Surfactant Type Research Articles

Deep insight into the effect of smithsonite particle size on surface heterogeneity and adsorption behavior: A case of fatty acid system

The studies for microfine mineral flotation have focused on the two main directions of increasing the apparent mineral particle size and reducing the bubble size, while little research has been reported on the special surface properties and adsorption mechanisms of mineral particles of different sizes. In this study, sodium oleate was chosen as a typical surfactant. The mechanism of the effect of smithsonite particle size on the heterogeneity and adsorption behavior of the mineral surface was explored in depth. Through microflotation experiments, BET area tests, Washburn contact angle tests, particle agglomeration tests, adsorption tests and inorganic carbon analysis, it was pointed out that the smaller the size of the particles, the greater the surface wettability, and the smaller the density and thickness of adsorbed oleate on the surface. The difficulty of encapsulating the mineral surface with a hydrophobic layer of oleate hydrocarbon chains, as well as suboptimal particle aggregation sizes, are key reasons for the poor flotation behavior of fine smithsonite. Furthermore, the inhomogeneity of active sites and charge distribution of surface components of smithsonite with different sizes was revealed from a microscopic point of view by DRIFT spectroscopic analysis, XPS analysis and zeta potential measurements. As the particle size of smithsonite decreases, the positive charge density on the surface is higher and the hydration tendency is more intense, hindering the adsorption of oleate. This work is expected to guide the full particle size recovery of minerals in the flotation from a novel microscopic point of view.

ТЕХНОЛОГИЯ ПОЛУЧЕНИЯ НАНОКАПСУЛ ДЛЯ ДОСТАВКИ ЛЕКАРСТВЕННЫХ СРЕДСТВ

Encapsulation of active ingredients in solid capsules made of biodegradable materials has attracted considerable attention over the past decades. In this brief review, we focus on the preparation of micro- and nanosized capsules and emulsions based on artificial peptides as a fully degradable material. It discusses various approaches to the preparation of polymer-based capsules as well as their critical properties such as size and stability. Dispersed polymer nanocapsules can serve as nanosized drug carriers to achieve controlled release as well as effective drug administration. The stability of the dispersion is determined by the type of surfactant and the nature of the outer shell of the capsule. Their release and degradation properties largely depend on the composition and structure of the capsule walls. Another important criterion is the capsule size, where the optimum is usually observed in the radius range of 100 to 500 nm. Nanocapsules can be prepared in fundamentally different ways: nanoprecipitation, emulsion diffusion, double emulsification, emulsion coacervation, polymer coating and layer-by-layer, and depend on the methodological and mechanistic aspects, encapsulation of the active substance and the raw materials used. Nanocapsules made using various biodegradable polymers are attracting increasing attention and are considered as one of the most promising drug delivery systems. Nanoencapsulated systems have a relatively higher intracellular absorption compared to microparticles, which can be modified depending on the surface charges of the nanocapsules and the hydrophilic or hydrophobic nature of the polymer used to form the shell.

Prognostic value of alveolar surfactant type-B in acute heart failure: a long-term comparative analysis vs NT-proBNP

