Sodium Bis 2-ethylhexyl Sulfosuccinate Research Articles

Modification of nickel ferrite nanoparticles by sodium docusate surfactant for superior crystal violet dye removal from aqueous solutions.

In this study, nickel ferrite (NiFe2O4) nanoparticles were synthesized using the Pechini sol-gel method and modified with sodium docusate surfactant. The modified nanoparticles showed an enhanced adsorption capacity of 384.62mg/g for crystal violet dye, compared to 237.53mg/g for unmodified NiFe2O4. Characterization was performed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM) techniques. The adsorption process was spontaneous, exothermic, and followed the Langmuir isotherm and pseudo-second-order kinetic model. Optimal conditions for maximum dye removal were achieved at pH 10, 50min, and 298K. Additionally, the synthesized adsorbents demonstrated excellent regeneration and reusability over five adsorption-desorption cycles with minimal efficiency loss.

Effects of a Revision to the Standard Admission Order Set on Laxative Prescribing for Opioid-Induced Constipation

Purpose: Opioid-induced constipation (OIC) is highly prevalent in patients with cancer-related pain on opioid analgesics and has negative consequences on physical and psychological well-being and quality of life. Oncology clinical practice guidelines recommend the use of osmotic and stimulant laxatives for the prevention and management of opioid-induced constipation, not stool softeners such as docusate sodium. Prescribing practices continue to fall behind these recommendations. Methods: This quality improvement project revised the laxative options available in the standard admission order set in the electronic medical record. Specifically, docusate sodium was removed and replaced with senna and polyethylene glycol 3350. Results: A total of 2,742 patient admissions preintervention were compared to 2,752 admissions postintervention. The number of orders for docusate (p < .001) and docusate-senna (p = .002) orders decreased significantly after the intervention, in addition to the number of OIC diagnoses (p < .001). However, the number of orders for polyethylene glycol (p = .559), senna (p = .582), other laxatives (p = .245), or functional bowel disorder medications (p = .533) did not change significantly. No significant differences were observed in the frequency of laxative orders placed within 24 hours of an opioid order, number of laxatives prescribed at discharge, admissions related to bowel-related complications, or length of stay. Conclusions: Interventions utilizing the electronic medical record can facilitate evidence-based management of OIC. Development of clinical practice guidelines and tailoring these interventions further is needed to adapt this approach at other institutions and sustain practice change.

Transition from a Sponge-Like to a Foam-Like Nanostructure in a Water-Rich L3 Phase: A Confirmation

Early studies on water - n-alkane - ionic surfactant microemulsions provide first hints for the possible existence of a foam-like nanostructure, i.e. a dense packing of polyhedral nanometer-sized water droplets separated by a thin layer of a continuous oil phase. Indeed, we found a foam-like structure in the system water/NaCl - hexyl methacrylate (C6MA) - dioctyl sulfosuccinate sodium salt (AOT). We were able to locate an isotropic one-phase channel, the L3 phase, emanating from the pseudo-binary system water/NaCl - AOT at ambient temperature and extending towards lower NaCl content with increasing oil content. We showed in our previous work that already upon addition of small amounts of oil to the L3 phase the conductivities become very low and the viscosities very high. Freeze fracture electron microscopy allowed us to visualize the anticipated foam-like nanostructure. To complement our previous work, we investigated the structural transition in the L3 channel by NMR self-diffusion measurements. The new data unambiguously confirm the existence of a foam-like structure. Based on this confirmation we offer an explanation for the topological transition to a foam-like structure, which one can also consider as a “super-swollen reverse micellar phase” – the first of its kind reported so far.

Experimental and simulation study of reverse micelles formed by aerosol-OT and water in non-polar solvents.

