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1.
Chemosphere ; 254: 126918, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957302

RESUMO

The increasing application of various surfactants nowadays, may lead to the contamination of the natural environment and represent potential threat to terrestrial higher plants. In this article, the effect of 13 surfactants, with dodecyl alkyl chain and various aromatic (imidazolium, pyridinium, thiazolium) and aliphatic (guanidinium, ammonium, thiosemicarbazidium) polar heads, on germination, development and growth of wheat and cucumber was investigated. The study aimed to prove how changes in lipophilicity of surfactants and their various structural modifications (existence of the aliphatic or aromatic polar group, the introduction of oxygen and sulfur) influence toxicity towards investigated plants. The calculated lipophilic parameter (AlogP) is shown to be a useful parameter for predicting potential toxicity of the compound. The strategy of using surfactants with aliphatic polar heads instead of aromatic prove to be a promising strategy in reducing harmful effect, as well as the introduction of polar groups in the structure of cation. From all investigated compounds, surfactants with imidazolium polar head displayed the most harmful effect towards wheat and cucumber. The cucumber seeds were more sensitive to the addition of surfactants comparing to wheat. All obtained experimental results were additionally investigated using computational methods, simulating the transport of surfactants through a lipid bilayer. The influence of cation tendency to fit in lipid bilayer structure was correlated with toxicity. For the first time, it is concluded that cation ability to mimic the structure of bilayer have less harmful effect on plant development.


Assuntos
Cucumis sativus/efeitos dos fármacos , Imidazóis/toxicidade , Compostos de Piridínio/toxicidade , Tensoativos/toxicidade , Triticum/efeitos dos fármacos , Cátions , Membrana Celular/química , Membrana Celular/efeitos dos fármacos , Cucumis sativus/crescimento & desenvolvimento , Germinação/efeitos dos fármacos , Imidazóis/química , Bicamadas Lipídicas/química , Simulação de Dinâmica Molecular , Compostos de Piridínio/química , Compostos de Piridínio/farmacologia , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento , Relação Estrutura-Atividade , Tensoativos/química , Triticum/crescimento & desenvolvimento
2.
Int J Pharm Compd ; 24(5): 388-395, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32886637

RESUMO

Surfactants have many applications in pharmacy. However, they must be used appropriately to prevent poor formulations and difficulties in measuring doses due to foaming, etc. It is not difficult to determine which surfactant is appropriate for different applications, to determine the appropriate hydrophilic lipophilic balance system to be used, to blend surfactants if needed, and to prepare them correctly to minimize any adverse effect on the final preparation. This article discusses several types of substances that have surfactant properties (anionic surfactants, cationic surfactants, nonionic surfactants, poloxamers) and their applications.


Assuntos
Excipientes , Tensoativos , Composição de Medicamentos/métodos , Excipientes/química , Tensoativos/química
3.
Int J Nanomedicine ; 15: 6503-6518, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32922013

RESUMO

Objective: A non-lipolysis nanoemulsion (NNE) was designed to reduce the first-pass metabolism of raloxifene (RAL) by intestinal UDP-glucuronosyltransferases (UGTs) for increasing the oral absorption of RAL, coupled with in vitro and in vivo studies. Methods: In vitro stability of NNE was evaluated by lipolysis and the UGT metabolism system. The oral bioavailability of NNE was studied in rats and pigs. Finally, the absorption mechanisms of NNE were investigated by in situ single-pass intestinal perfusion (SPIP) in rats, Madin-Darby canine kidney (MDCK) cells model, and lymphatic blocking model. Results: The pre-NNE consisted of isopropyl palmitate, linoleic acid, Cremophor RH40, and ethanol in a weight ratio of 3.33:1.67:3:2. Compared to lipolysis nanoemulsion of RAL (RAL-LNE), the RAL-NNE was more stable in in vitro gastrointestinal buffers, lipolysis, and UGT metabolism system (p < 0.05). The oral bioavailability was significantly improved by the NNE (203.30%) and the LNE (205.89%) relative to the suspension group in rats. However, 541.28% relative bioavailability was achieved in pigs after oral NNE intake compared to the suspension and had two-fold greater bioavailability than the LNE (p < 0.05). The RAL-NNE was mainly absorbed in the jejunum and had high permeability at the intestine of rats. The results of both SPIP and MDCK cell models demonstrated that the RAL-NNE was absorbed via endocytosis mediated by caveolin and clathrin. The other absorption route, the lymphatic transport (cycloheximide as blocking agent), was significantly improved by the NNE compared with the LNE (p < 0.05). Conclusion: A NNE was successfully developed to reduce the first-pass metabolism of RAL in the intestine and enhance its lymphatic transport, thereby improving the oral bioavailability. Altogether, NNE is a promising carrier for the oral delivery of drugs with significant first-pass metabolism.


