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1.
Architectures and Mechanical Properties of Drugs and Complexes of Surface-Active Compounds at Air-Water and Oil-Water Interfaces.
Sarker, DK
Current drug discovery technologies. 2019;(1):11-29
Abstract
BACKGROUND Drugs can represent a multitude of compounds from proteins and peptides, such as growth hormones and insulin and on to simple organic molecules such as flurbiprofen, ibuprofen and lidocaine. Given the chemical nature of these compounds two features are always present. A portion or portions of the molecule that has little affinity for apolar surfaces and media and on the contrary a series of part or one large part that has considerable affinity for hydrophilic, polar or charged media and surfaces. A series of techniques are routinely used to probe the molecular interactions that can arise between components, such as the drug, a range of surface- active excipients and flavor compounds, for example terpenoids and the solvent or dispersion medium. RESULTS Fifty-eight papers were included in the review, a large number (16) being of theoretical nature and an equally large number (14) directly pertaining to medicine and pharmacy; alongside experimental data and phenomenological modelling. The review therefore simultaneously represents an amalgam of review article and research paper with routinely used or established (10) and well-reported methodologies (also included in the citations within the review). Experimental data included from various sources as diverse as foam micro-conductivity, interferometric measurements of surface adsorbates and laser fluorescence spectroscopy (FRAP) are used to indicate the complexity and utility of foams and surface soft matter structures for a range of purposes but specifically, here for encapsulation and incorporation of therapeutics actives (pharmaceutical molecules, vaccines and excipients used in medicaments). Techniques such as interfacial tensiometry, interfacial rheology (viscosity, elasticity and visco-elasticity) and nanoparticle particle size (hydrodynamic diameter) and charge measurements (zeta potential), in addition to atomic force and scanning electron microscopy have proven to be very useful in understanding how such elemental components combine, link or replace one another (competitive displacement). They have also proven to be both beneficial and worthwhile in the sense of quantifying the unseen actions and interplay of adsorbed molecules and the macroscopic effects, such as froth formation, creaming or sedimentation that can occur as a result of these interactions. CONCLUSION The disclosures and evaluations presented in this review confirm the importance of a theoretical understanding of a complex model of the molecular interactions, network and present a framework for the understanding of really very complex physical forms. Future therapeutic developers rely on an understanding of such complexity to garner a route to a more successful administration and formulation of a new generation of therapeutic delivery systems for use in medicine.
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2.
Influence of surfactants on anaerobic digestion of waste activated sludge: acid and methane production and pollution removal.
He, Q, Xu, P, Zhang, C, Zeng, G, Liu, Z, Wang, D, Tang, W, Dong, H, Tan, X, Duan, A
Critical reviews in biotechnology. 2019;(5):746-757
Abstract
The objective of this study is to summarize the effects of surfactants on anaerobic digestion (AD) of waste activated sludge (WAS). The increasing amount of WAS has caused serious environmental problems. Anaerobic digestion, as the main treatment for WAS containing three stages (i.e. hydrolysis, acidogenesis, and methanogenesis), has been widely investigated. Surfactant addition has been demonstrated to improve the efficiency of AD. Surfactant, as an amphipathic substance, can enhance the efficiency of hydrolysis by separating large sludge and releasing the encapsulated hydrolase, providing more substance for subsequent acidogenesis. Afterwards, the short chain fatty acids (SCFAs), as the major product, have been produced. Previous investigations revealed that surfactant could affect the transformation of SCFA. They changed the types of acidification products by promoting changes in microbial activity and in the ratio of carbon to nitrogen (C/N), especially the ratio of acetic and propionic acid, which were applied for either the removal of nutrient or the production of polyhydroxyalkanoate (PHA). In addition, the activity of microorganisms can be affected by surfactant, which mainly leads to the activity changes of methanogens. Besides, the solubilization of surfactant will promote the solubility of contaminants in sludge, such as organic contaminants and heavy metals, by increasing the bioavailability or desorbing of the sludge.
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3.
Technical approaches to evaluate the surfactant-enhanced biodegradation of biodiesel and vegetable oils.