The formation of reverse micelles by aerosol-OT [sodium bis(2-ethylhexyl) sulfosuccinate] in hydrocarbon solvents, and in the presence of water, is studied using a combination of atomistic molecular-dynamics simulations and small-angle neutron scattering (SANS). There have been many previous studies of aerosol-OT and its self-assembly in both water and non-aqueous solvents, but this work is focused on a combined experimental and simulation study of reverse-micelle formation. The effects of hydration (with water-to-surfactant molar ratios in the range 0-60) and solvent (cyclohexane and n-dodecane) are investigated. A force field is adapted that results in spontaneous formation of reverse micelles starting from completely randomized configurations. The computed dimensions of the reverse micelles compare very favourably with those determined in SANS experiments, providing validation of the simulation model. The kinetics of reverse-micelle formation are studied with a 50-ns, 1.7-million-atom system which contains, in the steady state, about 50 reverse micelles. The internal structures of reverse micelles are characterized with mass density profiles, and the effects of solvent, and the structural crossover from highly structured water to 'bulk' water in the core, are detailed. The corresponding changes in the molecular reorientation times of sequestered water are also determined. Overall, the combination of experiment and simulation gives a detailed picture of reverse-micelle self-assembly and structure.

Effect of CHAPS on the selective synthesis of (S)-n-octyl ibuprofen ester in AOT reverse micelle catalyzed by lipase

CHAPS (3-[(3-cholamidopropyl) dimethylammonio]-1-propane sulfonate), a biocompatible zwitterionic surfactant derived from bile salt, has attracted great attention due to its distinct molecular structure and aggregation behavior. Addition of a low level of CHAPS to AOT (sodium bis(2-ethylhexyl) sulfosuccinate) reverse micelles has been found to be able to enhance the catalytic activity of the solubilized lipase. In this study, the effect of CHAPS on the lipase-catalyzed selective synthesis of (S)-n-octyl ibuprofen ester was investigated in AOT reverse micelles at 37 °C. The results demonstrate that the presence of CHAPS in AOT reverse micelle enhances both the yield and the enantiomeric excess (ee) value of (S)-n-octyl ibuprofen ester, especially at low water content. With 8 mM CHAPS in AOT reverse micelle ([AOT] = 100 mM, [H2O]/[AOT] = 12, pH = 7.0), a 48-hour yield of 34.2 % could be obtained, which is approximately twice that without CHAPS. In addition, the ee value of the product is increased from 89.1 % to 98.2 %. To understand the mechanism of the CHAPS effect, dynamic light scattering, fluorescence emission spectroscopy and Fourier transform infrared spectroscopy techniques were used to characterize the size of the reverse micelle, the conformation of the solubilized lipase and the activity of the bulk water in the reverse micelle. It reveals that at low water content, the addition of CHAPS enlarges the size of AOT reverse micelle, stabilizes the lipase conformation and reduces the nucleophilicity of bulk water in AOT reverse micelle. The synergistic effect of the aforementioned factors results in the improvement of the enzymatic synthesis of the ester. The above research provides scientific support for the lipase-based preparation of chiral acids/alcohols in the reverse micellar system.

Addressing the non‐ideality of an application relevant surfactant mixture within the hydrophilic–lipophilic‐deviation concept

AbstractIn cleaning products, selecting the right surfactants for the specific soil or contamination is crucial. The hydrophilic–lipophilic deviation (HLD) concept serves as a useful formulation tool by describing the interactions between surfactants, oil and water. However, for mixtures of ionic and non‐ionic surfactants, the HLD concept assumes ideal mixing behavior, which does not hold true. Therefore, interactions between different surfactants must be considered. This can be achieved by introducing the interaction term GEX/RT. Evaluating this interaction term using a set of equilibrated surfactant/oil/water (SOW) systems under various conditions is both time‐consuming and resource intensive. This work aims to demonstrate the rapid determination of this interaction term using the dynamic phase salinity inversion (DSPI) method. We determined the phase behavior of a ternary surfactant system, consisting of sodium dioctyl sulfosuccinate, alkyl polyglucoside, and fatty alcohol ethoxylate, through both equilibrated systems and the DSPI method. Differences between the theoretical HLD calculations and actual experiments allowed us to access interaction terms. To validate GEX/RT obtained by DSPI, we employed net‐average‐curvature concept to model the interfacial tension under different conditions. Spinning drop measurements showed excellent agreement between theoretical and measured values, confirming the applicability of DSPI for determining interactions in this surfactant system.