Abstract Background In heart failure (HF) biomarkers are an integral component of prognostic assessment. Natriuretic peptides are the gold standard, but they do not directly reflect lung vascular injury. Surfactant type B (Surf-B) is released by type 2 alveolar cells under pressure induced trauma, with few reports just addressing its plasmatic levels in stable chronic HF (CHF). Information on acute HF (AHF) is lacking. Purpose To clarify the prognostic value of Surf-B changes vs NT-proBNP levels after decongestion therapy and to compare their prognostic ability at 1-year follow-up. Methods Patients with acute pulmonary edema (APE) underwent a combined evaluation of Surf-B and NT-proBNP serum levels with quantification of B-lines at hospital admission (time 0), discharge (time 1) and at 1 year (time 2). Results 54 patients (mean age 72.1 ± 11 years; mean LVEF 36% ± 13%; 65% men) were enrolled. At time 1, the average Surf-B, NT-proBNP and B-lines were significantly reduced compared to time 0 (p<0.0001). No correlation between Surf-B and NT-proBNP was observed either at time 0 (r=-0.21; p=0.12) or at time 1 (r=0.05; p=0.71). Despite the significant decrease in Surf-B levels from time 0 to time 1, 18.5% of patients behaved as non-responders exhibiting no changes in Surf-B; conversely, only 5.5% did not show significant reduction in NT-proBNP, despite significant decongestion. 38 patients were followed up to time 2: of these, 13 (34%) reached the composite endpoint of death or hospitalization for HF. Surf-B measured at time 1 was a strong predictor of adverse outcome. Patients with Surf-B above median at discharge displayed a worse survival-free from HF hospitalization compared to the remainders (Log rank p=0.012) (Figure). Also, patients with Surf-B above median at discharge had a more than 4-fold increased risk of the composite endpoint (HR 4.5, 95%CI 1.4-20.2, p=0.023). Conversely, NT-proBNP at discharge was not significantly associated with HF-free survival (Log rank p=0.26) (Figure) and was not a significant predictor of the composite outcome (HR 1.9, 95%CI 0.6-9.3, p=0.25). At ROC analysis, discharge Surf-B levels showed a higher area under the curve (AUC=0.763, p=0.011) than NT-proBNP values (AUC=0.69, p=0.063). Conclusions These data suggest that Surf-B, an organ specific biomarker of lung injury, is highly sensitive to the effectiveness of decongestion therapy, outperforming NT-proBNP. Given the high rate of patients who do not improve their Surf-B levels over time, the reparative processes of alveolar break damage may dissociate from mere decongestion and cardiac healing in AHF.Figure:1yr Kaplan-Meier survival curves

Quartz crystal microbalance analysis of effects of surfactants on dissolution kinetics of poly(4-hydroxystyrene) partially protected with t-butoxycarbonyl group

Abstract Surfactants comprise water-repellent and water-attracting moieties and have been used to improve the lithographic performance of resist materials. However, the effects of surfactants on the dissolution kinetics of these materials are still unclear. In this study, the effects of surfactants on the dissolution kinetics of partially-protected poly(4-hydroxystyrene) (PHS) in 0.26 N tetramethylammonium hydroxide aqueous solution was investigated using a quartz crystal microbalance method. Anionic (sodium n-octanonate, sodium 1-hexanesulfonate, n-dodecylbenzenesulfonic acid, and sodium n-dodecyl sulfate), cationic (methylamine hydrochloride, dodecyltrimethylammonium chloride, and 30% ammonium lauryl sulfate solution), nonionic (sorbitan monooleate, polyoxyethylene(23)lauryl ether, and polyoxyethylene(10)hydrogenated castor oil), and amphoteric (35% lauryl dimethylaminoacetic acid solution) surfactants were examined. The surfactant significantly affected the dissolution kinetics of the PHS films. The surfactant effects were significantly reduced by protecting the hydroxyl groups of PHS. The effect of the surfactant on the dissolution kinetics depended on the surfactant rather than on the surfactant type.

Effect of CTAB and NaBH4 Solutions on Ti and Cu Nanoparticles Prepared by Pulsed Laser Ablation

