Nitrosoglutationa/química , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Cinética , Micelas , Processos Fotoquímicos , Temperatura
16.
Macromol Rapid Commun ; 40(9): e1900020, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30821874

RESUMO

The anionic ring opening polymerizations of ethylene oxide (EO) and propylene oxide (PO) are performed by using 1,3,5-triethanol hexahydro-1,3,5-triazine (TrAz) as a "sacrificial" trifunctional initiator. Well-defined three-arm star polymers are obtained with a narrow molecular weight distribution (M w /M n < 1.1). Molecular weights range from 3-15 kg mol-1 . Since these star polymers possess an acid-labile hexahydro-triazine core, acidic hydrolysis leads to cleavage of the arms. This gives access to well-defined α-amino-ω-hydroxyl heterobifunctional poly(ethylene glycol) (PEG) and poly(propylene oxide) (PPO) in the molecular weight range of 1-5 kg mol-1 and low dispersity M w /M n < 1.1. The α,ω-heterobifunctional polyethers are valuable structures for bioconjugation. Furthermore, an acid-labile triazine star polymer is directly used as a polyol component for the synthesis of a polyurethane network, which is stable under ambient conditions but degrades rapidly under acidic conditions.


Assuntos
Polímeros/química , Propilenoglicóis/química , Compostos de Epóxi/química , Óxido de Etileno/química , Peso Molecular , Polimerização , Triazinas/química
17.
Mater Sci Eng C Mater Biol Appl ; 98: 293-299, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30813030

RESUMO

Over the past several years, the biomedical applications of fluorescent organic nanoparticles (FONs) with aggregation-induced emission (AIE) feature have been extensively explored because the AIE-active FONs could effectively overcome the aggregation caused quenching (ACQ) effect of FONs based on conventional organic dyes. The development of novel methods for synthesis of AIE-active FONs plays a centre role for their biomedical applications. In this work, we reported a facile one-step thiol-ene click reaction for fabrication of AIE-active FONs through conjugation of acrylated PEG and AIE-active tetraphenylethylene (TPE) with two ene bonds using pentaerythritol tetra(3-mercaptopropionate) as the linkage. The successful synthesis of TPE containing AIE-active copolymers was evidenced by various characterization techniques. The particle size and fluorescence properties of the resultant TPE-S-PEG copolymers were evaluated by transmission electronic microscopy and fluorescence spectroscopy. Moreover, the cell viability and cell uptake behavior was also examined to evaluate their potential for biological imaging. We demonstrated that the cross-linked TPE-S-PEG show small size, high water dispersibility, low cytotoxicity and strong fluorescence for tracing. All of these advantages endow the TPE-S-PEG FONs great potential for biological imaging applications. Furthermore, this novel click reaction can take place under mild experimental conditions with high efficiency. It could be also further expanded for preparation of multifunctional AIE-active materials due to the universality of the thiol-ene click reaction and good precursor applicapability. Taken together, we have developed a novel and effective thiol-ene click reaction to fabricate the cross-linked AIE-active FONs, which display excellent physicochemical and biological properties and are promising for biomedical applications.


Assuntos
Química Click/métodos , Nanopartículas/química , Polímeros/química , Ácido 3-Mercaptopropiônico/análogos & derivados , Ácido 3-Mercaptopropiônico/química , Propilenoglicóis/química , Espectrometria de Fluorescência
18.
J Liposome Res ; 29(4): 399-412, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30720378

RESUMO

The increasing incidence of venous thromboembolism (VTE) in paediatric population has stimulated the development of liquid anticoagulant formulations. Thus our goal is to formulate a liquid formulation of poorly-water soluble anticoagulant, rivaroxaban (RIVA), for paediatric use and to assess the possibility of its intravenous administration in emergencies. Self-nanoemulsifying drug delivery systems (SNEDDSs) were developed and characterized. SNEDDS constituents were estimated from the saturated solubility study followed by plotting the corresponding ternary phase diagrams to determine the best self-emulsified systems. Thermodynamic stability, emulsification, dispersibility, robustness to dilution tests, in vitro dissolution, particle size, and zeta potential were executed to optimize the formulations. The optimized formulation, that composed of Capryol 90:Tween 20:PEG 300 (5:45:50), increased RIVA solubility (285.7-fold than water), it formed nanoemulsion with a particle size of 16.15 nm, PDI of 0.25 and zeta potential of -21.8. It released 100.83 ± 2.78% of RIVA after 5 min. SNEDDS was robust to dilution with oral and parenteral fluids and showed safety to human RBCs. SNEDDS showed enhanced bioavailability after oral and intravenous administration than the oral drug suspension (by 1.25 and 1.26-fold, respectively). Moreover, it exhibited enhanced anticoagulant efficacy in the prevention and treatment of carrageenan-induced thrombosis rat model.