7928 A "PTH-Mediated" Hypercalcemia Of Malignancy

Abstract Disclosure: N. Sekhon: None. R.J. Bingham: None. Background: We present a challenging diagnostic case of a 73-year-old female with PTH-mediated hypercalcemia in the presence of new metastatic uterine cancer. Case: A 73-year-old female with a past medical history of hypertension and abdominal aortic aneurysm was seen in the hospital for hypercalcemia. She endorsed constipation, fatigue, and generalized weakness for the past few weeks. This was the second hospitalization related to hypercalcemia over the period of 10 days. During the previous hospitalization, her admission calcium was 17 mg/dL and was treated with IV fluids, calcitonin, and zoledronic acid. There was a history of intentional weight loss of about 30-40 lbs in the last 3 months by reducing carbohydrate intake. The patient had a 40-pack years of smoking history. There was no family history of calcium disorders or cancers. Home medications included amlodipine 10 mg QD, docusate sodium 100 mg BID, senna 1 tab QHS, and Vit D 5000 U QD. On physical examination, she was hemodynamically stable but appeared confused and lethargic. The rest of the examination was unremarkable. Laboratory results were remarkable for hypercalcemia (Ca: 13.3 mg/dL), hypophosphatemia (Phosphorus: 2.3 mg/dL), and elevated PTH of 418.3 pg/mL (Ref. Range: 18.4-80.1 pg/mL). CT abdomen/ pelvis revealed innumerable ill-defined hypodense lesions throughout the liver concerning metastatic disease and a 5 cm mass in the uterine fundus. The patient was worked up with the view of hypercalcemia related to malignancy. However, PTHrP (PTH-related peptide) came back normal, which was checked twice during both hospitalizations. Liver biopsy showed metastatic high-grade carcinoma highly suspicious for GYN malignancy with negative PTH staining. Imaging studies for localization including CT soft tissue neck and CT 4D parathyroid with and without contrast failed to show any parathyroid lesions. Endometrial biopsy obtained during subsequent hospitalization showed high-grade adenocarcinoma with focal squamous differentiation. Immunohistochemical staining identified scattered positivity for PTH. The patient was managed as per hypercalcemia of malignancy guidelines with IV fluids and denosumab. Discussion: Hypercalcemia of malignancy due to ectopic PTH secretion has been reported in < 1% of cases. Only two endometrial cancer cases with ectopic PTH have been reported in the literature. PTH-mediated hypercalcemia is seen in primary hyperparathyroidism, parathyroid cancers, or ectopic PTH. In all cases of hypercalcemia of malignancy, primary hyperparathyroidism should be ruled out in the presence of elevated PTH. Diagnosing ectopic PTH secretion by tumor can be challenging due to constant changes in cells with metastasis. Conclusion: This is a rare case of endometrial cancer with liver metastasis and ectopic PTH secretion by primary tumor leading to recurrent hospitalizations related to hypercalcemia. Presentation: 6/2/2024

Medication Use Evaluation of Docusate Sodium in Constipation Prophylaxis and Opioid Induced Constipation at the WPB VA HCS Community Living Center.

Docusate sodium's efficacy is widely debated. Several studies on opioid induced constipation (OIC) concluded that docusate sodium vs either placebo or in combination with sennosides provided no benefit. This medication use evaluation aimed to investigate constipation treatment trends within the West Palm Beach VA Healthcare System Community Living Center, and to assess the therapeutic effectiveness of docusate sodium. This was a retrospective review of data extracted from April 1, 2022, to September 30, 2022. Patients were included if they had oral orders for docusate sodium, sennosides, lactulose, and/or polyethylene glycol. Patients without active bowel regimen medications were excluded. Requirements for rescue constipation medication was evaluated. A total of 98 patients were reviewed. Docusate sodium was used in 43% (n = 42/98) of patients. Rescue medications were needed in 58% (n = 22/38) of patients receiving oral docusate sodium. 52% (n = 29/56) of patients without docusate sodium required rescue medications. For OIC treatment, when docusate sodium was added to other bowel regimens, 59% (n = 17/29) of patients needed a rescue medication, while 66% (n = 19/29) of patients without docusate sodium required a rescue medication. Patients on morphine were given the greatest quantity of rescue constipation medications (73%, n = 16/22). Oral docusate sodium did not reduce the requirement for rescue constipation medications in the WPB VAHCS CLC population. When evaluating constipation treatment, docusate sodium may supply minimal benefit and could be identified as nonessential for deprescribing efforts. Morphine was the most constipating opioid used in this patient population, requiring more aggressive bowel regimens.