The effect of different media, including cetyltrimethylammonium bromide (CTAB) and sodium borohydride (NaBH4), on the size, shape, optical absorption, and stability of titanium (Ti) and copper (Cu) nanoparticles (NPs) synthesized by laser ablation in liquid, was investigated. Ti and Cu NPs were fabricated by irradiating Ti and Cu targets using a Nd:YAG pulsed laser with a wavelength of 1064 nm, an energy of 500 mJ, repetition rate of 1 Hz, and a number of pulses of 1000. Results showed the direct effect of the type of surfactant on the size and size distribution of Ti and Cu NPs under the same laser ablation parameters. Morphological properties were described by field emission scanning electron microscope (FESEM) images, which revealed the formation of semispherical particles. The EDS results confirmed the spike-induced synthesis of Ti and Cu in CTAB and NaBH4 solutions. The transmission electron microscopy (TEM) images showed the nanostructures of Ti and Cu with spherical particles. The UV-vis absorption spectra showed that the absorption peak of Ti was almost constant at 289 nm, while the peak of Cu disappeared for both solutions. Zeta potential analysis showed that NPs prepared in CTAB solution were more stable than those in NaBH4 solution.

Evaluating surfactant effectiveness in preventing antibody adsorption directly on medical surfaces using a novel device

Biopharmaceuticals, specifically antibody-based therapeutics, have revolutionized disease treatment. Throughout their lifecycle, these therapeutic proteins are exposed to several stress conditions, for example at interfaces, posing a risk to the drug product stability, safety and quality. Therapeutic protein adsorption at interfaces may lead to loss of active product and protein aggregation, with potential immunogenicity risks. Non-ionic surfactants are commonly added in formulations to mitigate protein-surface interactions. However, their effectiveness varies with the monoclonal antibody (mAb), and model surface material. Extrapolating findings from model surfaces to real medical surfaces is challenging due to diverse properties.This study pioneers the evaluation of surfactant effectiveness in preventing mAb adsorption directly on medical surfaces at the medical bag/formulation interface, utilizing the ELIBAG device. The adsorption of different protein modalities, mAbs and antibody-drug conjugate (ADC), using three surfactants (PS80, PS20, and P188), was examined across various medical surfaces, IV bags and manufacturing bags, and model surfaces. Our findings reveal that surfactants prevent mAb adsorption depending on the mAb modality, surfactant type and concentration, and surface material. This research underscores the importance of considering real medical surfaces in direct contact with formulations, offering insights for enhancing drug product development and ensuring material-protein compatibility in real world use.

CO2 foam structure and displacement dynamics in a Hele–Shaw cell

The substitution of CO2 gas with CO2 foam for improved mobility control has recently attracted research attentions in enhanced oil recovery (EOR) as well as aquifer and soil remediation. However, the interplay between CO2 foam properties and oil displacement remains less investigated. In this work, using clear visualizations, we systematically investigate the dynamic advection-dominated foam morphology, its corresponding viscosity, and the efficiency and dynamics of oil displacement process by CO2 foam in a Hele–Shaw cell under the effects of gas ratio (Rg), fluid injection rates (Qt), and surfactant type. Clear visualization enables particle image velocimetry to calculate actual, rather than nominal, foam velocity that significantly affects the estimated foam viscosity. Our results demonstrate that at elevated gas ratios under constant total injection rate, larger and more uniform bubbles with less number density and greater interfacial area are obtained. Increasing the injection rates leads to finer foam texture at a constant gas ratio. Different foam structures have an impact on the foam viscosity, with a general increasing trend of viscosity for larger bubbles as Rg increases from 0.5 to 0.85. The higher the foam viscosity, the more stable displacement interfaces with less viscous fingers are observed, leading to improved sweeping rates. The green surfactants (saponin + Cellulose NanoFibers) provide foams with higher viscosity and, thus, more stable displacement interfaces. These findings highlight the important effect of Rg–dependent foam structure on its viscosity, which in turn is crucial for controlling the mobility of CO2 foam to maximize oil recovery rate during EOR processes.