Assuntos
Absorção Fisico-Química , Emulsões/química , Lipólise , Nanopartículas/química , Cloridrato de Raloxifeno/metabolismo , Administração Oral , Animais , Disponibilidade Biológica , Transporte Biológico , Sobrevivência Celular , Cães , Emulsões/administração & dosagem , Feminino , Intestinos/fisiologia , Linfa/metabolismo , Células Madin Darby de Rim Canino , Masculino , Polietilenoglicóis , Ratos Sprague-Dawley , Tensoativos/química , Suínos
4.
Int J Nanomedicine ; 15: 5217-5226, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32801687

RESUMO

Aim: Chronic use of oral nonsteroidal anti-inflammatory drugs (NSAIDs) is commonly associated with gastric irritation and gastric ulceration. Therefore, the aim of study was to develop a novel oral drug delivery system with minimum gastric effects and improved dissolution rate for aceclofenac (ACF), a model BCS class-II drug. Methods: Self-emulsifying drug delivery systems (SEDDS) were formulated to increase the solubility and ultimately the oral bioavailability of ACF. Oleic acid was used as an oil phase, Tween 80 (T80) and Kolliphor EL (KEL) were used as surfactants, whereas, polyethylene glycol 400 (PEG 400) and propylene glycol (PG) were employed as co-surfactants. Optimized formulations (F1, F2, F3 and F4) were analyzed for droplet size, poly dispersity index (PDI), cell viability studies, in vitro dissolution in both simulated gastric fluid and simulated intestinal fluid, ex vivo permeation studies and thermodynamic stability. Results: The optimized formulations showed mean droplet sizes in the range of 111.3 ± 3.2 nm and 470.9 ± 12.52 nm, PDI from 244.6 nm to 389.4 ± 6.51 and zeta-potential from -33 ± 4.86 mV to -38.5 ± 5.15 mV. Cell viability studies support the safety profile of all formulations for oral administration. The in vitro dissolution studies and ex vivo permeation analysis revealed significantly improved drug release ranging from 95.68 ± 0.02% to 98.15 ± 0.71% when compared with control. The thermodynamic stability studies confirmed that all formulations remain active and stable for a longer period. Conclusion: In conclusion, development of oral SEDDS might be a promising tool to improve the dissolution of BCS class-II drugs along with significantly reduced exposure to gastric mucosa.


Assuntos
Diclofenaco/análogos & derivados , Sistemas de Liberação de Medicamentos/métodos , Emulsões/química , Administração Oral , Animais , Anti-Inflamatórios não Esteroides/administração & dosagem , Disponibilidade Biológica , Células CACO-2 , Sobrevivência Celular/efeitos dos fármacos , Diclofenaco/administração & dosagem , Diclofenaco/farmacocinética , Liberação Controlada de Fármacos , Emulsões/administração & dosagem , Excipientes/química , Humanos , Masculino , Nanoestruturas/administração & dosagem , Nanoestruturas/química , Polietilenoglicóis/química , Polissorbatos/química , Substâncias Protetoras/administração & dosagem , Substâncias Protetoras/farmacocinética , Ratos Sprague-Dawley , Solubilidade , Tensoativos/química
5.
J Oleo Sci ; 69(9): 1021-1030, 2020 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-32788513