Montagnolli, RN, Cruz, JM, Moraes, JR, Mendes, CR, Dilarri, G, Lopes, PRM, Bidoia, ED
Environmental monitoring and assessment. 2019;(9):565
Abstract
This research compared the effects of biosurfactant on the biodegradation of biodiesel and vegetable oils while validating two conceptually diverging methodologies. The two experimental setups were successfully modeled towards the effects of biosurfactants during biodegradation. We established the equivalence of both methodologies from the data output. As expected, the biosurfactants caused an increased oil uptake, thus increasing biodegradation performance. Cooking oils were favored by the microbial consortium as a carbon source when compared with biodiesel fuel, especially after use in food preparation. However, we found that biodiesel substrate standout with the highest biodegradation rates. Our results might indicate that a rapid metabolic change from the original compound initially favored biodiesels during the assimilation of organic carbon for a set specialized microbial inoculum. The data output was successfully combined with mathematical models and statistical tools to describe and predict the actual environmental behavior of biodiesel and vegetable oils. The models confirmed and predicted the biodegradation effectiveness with biosurfactants and estimated the required timeframe to achieve satisfactory contaminant removal.
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4.
Ecotoxicity and micellization behavior of anionic surfactant sodium dodecylbenzene sulfonate (SDBS) and its mixtures with nonionic surfactant fatty alcohol-polyoxyethylene ether (AEO).
Han, W, Tan, J, Peng, L, Liu, L, Zhou, X, Zhang, W, Shi, B
Aquatic toxicology (Amsterdam, Netherlands). 2019;:105313
Abstract
Surfactant mixtures have extensive industrial applications due to their ideal properties and low ecotoxicity. However, the ecotoxicity of surfactant mixtures with different proportions and their correlation with surface properties have remained poorly investigated. In this study, the ecotoxicity and surface activity of the composites of anionic surfactant sodium dodecylbenzene sulfonate (SDBS) and nonionic surfactant fatty alcohol-polyoxyethylene ether (AEO) in various mass ratios were assessed, and the correlation between ideal application properties and safe ecological perspective of the composites was explored. The ecotoxicity of individual SDBS, AEO, and SDBS/AEO mixtures was determined using the bioluminescence inhibition assay with Photobacterium phosphoreum, and the critical micelle concentrations (CMC) were measured by surface tension method and steady-state fluorescence spectroscopy. Sodium dodecylbenzene sulfonate (SDBS) showed a considerably higher toxicity than individual AEO and SDBS/AEO mixtures. Scanning electron microscope images illustrated the rupture of bacteria membrane induced by SDBS, and the addition of AEO alleviated the damage. According to the dose-response relationship on luminous bacteria, SDBS/AEO mixtures were divided into three groups (group I with a high proportion of SDBS, SDBSAEO = 4:1 and 3:2; group II, SDBSAEO = 1:1; group III with a high proportion of AEO, SDBSAEO = 2:3 and 1:4). The sequence of toxicity of the SDBS/AEO mixtures was group II > group III > group I, demonstrating that the toxicity of the composites was related to the mixture proportion instead of the amount of AEO added. The CMC order of SDBS/AEO mixtures was group II > group I > group III, and it was proportion dependent. Furthermore, ΔCM was defined as the difference of the experimental (CM) and ideal CMC (CMideal) of the mixed system, indicating the interaction between the two kinds of surfactants. The order of the ΔCM was group II > group III > group I, which was consistent with the sequence of the toxicity. Therefore, ΔCM can be a potential indicator for the hazardous assessment of surfactant mixtures involving high ionic strength.
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5.
Surfactant-Switched Positive/Negative Electrorheological Effect in Tungsten Oxide Suspensions.