Study on the Effect of Emulsifiers on the Properties of Oleogels Based on Olive Oil Containing Lidocaine

Oleogels are semi-solid materials that consist primarily of liquid oil immobilized in a network of organized structural molecules, which provide stability and maintain the oil in the desired shape. Due to their structure, oleogels can stabilize large amounts of liquid, making them excellent carriers for active substances, both lipophilic and hydrophilic. This study presents the synthesis methodology and investigations of olive oil-based oleogels, which are among the healthiest and most valuable vegetable fats, rich in unsaturated fatty acids and antioxidants such as vitamin E. Two types of surfactants were used: TWEEN 80, which lowers surface tension and stabilizes emulsions, and SPAN 80, which acts in oil-dominated phases. The oleogels were enriched with lidocaine, an active substance commonly used as a pain reliever and local anesthetic. This research characterized the obtained oleogels regarding their medical applications, paying particular attention to the influence of surfactant type and amount as well as the active substance on their physicochemical properties. Structural analyses were also conducted using Fourier transform infrared (FTIR) spectroscopy, alongside rheological and sorption studies, and the wettability of the materials was evaluated. The stability of the obtained oleogels was verified using the MultiScan MS20 system, allowing for an assessment of their potential suitability for long-term pharmaceutical applications. The results indicated that SPAN-stabilized oleogels exhibited better stability and favorable mechanical properties, making them promising candidates for medical applications, particularly in pain relief formulations.

Adsorption, Aggregation, and Application Properties of Green Pluronic Aliphatic Alcohol Ether Carboxylic Acids and Nonionic/Amphoteric Surfactants in Water.

In the realm of colloid and interface science, new types of green surfactants, including anionic Pluronic alcohol ether carboxylate (AEC), branched alkyl glucoside (IG), and zwitterionic coconut oil amide propyl betaine (CAB), have been identified and merit further exploration. AEC, characterized by its inclusion of 5 EO and 3.5 PO units, was synthesized, and its behavior in aqueous solutions with IG and CAB was meticulously examined. Their performance in applications such as foam generation, wetting, and the dispersion and stabilization of graphene was also evaluated. At αAE5P3C = 0.5, AE5P3C/CAB exhibited superior surface and interfacial properties compared to AE5P3C/IG. In these hybrid systems, the self-assembly of micelles is predominantly influenced by hydrogen bonding, electrostatic interactions, and hydrophobic forces. Kinetic analysis further confirmed that the driving force for micelle formation in these hybrid systems is enthalpy, with the adsorption process involving a mixed diffusion-kinetic adsorption mechanism. AE5P3C/CAB demonstrated enhanced foaming ability, foam stability, and wetting properties compared to AE5P3C/IG. Intriguingly, the optimal dispersion and stabilization of graphene were achieved with AE5P3C/IG at αAE5P3C = 0.2, providing a foundational basis for its potential application in graphene-based systems. A thorough examination of the synergistic mechanisms and application potential of these three distinct surfactants in aqueous solutions was presented, taking into account various charged ions and the specific hydrophilic and hydrophobic groups of EO and PO. This study not only provides fundamental insights into their intrinsic properties but also offers a fresh perspective for the ongoing exploration of green surfactants.

Natural surfactant used as an additive in the enzymatic-homogenate synergistic extraction of piceatannol, resveratrol, and myricetin from the myrtle (Rhodomyrtus tomentosa) fruit

In this study, three different target analytes from the fruit of myrtle (Rhodomyrtus tomentosa) were extracted via an enzymatic-homogenate synergistic extraction (EHSE) process, and 10 different aqueous solutions of natural surfactants were selected as extraction solvents, thus enabling the simultaneous extraction of piceatannol, resveratrol, and myricetin from the fruit of myrtle (Rhodomyrtus tomentosa). Important factors affecting the yield of piceatannol, resveratrol, and myricetin, including enzyme type, enzyme concentration, pH, surfactant type and dosage, homogenization time, liquid‒solid ratio, incubation and extraction time, incubation time and extraction temperature, were optimized via single-factor experiments. Three important parameters were optimized via the Box‒Behnken design: the liquid‒solid ratio, the incubation–extraction time, and the reaction temperature. The final optimum extraction process conditions were as follows: β-glucosidase concentration, 3.0%, homogenate; time, 3 min; pH, 5; tea saponin concentration, 0.8%; liquid‒solid ratio, 45 mL/g; incubation–extraction time, 2.5 h; and temperature, 67.5 °C. With the optimized experimental parameters, the piceatannol, resveratrol, and myricetin yields were 742.12 ± 37.11 μg/g, 18.58 ± 0.94 μg/g, and 24.83 ± 1.25 μg/g, respectively. Methodological validation and comparison experiments with traditional solvents demonstrated that EHSE is a successful, green, and safe method for extracting active plant components. This approach employs an ecologically benign water-based solution of tea saponin as the extraction solvent, and it combines enzymatic and homogenate procedures to increase extraction efficiency. This study provides a reasonable basis for the application and research of synergistic extraction technology and suggests that more diverse solvent choices should be considered.