RESUMO

A novel jellyfish-shaped triazine hexamer quaternary ammonium chloride surfactant (TH12QC) was synthesized, which consisted of one triazine spacer group and six long flexible hydrophobic chains. The molecular structure and aggregation behavior of TH12QC was investigated by nuclear magnetic resonance (NMR), surface tension, electrical conductivity, dynamic light scattering (DLS), transmission electron microscope (TEM), etc. The results show that the jellyfish-shaped TH12QC has better surface activity and lower surface tension than traditional ionic and Gemini surfactants in aqueous solution. There are two inflection points in the curve of conductivity versus concentration of the TH12QC aqueous solution, which correspond to the critical aggregation concentration (CAC) and the critical micelle concentration (CMC) respectively. The existence of CAC indicates that there is a pre-aggregation process before TH12QC forms micelles. The results of DLS and TEM show that network pre-aggregation, spherical aggregation and dense spherical aggregation were observed in different concentration of TH12QC aqueous solution, and the electrostatic equilibrium of the system subtly depends on the concentration of the solution. In addition, intramolecular and intermolecular hydrogen bonding is also an important factor. This study provides a method for studying the aggregation behavior and morphology of oligomeric surfactants with rigid spacer groups.


Assuntos
Cloreto de Amônio/química , Cloreto de Amônio/síntese química , Compostos de Amônio Quaternário/química , Compostos de Amônio Quaternário/síntese química , Tensoativos/química , Tensoativos/síntese química , Triazinas/química , Triazinas/síntese química , Fenômenos Químicos , Difusão Dinâmica da Luz , Condutividade Elétrica , Ligação de Hidrogênio , Micelas , Estrutura Molecular , Soluções , Tensão Superficial , Água/química
6.
J Chromatogr A ; 1627: 461402, 2020 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823107

RESUMO

Surfactants are used in various applications: cosmetics, pharmaceuticals, petrochemicals, environmental, etc. Many of these compounds are polydisperse, and because of this intrinsic polydispersity, it is essential to have a universal detector with a uniform response to quantify them in a simple way. Indeed, Charged Aerosol Detector (CAD) was presented as a universal detector with a uniform response. Thus, in the present study, the CAD response, in a High-Performance Liquid Chromatography - CAD configuration (HPLCCAD), was evaluated using purified alcohol ethoxylated surfactants. A semi-preparative liquid chromatography step using a Hydrophilic interaction chromatography (HILIC) bare silica column (150 mm, 4.6 mm, 2.6 µm) was implemented to prepare eleven homologues of BrijC10, a nonionic surfactant. These homologues differed only by the number of ethylene oxide units. BrijC10 homologues were analyzed by HPLCCAD, using a HILIC bare silica column (150 mm, 2.1 mm, 2.6 µm) to determine the HPLCCAD response factors of purified homologues. From the calibration curves (from 100 to 500 mg.kg-1), their response factors were estimated: differences in response factors were observed and a maximum difference in response factors of 3.6 was obtained. Thus, it could be concluded that CAD hyphenated to HILIC separation did not present a uniform response for this homologue's distribution.


Assuntos
Aerossóis/química , Cromatografia Líquida de Alta Pressão/métodos , Calibragem , Cromatografia Líquida de Alta Pressão/normas , Etil-Éteres/química , Interações Hidrofóbicas e Hidrofílicas , Dióxido de Silício/química , Tensoativos/química
7.
Food Chem ; 332: 127461, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32659698

RESUMO

The self-microemulsifying delivery system was fabricated by whey protein isolate (WPI), daidzein (Dai) and surfactants, the interaction of WPI, Dai and D-α-Tocopherol polyethylene glycol succinate (TPGS) was hereby studied in the absence or presence of Tween 20. The increase of surfactant concentration led to the decrease of the modulus and changes of protein interfacial conformation, which allowed the formation of a strong intermolecular network. The environment and structure of WPI and daidzein could be changed by TPGS, and the addition of Tween 20 could further enhance the interaction between the components by changing TPGS structure. With the increase of surfactants and oil phase, Ksv and Ka values of WPI-Dai increased first and then decreased. Therefore, the interaction between the components was also dependent on the WPI-surfactant ration. These findings provide a potential strategy for designing microemulsion food system based on the understanding of the interactions among individual composition of microemulsions.


