Gemini Surfactants Research Articles

Synthesis and surface activity of two novel phosphate silicone surfactants

Two phosphate amphoteric surfactants based on silicone were synthesized. Phosphate Gemini surfactant ((C12P2)2Si2) with disiloxane as bridging group and double-chain surfactant (C12P2Si3) with hydrophobic hydrocarbon chain and trisiloxane were prepared by hydrolysis reaction, Kabachnik-Fields reaction, and quaternization reaction. FT-IR, 1H NMR and TGA confirmed the chemical structure and thermal stability of the synthesised (C12P2)2Si2 and C12P2Si3. The physicochemical behavior at the air–liquid interface was investigated. The results showed that the critical micelle concentration (CMC) values of (C12P2)2Si2 and C12P2Si3 are 0.53 and 0.78 mmol/L, respectively. The two new surfactants had surface tension at CMC equal to approximately 28 mN/m and their surface tension varied with temperature and electrolyte (NaCl, CaCl2, and MgCl2) concentration. At high temperatures and with high concentration electrolytes, they exhibited good air–liquid interfacial activity. In addition, the size of the aggregates of the surfactants in aqueous solutions above CMC was determined by the dynamic light scattering (DLS) measurements.

Effect of Quaternary Ammonium Gemini Surfactant Solution on the Rate Constant of the Ninhydrin–Lysine Reaction

Effect of Quaternary Ammonium Gemini Surfactant Solution on the Rate Constant of the Ninhydrin–Lysine Reaction

Preparation of Cubosomes with Improved Colloidal and Structural Stability Using a Gemini Surfactant.

Cubosomes are nanoparticles with bicontinuous cubic internal nanostructures that have been considered for use in drug delivery systems (DDS). However, their low structural stability is a crucial concern for medical applications. Herein, we investigated the use of a gemini surfactant, sodium dilauramidoglutamide lysine (DLGL), which is composed of two monomeric surfactants linked with a spacer to improve the structural stability of cubosomes prepared with phytantriol (PHY). Uniform nanosuspensions comprising a specific mixing ratio of DLGL and PHY in water prepared via ultrasonication were confirmed by using dynamic light scattering. Small-angle X-ray scattering and cryo-transmission electron microscopy revealed the formation of Pn3̅m cubosomes in a range of DLGL/PHY solid ratios between 1 and 3% w/w. By contrast, cubosome formation was not observed at DLGL/PHY solid ratios of 5% w/w or higher, suggesting that excess DLGL interfered with cubosome formation and caused them to transform into small unilamellar vesicles. The addition of phosphate-buffered saline to the nanosuspension caused aggregation when the solid ratio of DLGL/PHY was less than 5% w/w. However, Im3̅m cubosomes were obtained at solid ratios of DLGL/PHY of 6, 7.5, and 10% w/w. The lattice parameters of the Pn3̅m and Im3̅m cubosomes were approximately 7 and 11-13 nm, respectively. The lattice parameters of Im3̅m cubosomes were affected by the concentration of DLGL. Pn3̅m cubosomes were surprisingly stable for 4 weeks at both 25 and 5 °C. In conclusion, DLGL, a gemini surfactant, was found to act as a new stabilizer for PHY cubosomes at specific concentrations. Cubosomes composed of DLGL are stable under low-temperature storage conditions, such as in refrigerators, making them a viable option for heat-sensitive DDS.

Self-Assembly of the Cationic Gemini Surfactant in Water: From Elastic Gels to Viscoelastic Solutions

Gemini surfactants, composed of two surfactant monomers, are likely to self-assemble into viscoelastic fluids in water at low concentrations. Here, the aggregation behaviors of quaternary ammonium gemini surfactant with a hydroxyl group on the spacer (16-3OH-16) have been studied in the dilute aqueous system by rheological techniques, small angle X-ray scattering (SAXS), scanning electron microscopy (SEM) and other characterizations. At room temperature, the samples behave as elastic gels. The structure and morphology of gels were confirmed by SAXS and SEM characterizations. Due to the hydroxyl group on the spacer of 16-3OH-16, the gels are more stable than those formed by 16-3-16. At high temperature, the gels transform into wormlike micelles and behave as viscoelastic fluids. The obtained results would help to construct complexed fluids with structure tailorable gemini surfactants.

Study on synthesis and properties of novel bisphenyl sulphonate Gemini surfactant based on lignin for enhanced oil recovery

In this study, we successfully synthesized a new bisphenyl sulphonate Gemini surfactant (BPSG) from lignin using a simple method. And a comprehensive evaluation of the physicochemical properties of this BPSG surfactant was conducted, including surface activity, emulsification stability, salinity tolerance, static adsorption, and oil/water interfacial activity. Comparing the BPSG surfactant with commonly used single-chain surfactants like dodecylbenzene sulfonate (SDBS) and lignin sulphobetaine zwitterionic surfactant (LSBA), our results demonstrated that the BPSG surfactant exhibited higher surface activity and superior emulsification stability. Even at a NaCl concentration of 5.0 wt%, the oil-water emulsion prepared by BPSG surfactant remained stable. Furthermore, the BPSG surfactant displayed remarkable interfacial activities and resistance to salt. It effectively reduced the interfacial tension (IFT) between Huabei crude oil and brine to an ultra-low level of 10−3 mN/m without any additional additives. And the BPSG surfactant showed enhanced alkali synergy compared to common surfactants and maintained the ultra-low oil/water IFT across a wide range of salinity levels. The static adsorption experiments revealed that BPSG had significantly lower adsorption amount on the quartz sand compared to ordinary surfactants, allowing for the sustained achievement of ultra-low IFT during the adsorption process for up to four consecutive days.