Agafonov, AV, Kraev, AS, Kusova, TV, Evdokimova, OL, Ivanova, OS, Baranchikov, AE, Shekunova, TO, Kozyukhin, SA
Molecules (Basel, Switzerland). 2019;(18)
Abstract
The electrorheological (ER) effect was experimentally observed in dielectric suspensions containing tungsten oxide (WO3) modified with surfactant molecules (sodium dodecyl sulfate (SDS) and dodecylamine (DDA)) in electric fields up to several kilovolts per millimeter. The dielectric properties of WO3 suspensions in silicone oil were analyzed, depending on the frequency of the electric field, in the range from 25 to 106 Hz. Unmodified WO3 suspensions, as well as suspensions modified with sodium dodecyl sulfate, were shown to exhibit a positive electrorheological effect, whereas suspensions modified with dodecylamine demonstrated a negative electrorheological effect. The quantitative characteristics of the negative electrorheological effect in the strain-compression and shear regimes were obtained for the first time. Visualization experiments were performed to see the chain structures formed by WO3 particles modified with sodium dodecyl sulfate, as well as for dynamic electroconvection in electrorheological fluids containing WO3 modified with dodecylamine. The negative electrorheological effect was shown to be associated with the processes of phase separation in the electric field, which led to a multiplicative effect and a strong electroconvection of the suspension at field strengths above 1 kV/mm.
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6.
Improvement in the Predicted Partitioning of Alcohol and Polyethylene Oxide Groups Between Water and Octanol (logP) in Molecular Dynamics Simulations.
Warren, DB, McPhee, E, Birru, WA, Benameur, H, Chalmers, DK, Pouton, CW
Journal of pharmaceutical sciences. 2019;(1):214-222
Abstract
Molecular dynamics simulations can be applied to explore the complex liquid phase behavior of lipid-based formulations and the gastrointestinal tract lumen. In order for the results from these simulations to be of value, the manner in which molecules interact with both aqueous and oil phases present needs to be as correct as possible. An existing molecular dynamics force field, GROMOS 53a6, was demonstrated to poorly reproduce the partitioning of straight-chain alcohol and short-chain polyethylene glycol (PEG) molecules between octanol and water phase (logP), with the molecules too hydrophobic. Force field parameters for Lennard-Jones interactions between CH2 and CH3 with water oxygen were adjusted to reproduce the experimental octanol logP, with all other Lennard-Jones and force field parameters left untouched. This parameter set, called 53a6DBW, was subsequently used to recalculate straight-chain alcohol and short-chain PEG molecules, with significant improvement in the values obtained. Simulations of a nonionic surfactant in water, octaethylene glycol monocaprylate, were also performed to observe the aggregation behavior. 53a6DBW demonstrated significant improvements in water interactions with the PEG chains, well hydrating the PEG groups, and allowing the formation of micelles. Further improvements and evaluation of the improved parameter set are ongoing.
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7.
An insight of in vitro transport of PEGylated non-ionic surfactant vesicles (NSVs) across the intestinal polarized enterocyte monolayers.
Primavera, R, Palumbo, P, Celia, C, Cinque, B, Carata, E, Carafa, M, Paolino, D, Cifone, MG, Di Marzio, L, Cilurzo, F
European journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik e.V. 2018;:432-442
Abstract
PEGylated non-ionic surfactant-based vesicles (NSVs) are promising drug delivery systems for the local, oral and systemic administrations of therapeutics. The aim of this study was to test the cellular biocompatibility and transport of Nile Red-loaded NSVs (NR-NSVs) across the Caco-2-cell monolayers, which represent an in vitro model of human intestinal epithelium. The NR-NSVs assumed a spherical shape with a mean size of 140 nm, and a narrow size distribution. The NR-NSVs did not modify Caco-2 cell viability, which remained unaltered in vitro up to a concentration of 1 mM. The transport studies demonstrated that the NR-NSVs moved across the Caco-2 monolayers without affecting the transepithelial electrical resistance. These results were supported by flow cytometry analysis, which demonstrated that NR-NSVs were internalized inside the Caco-2 cells. Nanoparticle tracking and Transmission Electron Microscopy (TEM) analysis showed the presence of NR-NSVs in the basolateral side of the Caco-2 monolayers. TEM images also showed that NSVs were transported intact across the Caco-2 monolayers, thus demonstrating a predominant transcytosis mechanism of transport through endocytosis. The NSVs did not affect the integrity of the membrane barrier in vitro, and can potentially be used in clinics to increase the oral bioavailability and delivery of therapeutics.