Assuntos
Isoflavonas/química , Tensoativos/química , Proteínas do Soro do Leite/química , Animais , Bovinos , Emulsões/química , Polietilenoglicóis/química , Polissorbatos/química
8.
Chemosphere ; 259: 127480, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32634722

RESUMO

A Na+ exchanged montmorillonite clay (Na-Mt) and its organoclay derivatives prepared with benzyldimethyltetradecylammonium (BDTA) cationic and polyoxyethylene (20)oleyl-ether (Brij-O20) non-ionic surfactants were used for first time at our knowledge as adsorbents the removal diverse pharmaceuticals (PPs) from samples collected in a rural wastewater facility (town of Josnes in France). The selected facility showed a poor efficiency for the elimination of PPs that were permanently release to the environment. Although involving different interactional mechanisms, the whole adsorbents Na-Mt, nonionic Brij-Mt and cationic BDTA-Mt organoclays, could remove the entire PPs of various chemical nature in a low concentration regime (ng L-1), where electrostatic interactions mainly controlled the adsorption. Thus, the organic PPs cations were preferentially adsorbed onto Na-Mt and Brij0.4-Mt (with its dual hydrophilic-hydrophobic nature) while anionic PPs showed a bold affinity to BDTA-Mt. The hydrophobic environment generated by the intercalation of surfactants within the interlayer space of organoclays conferred a versatility for the adsorption of numerous PPs through weak molecular forces (Van der Waals and/or pi-pi interactions). The study confirmed the proper efficiency of the studied layered materials including organoclays and emphasized about their promising interests in water remediation strategy.


Assuntos
Argila/química , Preparações Farmacêuticas/química , Eliminação de Resíduos Líquidos/métodos , Adsorção , Bentonita/química , Cátions , França , Interações Hidrofóbicas e Hidrofílicas , Tensoativos/química , Águas Residuárias/química , Água/química , Poluentes Químicos da Água/química
9.
PLoS One ; 15(7): e0236837, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32730369

RESUMO

Recent developments propose renewed use of surface-modified nanoparticles (NPs) for enhanced oil recovery (EOR) due to improved stability and reduced porous media retention. The enhanced surface properties render the nanoparticles more suitable compared to bare nanoparticles, for increasing the displacement efficiency of waterflooding. However, the EOR mechanisms using NPs are still not well established. This work investigates the effect of in-situ surface-modified silica nanoparticles (SiO2 NPs) on interfacial tension (IFT) and wettability behavior as a prevailing oil recovery mechanism. For this purpose, the nanoparticles have been synthesized via a one-step sol-gel method using surface-modification agents, including Triton X-100 (non-ionic surfactant) and polyethylene glycol (polymer), and characterized using various techniques. These results exhibit the well-defined spherical particles, particularly in the presence of Triton X-100 (TX-100), with particle diameter between 13 to 27 nm. To this end, SiO2 nanofluids were formed by dispersing nanoparticles (0.05 wt.%, 0.075 wt.%, 0.1 wt.%, and 0.2 wt.%) in 3 wt.% NaCl to study the impact of surface functionalization on the stability of the nanoparticle suspension. The optimal stability conditions were obtained at 0.1 wt.% SiO2 NPs at a basic pH of 10 and 9.5 for TX-100/ SiO2 and PEG/SiO nanofluids, respectively. Finally, the surface-treated SiO2 nanoparticles were found to change the wettability of treated (oil-wet) surface into water-wet by altering the contact angle from 130° to 78° (in case of TX-100/SiO2) measured against glass surface representing carbonate reservoir rock. IFT results also reveal that the surfactant treatment greatly reduced the oil-water IFT by 30%, compared to other applied NPs. These experimental results suggest that the use of surface-modified SiO2 nanoparticles could facilitate the displacement efficiency by reducing IFT and altering the wettability of carbonate reservoir towards water-wet, which is attributed to more homogeneity and better dispersion of surface-treated silica NPs compared to bare-silica NPs.