Osmotic spawning vesicle.

We discovered a cascade vesicle division system driven by osmotic inflation. Binary giant unilamellar vesicles (GUVs) composed of sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and cholesterol (Chol) were subjected to an osmotic pressure difference by encapsulating membrane-impermeable osmolytes (typically sucrose) in an external aqueous solution containing membrane-permeable osmolytes (typically fructose). This simple setup enabled the mother GUVs to repeatedly form small membrane buds and subsequently undergo divisions over several hundred seconds, resulting in the production of approximately 30-300 daughter GUVs from a single mother GUV. The observed morphological change of GUVs is well described by the mechanical balance between membrane bending, membrane tension, and osmotic pressure difference based on the spontaneous curvature model. This "osmotic spawning" behavior of GUVs does not rely on chemical reactions or functional macromolecules. Therefore, this cascade division system is compatible with various chemical systems and has the potential to implement proliferation ability in artificial cells, drug delivery systems, and protocells simply by modifying their membrane compartments and osmolytes.

Anthelmintic efficacy of Fenbendazole and Niclosamide suspensions obtained by liquid phase mechano-chemical treatment

The purpose of the research is to study the anthelmintic efficacy of suspensions based on a combined solid dispersion of Fenbendazole and Niclosamide.Materials and methods. Mechanochemistry methods were used to prepare suspensions of Fenbendazole (FBZ) and Niclosamide (NSM) substances, in particular, liquid phase grinding of substances with additives (licorice extract, polyvinylpyrrolidone (PVP)) in water or in aqueous sodium carboxymethylcellulose (NaCMC) solution. The grinding was conducted in LE-101 roller mill at energy intensity of 1 g for 1 hour at a roll rotation speed of 60–70 rpm. The resulting suspension samples of combined FBZ and NSM dispersions were studied for cestodocidal activity on a laboratory model of hymenolepiosis of white mice that were infected at a dose of 200 infective Hymenolepis nana eggs per animal.Results and discussion. The 100% efficacy of a combined NaCMC-based drug suspension containing FBZ 13 mg and NSM 130 mg in 1 g of suspension was achieved at a dose of 20 mg/kg of NSM and 2 mg/kg of FBZ. The suspension based on licorice extract, NaCMC, and dioctyl sulfosuccinate sodium salt containing FBZ 18.6 mg and NSM 186 mg in 1 g of suspension at the same dose, i.e. 20 mg/kg of NSM and 2 mg/kg of FBZ showed 71.43% efficacy against H. nana. The suspension based on licorice extract and NaCMC containing FBZ 24.6 mg and NSM 246 mg in 1 g of suspension at the same dose showed a 62.0% effect against H. nana. The activity of the basic drug, the FBZ and NSM suspension was 28.58% at this dose without using mechano-chemical treatment.

Chitosan nanoparticles as drug carrier of gentamicin - density functional theory and molecular dynamics simulation studies

To the best of our knowledge, the detailed evaluation of the interaction of gentamicin with chitosan nanoparticles in the absence and presence of Sodium bis(2-ethylhexyl) sulfosuccinate (AOT) surfactant followed by the evaluation of structural, dynamical, and thermodynamic properties was carried out for the first time which helped to understand the relative drug retention and release time in the model drug delivery system. Gentamicin being an unstable drug molecule demonstrated low efficacy against brucellosis as well as considerable toxicity, thus requiring frequent dosing in different forms including a single dose and combination with other antibiotics; however, no satisfactory result was observed. Chitosan is biodegradable and biocompatible which could help overcome drug delivery issues enabling the drug to reach the target site. Our study is based on the investigation of the chitosan-drug systems without and with the surfactant for the evaluation of the structural, dynamical, and transport properties using a combined approach consisting of density functional theory (DFT) calculations and molecular dynamics (MD) simulations. The DFT results showed that increasing the size of the chain consisting of D-glucosamine facilitated its interaction with the drug molecule thus signifying the role of polymer for the drug accommodation. Furthermore, MD simulation results exhibited the interaction of chitosan nanoparticles with the drug molecules via H-bonding and hydrophobic contacts which were enhanced after the addition of the surfactant. The dynamics and thermodynamic data corroborated the structural properties of the drug-nanoparticle interaction which confirmed the perturbation of the simulation system after the addition of the surfactant. The investigation of another two simulation systems based on the polymer constituents, D-glucosamine pointed towards the significance of the polymerization which eventually resulted in nanoparticles thus providing a platform for drug adsorption. The gentamicin-chitosan nanoparticles were further characterized via transport properties in terms of drug diffusion coefficients which served to consider its use in the context of target drug delivery to treat brucellosis.