Optimization of the experimental design parameters for synthesis of Fluconazole loaded transethosomes as nano-based antifungal vesicles

Introduction: Antifungal drugs formulated in conventional pharmaceutical forms are not fully effective due to various factors. New approaches have focused on transdermal delivery drugs, including transethosomes, where the mixture of ethanol and surfactant allows a deeper drug skin’s penetration. Formulation parameters and process variables can make their optimization a considerable challenge. This study aimed to formulate Fluconazole-loaded transethosomes using a full-factorial design with the goal of optimizing formulation and process variables. Method: Fluconazole transethosomes were developed using the cold Method. A 21,31 full-factorial design was created by Design Expert® Software, where the impact of surfactant’s type and soy lecithin to surfactant ratio on resulting formulation were investigated. The formulations were tested for vesicle size, polydispersity index, zeta potential and entrapment efficiency. Results: Formulations containing Tween®80 presented the smaller particle sizes and showed a considerable entrapment efficiency for Fluconazole, they were more homogenous and highly stable compared to those prepared with Span®80. The optimized soy lecithin to surfactant ratio of 90:10 with Tween®80 was deemed apt for the synthesis of transethosomes giving the optimal formulation with a small particle size (300.2±5.57 nm), a low PDI (0.203±0.004), a good zeta potential (−31.75±0.68 mV) and a high entrapment efficiency (88.11±0.74 %). Conclusion: This study enabled the in-depth identification and optimization of the key factors involved in the experimental process, such as the type of surfactant used and the soybean lecithin-to-surfactant ratio. To ensure safety and effectiveness in use, this work provides the perspective of continuing the study by evaluating the antifungal activity, long-term stability and safety of Fluconazole-loaded transethosomes.

Thermal insulation and fire protection plaster for FRP systems incorporating aerogel nanoparticles and phyllosilicates

Fiber Reinforced Polymers (FRP) Systems are the most advanced systems in structural repair and strengthening field for their minimal time of application, limited space needed, and high durability. However, FRP systems still have a major drawback that limits their utilization in many projects, namely low fire-resistance. A novel material that was introduced lately with a substantial thermal performance is Aerogel, which has been widely utilized in other fields. This study attempted to develop fire-protective plaster incorporating nano silica-aerogel particles and phyllosilicates. During the experimental process, different surfactants were assessed as wetting agents, and their impact on both cement and mineral matrices. Finally, the selected plaster was evaluated under fire conditions. The results reveal that aerogel incorporation in mineral (gypsum) matrix was successfully achieved using various types of surfactants. The mechanical and thermal performance of the developed plasters were promising, with a fire-rating performance reaching 82 minutes for FRP system.