Assuntos
Nanopartículas/química , Óleos/isolamento & purificação , Dióxido de Silício/química , Tensoativos/química , Óleos/análise , Óleos/química , Tensão Superficial , Molhabilidade
10.
Chemosphere ; 260: 127471, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32682129

RESUMO

The aim of this work was to explore the effect of lowering pH and application of surfactants (Brij 35, Tween 20 and Saponin) in increasing bioavailability and biodegradability of benzene and o-xylene (BX) as two hydrophobic VOCs in a liquid mixture. All experiments were conducted at neutral and acidic pH to evaluate the effect of population change from bacteria to fungi on the BX biodegradation. The experiments demonstrated that acclimating wastewater inoculum at pH 4 increased the fungal to bacterial ratio. An increase of 11% for benzene and 22% for o-xylene was observed at pH 4 unamended-culture as compared to pH 7. Brij 35 was chosen as the optimum surfactant which was favorable for enhancing the bioavailability of BX at pH 4. Fitting the experimental data to pseudo first-order biodegradation kinetics model showed the BX were biodegraded faster in the presence of optimum surfactant at pH 7 than pH 4.


Assuntos
Benzeno/metabolismo , Xilenos/metabolismo , Ácidos/metabolismo , Bactérias/metabolismo , Derivados de Benzeno/metabolismo , Biodegradação Ambiental , Concentração de Íons de Hidrogênio , Cinética , Polissorbatos , Tensoativos/química , Águas Residuárias
11.
Proc Natl Acad Sci U S A ; 117(29): 16776-16781, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32636260

RESUMO

A particularly promising approach to deconstructing and fractionating lignocellulosic biomass to produce green renewable fuels and high-value chemicals pretreats the biomass with organic solvents in aqueous solution. Here, neutron scattering and molecular-dynamics simulations reveal the temperature-dependent morphological changes in poplar wood biomass during tetrahydrofuran (THF):water pretreatment and provide a mechanism by which the solvent components drive efficient biomass breakdown. Whereas lignin dissociates over a wide temperature range (>25 °C) cellulose disruption occurs only above 150 °C. Neutron scattering with contrast variation provides direct evidence for the formation of THF-rich nanoclusters (Rg ∼ 0.5 nm) on the nonpolar cellulose surfaces and on hydrophobic lignin, and equivalent water-rich nanoclusters on polar cellulose surfaces. The disassembly of the amphiphilic biomass is thus enabled through the local demixing of highly functional cosolvents, THF and water, which preferentially solvate specific biomass surfaces so as to match the local solute polarity. A multiscale description of the efficiency of THF:water pretreatment is provided: matching polarity at the atomic scale prevents lignin aggregation and disrupts cellulose, leading to improvements in deconstruction at the macroscopic scale.


Assuntos
Biotecnologia/métodos , Lignina/química , Madeira/química , Proteínas de Bactérias/metabolismo , Biomassa , Celulase/metabolismo , Furanos/química , Gluconacetobacter xylinus/enzimologia , Hidrólise , Lignina/metabolismo , Populus/química , Solventes/química , Tensoativos/química
12.
PLoS One ; 15(7): e0235473, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32634146

RESUMO

Diatoms play a key role in the marine carbon cycle with their high primary productivity and release of exudates such as extracellular polymeric substances (EPS) and transparent exopolymeric particles (TEP). These exudates contribute to aggregates (marine snow) that rapidly transport organic material to the seafloor, potentially capturing contaminants like petroleum components. Ocean acidification (OA) impacts marine organisms, especially those that utilize inorganic carbon for photosynthesis and EPS production. Here we investigated the response of the diatom Thalassiosira pseudonana grown to present day and future ocean conditions in the presence of a water accommodated fraction (WAF and OAWAF) of oil and a diluted chemically enhanced WAF (DCEWAF and OADCEWAF). T. pseudonana responded to WAF/DCEWAF but not OA and no multiplicative effect of the two factors (i.e., OA and oil/dispersant) was observed. T. pseudonana released more colloidal EPS (< 0.7 µm to > 3 kDa) in the presence of WAF/DCEWAF/OAWAF/OADCEWAF than in the corresponding Controls. Colloidal EPS and particulate EPS in the oil/dispersant treatments have higher protein-to-carbohydrate ratios than those in the control treatments, and thus are likely stickier and have a greater potential to form aggregates of marine oil snow. More TEP was produced in response to WAF than in Controls; OA did not influence its production. Polyaromatic hydrocarbon (PAH) concentrations and distributions were significantly impacted by the presence of dispersants but not OA. PAHs especially Phenanthrenes, Anthracenes, Chrysenes, Fluorenes, Fluoranthenes, Pyrenes, Dibenzothiophenes and 1-Methylphenanthrene show major variations in the aggregate and surrounding seawater fraction of oil and oil plus dispersant treatments. Studies like this add to the current knowledge of the combined effects of aggregation, marine snow formation, and the potential impacts of oil spills under ocean acidification scenarios.