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8.
Importance of hydrophobic interactions in the single-chained cationic surfactant-DNA complexation.
López-López, M, López-Cornejo, P, Martín, VI, Ostos, FJ, Checa-Rodríguez, C, Prados-Carvajal, R, Lebrón, JA, Huertas, P, Moyá, ML
Journal of colloid and interface science. 2018;:197-205
Abstract
The goal of this work was to understand the key factors determining the DNA compacting capacity of single-chained cationic surfactants. Fluorescence, zeta potential, circular dichroism, gel electrophoresis and AFM measurements were carried out in order to study the condensation of the nucleic acid resulting from the formation of the surfactant-DNA complexes. The apparent equilibrium binding constant of the surfactants to the nucleic acid, Kapp, estimated from the experimental results obtained in the ethidium bromide competitive binding experiments, can be considered directly related to the ability of a given surfactant as a DNA compacting agent. The plot of ln(Kapp) vs. ln(cmc), cmc being the critical micelle concentration, for all the bromide and chloride surfactants studied, was found to be a reasonably good linear correlation. This result shows that hydrophobic interactions mainly control the surfactant DNA compaction efficiency.
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9.
Surfactant and heavy metal interaction in poplar: a focus on SDS and Zn uptake.
Pierattini, EC, Francini, A, Raffaelli, A, Sebastiani, L
Tree physiology. 2018;(1):109-118
Abstract
Surfactants are widely used detergent ingredients and, thanks to their chemical properties, they are applied for remediation of sites polluted by heavy metals and organic contaminants, both in soil flushing and in phytoremediation. However, their direct effects on tree physiology especially in consociation with heavy metal pollution, as well as their possible absorption by plants, have not been appropriately investigated. In order to evaluate plant uptake/translocation of the surfactant sodium dodecyl sulfate (SDS) and the heavy metal zinc (Zn) in Populus alba L. Villafranca clone, SDS was applied alone (0.5 mM) or in combination with Zn (1 mM). Physiological effects on plant growth and photosynthetic performance were investigated. An increasing trend of Zn translocation towards basal leaves as a consequence of SDS co-treatment (1 mM Zn + 0.5 mM SDS; P = 0.03) was observed, proving the ability of SDS to improve heavy metals translocation. However, SDS exposure (both in 0.5 mM SDS and 1 mM Zn + 0.5 mM SDS treated plants) resulted in the appearance of foliar necrosis that expanded with an acropetal trend and finally led to leaf abscission. This phenotype may be caused by the emergence of an additional stress during the experimental trial, which could be related to the dissociation of sodium (Na) ions from the dodecyl sulfate molecules in the hydroponic system. In fact, while liquid chromatography-tandem mass spectrometry measurements revealed that dodecyl sulfate is mainly retained at root levels, Na is translocated to the aerial parts of the plant.
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10.
Culture Medium Development for Microbial-Derived Surfactants Production-An Overview.
Nurfarahin, AH, Mohamed, MS, Phang, LY
Molecules (Basel, Switzerland). 2018;(5)
Abstract
Surfactants are compounds that can reduce the surface tension between two different phases or the interfacial tension of the liquid between water and oil, possessing both hydrophilic and hydrophobic moieties. Biosurfactants have traits that have proven to be advantageous over synthetic surfactants, but these compounds do not compete economically with synthetic surfactants. Different alternatives increase the yield of biosurfactants; development of an economical production process and the usage of cheaper substrates during process have been employed. One of the solutions relies on the suitable formulation of a production medium by including alternative raw materials sourced from agro-wastes, hydrocarbons, or by-products of a process might help in boosting the biosurfactant production. Since the nutritional factors required will be different among microorganisms, the establishment of a suitable formulation for biosurfactant production will be challenging. The present review describes various nutrients and elements considered in the formulation of a production medium with an approach focusing on the macronutrient (carbon, nitrogen source, and C/N ratio), minerals, vitamins, metabolic regulators, and salinity levels which may aid in the study of biosurfactant production in the future.