Experimental and molecular dynamics simulation of the effect of surfactant concentration on the wettability of bituminous coal

Currently, studies on the mechanism of coal dust wetting have largely ignored the key factor of surfactant concentration, so it is of significant scientific value to systematically investigate the effect of concentration change on the efficacy of surfactant wetting of coal dust. In this paper, with the help of macroscopic wettability experiments and molecular dynamics simulations, the wetting characteristics of SDBS surfactant on coal at different concentrations were analyzed in depth. An increase in the concentration of the SDBS surfactant solution causes the wettability of the coal to show a crest change that increases and then decreases. Coal wettability is optimized when the solution concentration reaches a specific threshold of 7 wt%. The simulation results show that SDBS surfactant mostly forms hydrogen bonds with water molecules in the form of strong hydrogen bonds, and the hydrogen bonding ability with water molecules is stronger than that of coal. There is a positive correlation between the onset distribution of water molecules within coal and the overlap region at the coal/water interface. The dynamic properties of water molecules show the order E<F<D<C<B<A. The number of highly active sites does not continuously increase with the amount of SDBS molecules adsorbed, but begins to decrease after a critical point is reached. The results of the study contribute to a theoretical framework to guide and use different types of surfactants to improve coal dust wettability at various concentration levels.

Construction of Carbon Dioxide Responsive Graphene Point Imbibition and Drainage Fluid and Simulation of Imbibition Experiments

The global oil and gas exploration targets are gradually moving towards a new field of oil and gas accumulation with nanopore throats, ranging from millimeter scale to micro-nano pore throats. The development method of tight oil reservoirs is different from that of conventional oil reservoirs, and the development efficiency is constrained. Therefore, it is necessary to construct a nanoscale fluid with strong diffusion and dispersion and improve its permeability, suction, and displacement capabilities. Under the background of CCUS, carbon dioxide flooding is a better way to develop tight reservoirs. However, in order to solve the problem of gas channeling, this paper developed a carbon dioxide-responsive graphene point type surfactant, which has a good gas–liquid synergistic effect. At the same time, graphene nanomaterials are carbon-based and create no environmental damage in oil reservoirs. In this study, graphene quantum dots (GQDs) were prepared using the hydrothermal method, and functional graphene quantum dots (F-GQDs) responsive to carbon dioxide stimulation were synthesized by covalent grafting of amidine functional groups. By characterizing its structure and physical and chemical properties, and by conducting imbibition simulation experiments, its imbibition and drainage ability in nanopore throats is elucidated. Infrared spectrum measurement shows that after functional modification, the quantum dots exhibited new characteristic peaks at 1600 cm−1 to 1300 cm−1, considering the N-H plane-stretching characteristic peak. The fluorescence spectra showed that the fluorescence intensity of F-GQDs was increased after functional modification, which indicated that F-GQDs were successfully synthesized. Through measurements of interfacial activity and adhesion work calculations, the oil–water interfacial tension can achieve ultra-low values within the range of 10−2 to 10−3 mN/m. Oil sand cleaning experiments and indoor simulations of spontaneous imbibition in tight cores demonstrate that F-GQDs exhibit effective oil-washing capabilities and a strong response to carbon dioxide. When combined with carbon dioxide, the system enhances both the rate and efficiency of oil washing. Imbibition recovery can reach more than 50%. The research results provide a certain theoretical basis and data reference for the efficient development of tight reservoirs.

The novel inorganic solidified foam prepared by direct foaming and its characteristics for preventing spontaneous combustion of coal

ABSTRACT To mitigate coal spontaneous combustion disasters caused due to air leakage in coal mines, inorganic solidified foam is widely employed to seal these areas. This study proposes a simplified method for preparing such foam by directly foaming a mixture of water, cement, fly ash, and foaming agent. This new inorganic solidified foam plugging material aims to enhance sealing effectiveness. The research investigates the foaming ability and stability characteristics of different types of surfactants, analyzing their compatibility with cement and fly ash. It identifies that lauramidopropyl surfactant (LX) exhibits the lowest viscosity in the cement-fly ash slurry mix, resulting in superior foaming performance. By studying effects of water-cement ratio and foaming agent concentration on the foaming performance of cement-fly ash slurry mix, it is found that when the water-cement ratio is 0.6 and the foaming agent concentration is 0.5%, the foaming performance of inorganic solidified foam is optimal, yield the highest foaming efficiency with a multiple of 4.33 times and compressive strength of 0.13 MPa, effectively bonding and reinforcing fractured coal bodies to sealing air leakage cracks efficiently. This study contributes to simplifying the preparation equipment and the application processes of inorganic solidified foam, making it more suitable for widespread application in the confined spaces of coal mines, providing a new technical approach for preventing and controlling coal spontaneous combustion in mines.