Assuntos
Diatomáceas/efeitos dos fármacos , Poluição por Petróleo/efeitos adversos , Petróleo/toxicidade , Tensoativos/efeitos adversos , Organismos Aquáticos/efeitos dos fármacos , Humanos , Hidrocarbonetos Policíclicos Aromáticos/efeitos adversos , Hidrocarbonetos Policíclicos Aromáticos/química , Água do Mar/química , Tensoativos/química , Poluentes Químicos da Água/efeitos adversos , Poluentes Químicos da Água/química
13.
Chemosphere ; 257: 127223, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32534295

RESUMO

The degradation performance of trichloroethylene (TCE) by sodium percarbonate (SPC) activated with citric acid (CA) chelated Fe(II) in the presence of nonionic surfactant Tween-80 was investigated. The addition of CA successfully prevented the precipitation of iron and facilitated TCE degradation. However, Tween-80 had an inhibitory effect on TCE degradation mainly due to the competition of ∗OH between Tween-80 and TCE. The effect of SPC and Fe(II) dosage on TCE degradation was also explored and the results displayed that 87.2% of TCE could be degraded in 15 min at the SPC/Fe(II)/CA/TCE molar ratio of 3/4/2/1. Free radical probe tests confirmed that both O2-∗ and ∗OH were generated in the SPC/Fe(II)/CA system. Free radical scavenging tests implied that the degradation of TCE in the SPC/Fe(II)/CA system was mainly attributed to ∗OH, while O2-∗ was only partially involved in the degradation of TCE. In addition, TCE removal was suppressed with the raising of the initial solution pH from 3.0 to 9.0. The actual groundwater (containing Tween-80) tests confirmed that 93.2% of TCE degradation could be achieved at the SPC/Fe(II)/CA/TCE molar ratio of 30/40/10/1 and strongly demonstrated that the SPC/Fe(II)/CA process has potential for the in situ treatment of TCE contaminated groundwater in the presence of surfactant Tween-80. In conclusion, TCE degradation by Fe(II) activated SPC system in the presence of Tween-80 can be significantly enhanced with the addition of CA, and this finding offers an innovative direction for removing chlorinated organic contaminants from groundwater in contaminated site after surfactant solubilization treatment.


Assuntos
Carbonatos/química , Tensoativos/química , Tricloroetileno/química , Poluentes Químicos da Água/química , Quelantes , Ácido Cítrico , Compostos Ferrosos/química , Água Subterrânea , Ferro , Oxirredução , Polissorbatos , Surfactantes Pulmonares , Poluentes Químicos da Água/análise
14.
J Chromatogr A ; 1623: 461204, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505292

RESUMO

Deep eutectic solvents (DESs) were used as an extractant for the determination of pyrethroids in environmental water and tea beverage samples. Three different acids were chosen as hydrogen bond donors for preparation of DESs, and decanoic acid was optimal because of its high recovery. Factors affecting relative recovery were optimized individually, including salt addition, surfactant addition, extraction temperature, DES amount, and sample volume etc. Under the optimized experimental conditions, the relative recovery of pyrethroids was from 89.3% to 97.7%, with relative standard deviation (RSD) values ranging from 1.75% to 2.73%. The linear correlation coefficient ranged from 0.9981 to 0.9992, and the linear range was between 1.9 and 500 µg/L. Based on a signal-to-noise ratio (S/N) of 3:1, the limit of detection (LOD) values were 0.56 to 1.24 µg/L. The enrichment factor ranged from 92 to 105. In conclusion, good extraction efficiency was achieved in tea beverage samples under the optimized conditions.