A Nanofibrous Polypyrrole Membrane with an Ultrahigh Areal Specific Capacitance and Improved Energy and Power Densities.

For conductive polymers to be competitive with carbon-based electrode materials, it is critical to increase their surface area and electroactivity. In this work, a thick nanofibrous polypyrrole (PPy) membrane with communicating interfiber spaces was prepared through one-pot interfacial polymerization for the first time. The electrochemical properties and conductivity of the membrane were studied with cyclic voltammetry, electrochemical impedance spectroscopy, and a four-point probe. Its morphology, chemistry, and thermostability were evaluated by scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The areal specific capacitances measured between 0.0 and 0.8 V at 1 mA/cm2 were 19179, 13264, 7238, and 4458 mF/cm2 for the membranes doped with docusate sodium (AOT), camphor-10-sulfonic acid (β) (CSA), Cl-, and poly(sodium 4-styrenesulfonate) (PSS), respectively. The capacity retentions after 1000 cycles were 83, 74, 67, and 61% for the AOT-, CSA-, PSS-, and Cl--doped membranes, respectively. The Coulombic efficiency was above 99% for all of the membranes. They showed energy densities of 1.7, 1.2, 0.7, and 0.4 mWh/cm2 and power densities of 0.61, 0.75, 0.66, and 0.62 mW/cm2 for the AOT-, CSA-, Cl--, and PSS-doped membranes, respectively. The ultrahigh areal specific capacitance of PPy-AOT is due to its nanofibrous structure. A mechanism has been proposed to explain how this structure is formed based on the role of AOT as the surfactant. This nanofibrous PPy membrane is easy to prepare and metal-free and offers a very high areal specific capacitance, making it an excellent candidate to construct electrodes in pseudosupercapacitors.

Electrical conductivity of stevia rebaudiana-surfactant mixture aqueous solution: Roles of temperature and sugar substitute concentration

The investigation of stevia-surfactant systems is of significant importance for the extraction process of steviol molecules as well as for the formulation of food products. The present study investigates the electrical conductivity of aqueous solutions containing a sugar substitute and surfactant over a temperature range of 25–50 °C. The sugar-substitute, Stevia Rebaudiana, concentration Cs (g/mL), is ranged from 0.047 to 0.6. The surfactant, Sodium bis(2-ethylhexyl) sulfosuccinate (AOT), has a concentration range of 1.4 ≤CAOT (g/L)≤ 6. The degree of ionization in ionic micelles, α, is determined by examining the conductivity of AOT in Stevia-free water, where complete micelle dissociation is observed. In the presence of Stevia Rebaudiana, a significant exponential decay in system conductivity with respect to the concentration of the sugar substitute is observed. Empirical equations were introduced to describe this behavior. The temperature dependence of conductivity is modeled using an Arrhenius equation. We postulate the formation of pseudo-micelles arising from interactions between the sugar substitute and surfactant, characterized by an effective degree of ionization in ionic micelles, αe.

Gold nanoparticle microemulsion films with tunable surface plasmon resonance signal

Composite films were prepared by the dip-coating method. An organosol of Au nanoparticles (6.3±0.4 nm) was used as the reaction mixture. The nanoparticles were stabilized with sodium bis(2-ethylhexyl) sulfosuccinate (AOT). The prepared films were formed of an AOT layer with encapsulated Au nanoparticles (i.e. Au@AOT films). The films demonstrated a stable plasmon effect. The variation of the immersion number of the glass substrate from 1 to 10 allowed the adjustment of the plasmonic properties. The absorption intensity and maximum wavelength of the surface plasmon resonance were found to change from 0.183 to 0.245 and from 529±2 to 539±2 nm, respectively. The plasmonic properties were found to correlate with the film thickness, roughness, and morphology. An increase in the concentration of Au nanoparticles improves the film’s mechanical strength and wettability.