Variables Affecting the Preparation and Characterization of Axitinib as Oral Niosmoes

Axitinib is anticancer drug act on different solid tumors by inhibtion protein kinase enzyme which is responsible for support the tumors with blood demand. Due to its low solubility, it has low bioavailability when given orally also it is affected by liver metabolism. Axitinib formulated as non-ionic vesicles (niosomes) for the first time to study the effect of different variables on the in vitro behaviour of vesicles in a hope to improve drug oral bioavailability. Niosomal dispersion formulas were formulated by diverse techniques via multiple kinds of surface-active agent (tween also span), cholesterol and dicetyl phosphate then evaluated for visual appearance, efficiency of drug entrapment (EE%), size of the vesicles, poly dispersity index, zetapotential, viscosity, invitro drug release and study the vesicles morphology by FE-SEM. Many variables effect on EE% were studied such as effect of surfactant amount and type, effect of surfactant combination, impact of various ratios of cholesterol, impact of DCP in various amount , effect of preparation method and effect of sonication time. The results showed that the EE% between (50.97%-98.24%), the particle size was found within the range (64.5 nm - 530.79 nm), zeta potential which was between ( -16.6 to -31 mV), polydispersity index (PDI) &lt;1 and viscosity between (584 – 889.6) centipoise. The niosomal dispersion F1 which contained 1:1 weight ratio (span60: cholesterol) was found with high EE% (96.5±0.16%), smallest particle size (64.5±0.5 nm), highest drug release (100%) of drug released at the end of 4 hours and FE-SEM photograph showed that niosomes were spherical with no aggregation and had a smooth surface. The results showed that thin film hydration method with sonication for four minutes was the best method for preparation of axitinib niosomes, the type and amount of surfactants used, cholesterol ratio, stabilizer and the time of sonication had a substantial effect on EE%, the size of the vesicles as well as drug release; which were investigated so as to optimize the niosomal dispersion of anti-tumour drug reaching to an optimum formula that may improve drug bioavailability. Key words: Axitinib, Anticancer, Vesicles, Surfactants, Invitro behaviour, Entrapment efficiency.

Evaluation of a binary amphiphile/solvent mixture for the formulation of an ecological detergent as an alternative for removing fat from natural fiber surfaces

The application of a binary amphiphile/solvent blend composed of a natural surfactant (alkyl polyglucoside) and the green solvent ethyl lactate (EL) as an active component in the formulation of a new ecological detergent has improved the washing process conditions. Foaming properties of the detergent were optimal, with foam stability (R5) values of 76.17% and 78.61% for the best formulations. It is common practice to add substances that can regulate the pH to 9 to enhance the washing efficiency. This was reflected in the results of this study, where pH and the interaction between pH and surfactant type significantly influenced the percentage of residual fat. Currently, commercial detergents recommend a 1% dilution. However, studies have evaluated a 0.5% dilution. Therefore, it opted to evaluate new concentrations of 0.4% and 0.3%. Optimization of the factorial design resulted in dirt removal rates exceeding 91%, while the lowest percentage of residual fat (< 0.37%) was achieved at 25 °C, pH 9, and 0.3% detergent doses without lipase. Furthermore, illustrations of the surface morphology of the washed fibers demonstrated that the samples were not adversely affected by the formulated detergent or the washing process conditions. The alkyl polyglucoside/ethyl lactate binary blend was shown for the first time to exhibit strong interactions, possessing excellent residual fat and soil removal properties, suggesting its potential use in the formulation of green detergents for washing natural and synthetic textile fibers as a replacement for detergents based on ethoxylated fatty alcohols.