Assuntos
Bebidas , Emulsões/química , Interações Hidrofóbicas e Hidrofílicas , Microextração em Fase Líquida/métodos , Piretrinas/análise , Solventes/química , Chá/química , Cromatografia Líquida de Alta Pressão/métodos , Limite de Detecção , Cloreto de Sódio/química , Tensoativos/química , Temperatura , Água/química
15.
J Chromatogr A ; 1623: 461212, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505296

RESUMO

Non-ionic surfactants such as polysorbates, known as Tween™ 20 and Tween™ 80, are routinely used within the healthcare and pharmaceutical industry to enhance solubility. This work focuses on analysing the two aforementioned polysorbates, each considered at three purity levels with four model compounds, across the critical micellar concentration (CMC) range for each surfactant. Such data is of interest to investigate the influence of micelle formation upon compound-polysorbate interaction. Two analytical techniques were utilised, namely spectroscopic solubility determination and micellar liquid chromatography (MLC). In all cases it was apparent that the maximum solubility for all four compounds increased substantially at concentrations greater than the CMC and that, in most cases, a different retention profile was observed using MLC once the CMC had been exceeded. This paper is the first to have used such techniques to investigate the behaviour of these polysorbates over a series of concentrations and three levels of polysorbate purity. The findings indicate that the solubilisation potential of polysorbates differs once the CMC has been surpassed and is dependent upon the level of purity selected, i.e. compound-surfactant interactions are partially a consequence of the presence of micelles rather than monomer as well as polysorbate purity. Thus, formulators should include such polysorbates at optimised concentrations and purity if they wish to maximise their solubilisation potential.


Assuntos
Micelas , Polissorbatos/química , Acetaminofen/análise , Benzamidas/análise , Cromatografia Líquida , Hidrocortisona/análise , Solubilidade , Tensoativos/química
16.
Ecotoxicol Environ Saf ; 201: 110798, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32526591

RESUMO

Despite constant progress in the understanding of the mechanisms related to the effects of biosurfactants in the bioremediation processes of oily residues, the possibility of antagonist effects on microbial growth and the production in situ of these compounds must be elucidated. The aims of this work were a) to evaluate the effects of the addition of a homemade biosurfactant of Bacillus methylotrophicus on the microbial count in soil in order to determine the possibility of inhibitory effects, and b) to accomplish biostimulation using media prepared with whey and bioaugmentation with B. methylotrophicus, analyzing the effects on the bioremediation of diesel oil and evidencing the in situ production of biosurfactants through effects on surface tension. The homemade bacterial biosurfactant did not present inhibitory effects acting as a biostimulant until 4000 mg biosurfactant/kg of soil. The biostimulation and bioaugmentation presented similar better results (p > 0.05) with the degradation of oil (~60%) than natural attenuation due to the low quantities of biostimulants added. For bioaugmentated and biostimulated soils, a decrease of surface tension between 30 and 60 days was observed, indicating the production of tensoactives in the soil, which was not observed in natural attenuation or a control treatment.


Assuntos
Bacillus/efeitos dos fármacos , Argila/química , Petróleo/análise , Poluentes do Solo/análise , Solo/química , Tensoativos/farmacologia , Bacillus/crescimento & desenvolvimento , Bacillus/metabolismo , Biodegradação Ambiental , Petróleo/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Tensoativos/química
17.
Nat Commun ; 11(1): 2793, 2020 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-32493905

RESUMO

Biology utilizes multiple strategies, including sequestration in lipid vesicles, to raise the rate and specificity of chemical reactions through increases in effective molarity of reactants. We show that micelle-assisted reaction can facilitate native chemical ligations (NCLs) between a peptide-thioester - in which the thioester leaving group contains a lipid-like alkyl chain - and a Cys-peptide modified by a lipid-like moiety. Hydrophobic lipid modification of each peptide segment promotes the formation of mixed micelles, bringing the reacting peptides into close proximity and increasing the reaction rate. The approach enables the rapid synthesis of polypeptides using low concentrations of reactants without the need for thiol catalysts. After NCL, the lipid moiety is removed to yield an unmodified ligation product. This micelle-based methodology facilitates the generation of natural peptides, like Magainin 2, and the derivatization of the protein Ubiquitin. Formation of mixed micelles from lipid-modified reactants shows promise for accelerating chemical reactions in a traceless manner.