Growth Kinetics and Porous Structure of Surfactant-Promoted Gas Hydrate.

Surfactants present in tiny amounts in the aqueous phase are known to be efficient gas hydrate promoters; yet, the promotion mechanisms are still not fully understood. Understanding and directing those mechanisms is key to the implementation of gas-hydrate-based applications such as gas storage and separation, secondary refrigeration or water treatment, and desalination. In this work, the growth at the water/gas interface and the porous structure of surfactant-promoted methane hydrate are observed by optical microscopy and Raman imaging in glass capillaries used as optical cells. Hollow crystals are continuously generated and expelled from the methane/water meniscus into the water or surfactant solution, where they ultimately form the skeleton of a porous medium filled with the solution. Unprecedented information is gathered over a range of scales from the molecular scale (crystal structure and cage filling) to the mesoscale (crystal morphologies, growth habits and pore sizes) and macroscale (rates and amounts of water and gas converted into hydrate and hydrate porosity). Following an early steady-state growth regime, a sudden order-of-magnitude increase of the conversion rate occurs, which is related to gaseous methane microbubbles being directly incorporated across the meniscus in the aqueous solution and later converted to methane hydrate. An assessment and comparison are made of the mechanisms and performance of two common anionic surfactants known to be efficient gas hydrate promoters, SDS (sodium dodecyl sulfate) and AOT (dioctylsulfosuccinate sodium or AerosolOcTyl). AOT provides a quicker but more limited conversion into hydrate than SDS, suggesting that it is more appropriate for continuous flow processes while SDS is better suited for gas storage applications. Raman spectra reveal that cage filling by methane of structure I methane hydrate is not affected by surfactants.

High energy throughput using photogalvanic solar techniques and environmentally benign chemical system

Solar energy is gradually becoming integrated into households, holding the potential to address energy requirements through technologies like PV cells. Ongoing research is actively exploring diverse methods of harnessing solar power, with Photogalvanic cells emerging as a particularly promising alternative to Photovoltaic cells. The advantage lies in the cost-effectiveness and simplified fabrication, coupled with the capability of power storage. The utilization of the economical Dioctyl sulfosuccinate sodium (DOSS) surfactant, widely employed in industry, has yielded impressive electrical performance. The present investigation presents a reliable photogalvanic system composed of the photosensitizer dye Quinoline Yellow, the reductant Cellobiose, and the surfactant Dioctyl sulfosuccinate sodium (DOSS), all in a highly alkaline solution with platinum and graphite electrodes. The platinum electrode employed is notably small, boasting a surface area of 0.03 cm2, which enhances the diffusion characteristics of the dye molecules, it is contributing to an enhanced electrical performance of the photogalvanic cell. The resulting photogalvanic cell demonstrates superior electrical performance, featuring a maximum potential of 870 mV, a maximum current of 8000 µA, power at PowerPoint of 695 µW, a fill factor of 0.11, and a conversion efficiency of 13.78 %. Spectrophotometric analysis has confirmed the stability of the dye within the electrolyte solution. Additionally, conductometric analysis has revealed that the surfactant Dioctyl sulfosuccinate sodium (DOSS) enhances the electrical conductivity of the electrolyte solution.

Construction of injectable micron-sized polymorphic vesicles for prolonged local anesthesia with weekly sustained release of ropivacaine

Currently, to overcome the short half-life of the local anesthetic ropivacaine, drug delivery systems such as nanoparticles and liposomes have been used to prolong the analgesic effect, but they are prone to abrupt release from the site of administration or have poor slow-release effects, which increases the risk of cardiotoxicity. In this study, injectable lipid suspensions based on ropivacaine-docusate sodium hydrophobic ion pairing (HIP) were designed to significantly prolong the duration of analgesia. The resulting ion-paired lipid suspension (HIP/LIPO) had a micrometer scale and a high zeta potential, which facilitates stable in situ retention. The strong interaction between docusate sodium and ropivacaine was verified using thermal and spectroscopic analyses, and the formation of micron-sized polymorphic vesicles was attributed to the mutual stabilizing interactions between ropivacaine-docusate sodium HIP, docusate sodium and lecithin. The HIP/LIPO delivery system could maintain drug release for more than 5 days in vitro and achieve high analgesic efficacy for more than 10 days in vivo, reducing the side effects associated with high drug doses. The stable HIP/LIPO delivery system is a promising strategy that offers a clinically beneficial alternative for postoperative pain management and other diseases.