Assuntos
Anticoagulantes/química , Emulsões/química , Nanocápsulas/química , Rivaroxabana/química , Tromboembolia Venosa/tratamento farmacológico , Animais , Anticoagulantes/administração & dosagem , Anticoagulantes/farmacocinética , Disponibilidade Biológica , Química Farmacêutica , Liberação Controlada de Fármacos , Estabilidade de Medicamentos , Emergências , Humanos , Modelos Animais , Tamanho da Partícula , Polietilenoglicóis/química , Polímeros/química , Polissorbatos/química , Propilenoglicóis/química , Ratos , Reologia , Rivaroxabana/administração & dosagem , Rivaroxabana/farmacocinética , Solubilidade , Propriedades de Superfície , Água
19.
Int J Biol Macromol ; 128: 681-691, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30711566

RESUMO

This investigation may be of interest for researchers working on the determination of several biocatalytic properties of the laccase from Trametes versicolor. So, We will treated the effects of pH, temperature, several organic components and heavy metals by performing enzyme assays in the presence of a 2,6 dimethoxyphenol (DMP) as substrate on the laccase activity. The optimum activity and temperature are 4 and 40 °C, respectively. The maximum rate of the reaction is 124.53 U/mg and the Michaelis constant is in order of 1.23 mM. The effect of metal ions on the laccase activity with a final concentrations range varying from 1 to 5 mM show that the Cu2+ ions increase the activity for concentration inferiors to 4 mM and the other metal ions have a relative influence on the laccase activity. Four tri-block copolymers based on poly(ethylene oxide) and poly(propylene oxide) and two polyethylene glycols are used to study the synthetic polymers effects on the enzymatic activity. Also, we have demonstrated that the laccase keeps 95% of its initial activity at 60 °C in the PEGDA8000 and PEGDA6000 gel matrix. The maximum rate of the immobilized laccase is approximately around 21.03 and 47.22% smaller than the free one.


Assuntos
Biocatálise , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Lacase/química , Lacase/metabolismo , Trametes/enzimologia , Ativação Enzimática , Inibidores Enzimáticos/farmacologia , Enzimas Imobilizadas/antagonistas & inibidores , Concentração de Íons de Hidrogênio , Cinética , Lacase/antagonistas & inibidores , Metais Pesados/farmacologia , Modelos Moleculares , Polímeros/química , Propilenoglicóis/química , Conformação Proteica , Temperatura
20.
Mikrochim Acta ; 186(3): 201, 2019 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-30796531

RESUMO

This article describes the development of several nanoconjugates composed of cobalt (III) oxyhydroxide and DEASPI/ßCDP, where DEASPI stands for the dye trans-4-[p-(N,N-diethylamino)styryl]-N-methylpyridinium, and ßCDP stands for ß-cyclodextrin. The material enables sensitive fluorometric detection and 3D imaging of ascorbic acid (AA) in biological samples. A nanomicelle composed of DEASPI and ßCDP was prepared to act as a two-photon absorbance (TPA) nanofluorophore with desirable two-photon-sensitized fluorescence, high penetration depth, and excellent cell-permeability). The CoOOH nanoflakes were placed on the surface of the nanomicelle to act as both a quencher of fluorescence and as the recognition unit for AA. In the presence of AA, the CoOOH nanoflakes are reduced to Co (II), and this triggers the recovery of fluorescence. This new nanoprobe exhibits amplified two-photon fluorescence (excitation at 840 nm; emission at 565 nm), high sensitivity, and good selectivity. In-vitro imaging of endogenous AA was demonstrated in living HeLa cells. It was also employed to 3D imaging of exogenous AA in tissue by two-photon excitation microscopy to a depth of up to 320 µm. In our perception, this nanoprobe represents a valuable tool for elucidating the roles of AA in biochemical and clinical studies. Graphical abstract Schematic presentation of the preparation of a novel Poly ß-Cyclodextrin/TPdye conjugated with cobalt oxyhydroxide nanoplatform and its application for high sensitive and two-photon 3D imaging of ascorbic acid (AA) in living cells and deep tissues.


Assuntos
Ácido Ascórbico/análise , Carbocianinas/química , Cobalto/química , Nanoestruturas/química , Óxidos/química , Propilenoglicóis/química , beta-Ciclodextrinas/química , Técnicas Biossensoriais , Corantes Fluorescentes/química , Células HeLa , Humanos , Microscopia de Fluorescência por Excitação Multifotônica , Nanocompostos/química , Oxirredução , Tamanho da Partícula , Propriedades de Superfície , Distribuição Tecidual
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