Assuntos
Lipídeos/química , Micelas , Peptídeos/química , Tensoativos/química , Sequência de Aminoácidos , Cinética , Luz , Magaininas/síntese química , Magaininas/química , Peptídeos/síntese química , Ubiquitina/metabolismo
18.
J Oleo Sci ; 69(6): 549-555, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32522916

RESUMO

Foam separation can selectively remove a target substance from a solution via adsorption of the substance with the surfactant at the surface of the bubble. A cationic dye, methylene blue, and an anionic dye, Fast Green FCF, were prepared as substances to be removed via foam separation. Anionic (sodium dodecyl sulfate, SDS), cationic (dodecyltrimethylammonium chloride, DTAC), and amphoteric (3-(dodecyldimethylammonio)propane-1-sulfonate, SB-12) surfactants were used in the foam separation process. The effectiveness of the surfactants for removing the cationic methylene blue increased as follows: DTAC < SB-12 < SDS. On the other hand, the effectiveness of the surfactants for removing the anionic Fast Green FCF was in the opposite order. The dyes were effectively adsorbed by the foams via electrostatic interactions between the oppositely charged surfactant and the dye molecules. Since amphoteric surfactants have both anionic and cationic charges in a molecule, they could effectively remove both dyes in the foam separation process. Therefore, it was found that the amphoteric surfactant was highly versatile. Analysis of the kinetics of the removal rate showed that the aqueous solutions of monomers could remove the dyes more effectively than micellar solutions in foam separation.


Assuntos
Corantes/química , Corantes Verde de Lissamina/química , Azul de Metileno/química , Compostos de Amônio Quaternário/química , Dodecilsulfato de Sódio/química , Tensoativos/química , Adsorção , Sistemas de Transporte de Aminoácidos Básicos , Ânions , Eletricidade Estática
19.
J Oleo Sci ; 69(6): 563-567, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32522917

RESUMO

Foam separation promotes the removal of dissolved materials from solutions by adsorbing the molecules onto a surfactant. The zwitterion of rhodamine B was removed by using both anionic (sodium dodecyl sulfate: SDS) and cationic (dodecyltrimethylammonium chloride: DTAC) surfactants through foam separation. However, rhodamine B could not be removed from a strongly acidic DTAC solution (pH 2), because the molecular form changes from the zwitterion to cation. Moreover, the cationic dye of rhodamine 6G could not be removed from the DTAC solution. Therefore, these results demonstrate that the electrostatic interaction between a surfactant and target ion is an important factor in foam separation.


Assuntos
Compostos de Amônio Quaternário/química , Rodaminas/isolamento & purificação , Dodecilsulfato de Sódio/química , Tensoativos/química , Adsorção , Cátions , Concentração de Íons de Hidrogênio , Íons , Soluções , Eletricidade Estática
20.
Food Chem ; 327: 127039, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32454273

RESUMO

In this study, we investigated the tailoring of food emulsions using interactions between rice bran cellulose nanocrystals (CNCs) and lauric arginate (LAE), which is food-grade cationic surfactant. Complexes of anionic CNCs and cationic LAE (CNCs/LAE) were formed through electrostatic attraction which were characterized using isothermal titration calorimetry (ITC), turbidity, and zeta-potential measurements. The saturation complexes could be formed at ratios of 1:2 (w/w) CNCs-to-LAE. Furthermore, the physical and oxidative stability of oil-in-water emulsions containing lipid droplets coated by CNCs/LAE complexes was determined. Electrostatic complexes formed from 0.02% CNCs and 0.1% LAE produced stable Pickering emulsions that were resistant to droplet coalescence. It was also exhibited that 0.02% CNCs and 0.1% LAE complexes stabilized-emulsions was able to extend the lag phase to 20 days for lipid hydroperoxide and to 14 days for hexanal production. This study shows that food-grade Pickering emulsions with good stability can be produced by CNCs with LAE complexes.


Assuntos
Arginina/análogos & derivados , Celulose/química , Alimentos , Nanopartículas/química , Óleos/química , Tensoativos/química , Água/química , Arginina/química , Emulsões , Eletricidade Estática
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