Study of self-organization and structural phase transitions in water /AOT / isopropyl myristate biocompatible system

This work reports preparation and characterization of biocompatible sodium bis(2-ethylhexyl) sulfosuccinate (AOT) / water/ isopropyl myristate (IPM) systems. We studied their ability to form various self-organized structures such as microemulsions and liquid crystal templates for producing nanoparticles such as drug delivery vehicles, which play an important role in delivery of various substances. We determined concentration and temperature conditions that allow for forming various structures in this system and characterized the structural phase transition from the microemulsion to liquid crystalline phase, which is important for delivery of bioactive compounds. The parameters of the liquid crystalline phase of the water/AOT/isopropyl myristate system were calculated for the first time in this work. The sizes of microemulsion droplets were determined. To describe molecular motions in the studied microemulsion, self-diffusion coefficients of each component were measured. The values of relative diffusion coefficients demonstrated that reverse microemulsions were observed at AOT concentrations up to 60 % wt. Further increase in surfactant concentration slows down their molecular mobility and results in formation of aggregates with a bimodal size distribution and a subsequent formation of the hexagonal liquid crystalline phase. Geometry of the mesophase and its structure were investigated by X-ray diffraction. The respective phase diagram was plotted and analyzed using the data of polarized light microscopy, dynamic light scattering, and NMR self-diffusion. In this diagram, the areas corresponding to the microemulsion, the liquid crystal phase, and the structural phase transition were identified.The study of the structural phase transition from the microemulsion to liquid crystal will offer a predictive power for characterizing incorporation of drugs and controlling their delivery to target cells. A deeper understanding of the structural changes is necessary to clearly determine the conditions of drug delivery.

Interactions between quercetin and surfactants/solvents

The quercetin/surfactant/solvent systems are investigated using UV–VIS techniques. The reversed micelles (empty and containing water in their core) formed by Dioctyl sodium sulfosuccinate and Tween 60 (surfactants) in 1,4-dioxane and acetone (solvents) have been used to mimic in a simple way certain structural aspects of natural membranes, especially their hydrophobic parts. The micellar solutions were employed to study interactions with quercetin to check its location in micelles. Obtained results allowed to point that the quercetin molecules’ preferred location in studied micelles is palisade layer. Furthermore, the distribution constant, and binding constant values of quercetin in the examined systems have been calculated.

Synthesis of PDMS Chain Structure with Introduced Dynamic Covalent Bonding for High‐Performance Rehealable Tactile Sensor Application

AbstractIn addressing the increasing demand for wearable sensing systems, the performance and lifespan of such devices must be improved by enhancing their sensitivity and healing capabilities. The present work introduces an innovative method for synthesizing a healable disulfide bond contained in a polydimethylsiloxane network (PDMS−SS) that incorporates ionic salts, which is designed to serve as a highly effective dielectric layer for capacitive tactile sensors. Within the polymer network structure, the cross‐linking agent pentaerythritol tetrakis 3‐mercaptopropionate (PTKPM) forms reversible disulfide bonds while simultaneously increasing polymer softness and the dielectric constant. The incorporation of dioctyl sulfosuccinate sodium salt (DOSS) significantly improves the capacitance and sensing properties by forming an electrical double‐layer through interactions between the electrode charge and salt ions at the contact interface. The developed polymer material‐based tactile sensor shows a strong response signal at low pressure (0.1 kPa) and maintains high sensitivity (0.175 kPa−1) over a wide pressure range (0.1–10 kPa). It also maintains the same sensitivity over 10 000 repeated applications of external pressure and is easily self‐healed against mechanical deformation due to the dynamic disulfide covalent bonding, restoring ≈95% of its detection capacity.