Spectrofluorimetric determination of tapinarof via Zn (II) complexation and assessment of its topical dosage application

Topical tapinarof is used to treat plaque psoriasis (a skin disease in which red and scaly patches form are appeared on some areas of the body). The goal of the current research is to establish a facile and rapid fluorimetric technique for tapinarof analysis. The approach relied on the reaction between the drug and zinc ion through metal complexation to produce a highly-fluorescent product. The fluorescence was further enhanced by adding sodium dodecyl sulfate, and it was observed at 542 nm following excitation at 497 nm. With a correlation coefficient of 0.9997, the association between emission intensity and tapinarof concentration was linear between 2.0 and 120 ng mL−1. 1.021 ng mL−1 was the quantitation limit while 0.366 ng mL−1 was the detection limit. The buffer type, pH and concentration, type of surfactant and concentration, and finally the diluting solvent were among the reaction conditions that were closely examined and it was found that the optimum conditions were obtained upon employing teorell-stenhagen buffer optimized at pH 6.0, 1.38 × 10–2 M SDS and distilled water as a solvent are the suitable choice. With great precision and reliability, the drug under study was quantified using this method in ointment formulations. The proposed method's level of greenness was assessed using two methodologies: the analytical greenness metric (AGREE) and the Green Analytical Procedure Index (GAPI), with good recovery results ensuring high efficiency of the proposed approach on analysis of ointment without any interference from additives and excipients.

Effects of Surfactants on the Aggregation of 6,6'-Disubstituted Thiacarbocyanine Dyes in Aqueous Solutions

The aggregation properties of a number of 6,6'-substituted thiacarbocyanine dyes were studied by spectral-fluorescent methods: T-304, T-306, T-307, T-336 and, for comparison, thiacarbocyanine Cyan 2, which has no substituents in the 6,6'-positions, in aqueous buffer solutions and in the presence of various types of surfactants. The method of moments was used to characterize the absorption spectra (band positions, width, shape). Substituents in the 6,6'-positions significantly increase the ability of dyes T-304, T-306, T-307, T-336 to aggregation (dimerization, as well as to the formation of disordered aggregates with broad low-intensity absorption spectra). The introduction of surfactants leads to rearrangement of the spectra associated with the complex nature of the equilibria between monomers and aggregates of various structures (including surfactant molecules, if present), in particular, with a decrease in the contribution of disordered aggregates. However, the decomposition of dimeric aggregates of 6,6'-substituted cyanines is observed only at very high surfactant concentrations (~20 CMC and higher, where CMC is the critical micelle concentration). At the same time, the passing of surfactant concentrations through CMC does not significantly affect the spectral-fluorescent properties of the dyes, which is probably due to rather strong interactions of the dyes with individual surfactant molecules and premicellar associates of surfactants.

Effect of adsorption of different types of surfactants on conglomerate reservoir minerals on chemical oil recovery efficiency

Using surfactants to extract oil, the anionic surfactant Karamay petroleum sulfonate (KPS), the zwitterionic surfactant octadecyl betaine (BS-18) and the nonionic surfactant coconut oil fatty acid diethanolamide (6501) were selected for adsorption experiments with minerals contained in the conglomerate reservoir with different mineral compositions to study the adsorption law of different types of surfactants. Zeolite and montmorillonite, which have the highest specific surface area and zeta potential among the minerals in the conglomerate reservoir, have the most obvious adsorption effect on surfactants, resulting in a large amount of adsorption of KPS and BS-18. The three types of surfactants were then used to conduct physical simulation oil recovery experiments with conglomerate core samples, and the results showed that 6501 had better overall performance, the best adsorption resistance, and a higher degree of recovery in oil recovery experiments, which provided a basis for the selection of surfactants in the process of chemical drive in conglomerate reservoirs.