Gemini surfactant‐stabilized Pd nanoparticles: Synthesis, characterization, and catalytic application in the reduction and reductive acetylation in the water solvent

A series of Gemini surfactants (GSs) were prepared by reacting alkyl bromides with N,N,N′,N′‐tetramethyl ethylenediamine. Various alkyl bromides used in for the preparation of GSs are 1,3‐dibromo ethane, 1,3‐dibromoethane, 1‐Bromohexane, 1‐Bromooctane, 1‐Bromooctadecane and 1‐Bromooctadodecane. Different solvents and temperatures were investigated for the formation of gels of prepared GSs. Among all, 1‐Bromooctane, 1‐Bromooctadecane‐derived GSs formed organogels. Thus, synthesized long‐chain organogels have been used to stabilize Pd NPs. The Pd NPs formation initially confirmed through Ultraviolet‐visible, Scanning Electron Microscopy, and Atomic Force Micrograph studies. Later Fourier Tansform Infra Red, Thermo Gravimetric Analysis, and Zeta potential studies were also carried out to understand their properties extensively. The Pd NPs stabilized by GSs have been identified as a potential catalyst in the reductive N‐acetylation of nitroaromatics at room temperature. The N‐acetylated products were obtained in good yields in an aqueous medium. In addition, the potentiality of our catalyst has been also evaluated in the reduction of nitroaromatics in an aqueous medium, which is a green protocol. Further, the semi‐empirical geometry optimizations of active GS gel confirmed the dihedral angle of 59° in between the two octyl moieties calculated from computational studies. The rheological properties such as amplitude sweeping, viscosity shear profile of the gel have also been studied.

The structure effect on the physicochemical properties of Gemini surfactants used as viscosity reducer for heavy oil

The structure of surfactants is a key factor affecting their physicochemical properties. Our earlier work synthesized Gemini surfactants CEA-n with different structures. In this paper, the effects of polyether chain length, spacer groups number and the hydrophobic alkyl chain length of surfactants CEA-n on the interfacial properties, wettability, rheological properties and emulsion stability were fully studied in detail, and the effects of surfactant structure on their temperature tolerance and salt resistance properties were explored. The results showed that the variation of polyether chain length of surfactant molecules had the greatest impact on the interfacial tension (IFT), and the surfactants with longer alkyl chains had better interfacial film strength. The wettability of various surfactant systems was investigated by the sessile drop method, and the contact angle decreased remarkably from 92.6° to 17.9° in a short time (300 s) after adding surfactant CEA-6. Judging from the fluid type, each heavy oil emulsion system exhibited pseudoplastic fluid characteristics, and dilute shear phenomenon was observed in the range of 0–50 s−1 with an increasing shear ratio. The particle size, dispersibility and coalescence of the heavy oil O/W emulsion droplets of each system were observed through the microscopic images of the emulsions, and the factors affecting the stability of the emulsions were systematically studied by bottle test. It was found that the increase of oil-water ratio, surfactant concentration and mixing speed would improve the stability of O/W emulsions, while high temperature would accelerate the demulsification process. All these results established the structure-property relationship of surfactant molecules.

Synthesis and properties of amide-based cationic gemini surfactants with semi-rigid spacer

Abstract A series of novel gemini surfactants (m-E2Ph-m) with ester groups and a benzene ring as rigid spacer were synthesized and characterized by IR, 1H NMR and Mass spectrometry. The effect of hydrophobic chain length on the surface properties and aggregation behavior of the gemini surfactants were investigated by the measurements of surface tension, electrical conductivity, fluorescence. The critical micelle concentration (CMC) of these surfactants decreases with increasing alkyl chain length. The thermodynamic parameters exhibited that the micellization was a spontaneous and exothermic process in environment. The micellization process became more beneficial with the increase of alkyl chain length and the decrease of temperature.

Effect of in situ mixed micellization of ester-functionalized gemini surfactant at different pHs on solubilization and cosolubilization of various polycyclic aromatic hydrocarbons of varying hydrophobicities

A pH controlled cleavability unfolds the 3-in-1 surfactant feature of an ester-bonded gemini surfactant, 2, 2’-[(oxybis (ethane-1,2-diyl))bis (oxy)]bis (N-hexadecyl-N,Ndimethyl-2-oxoethanaminium) dichloride (C16–C4O2–C16), by reinforcing in-situ mixed micellization between cleaved components at non-neutral pH (pH 3,12). The triplicity is assigned to two mixed-micelle variants at pH 3 and pH 12 besides the unhydrolyzed C16–C4O2–C16 at pH 7. The pH-controlled aggregation of such trichotomic surfactant dramatically enhances the micellar solubilization/cosolubilization of PAHs viz. naphthalene (Np), phenanthrene (Ph), pyrene (Py), perylene (Pe). The cosolubilization of binary/ternary PAH mixtures in such remarkable micellar assemblies at pH 3, 7 and 12 yields intriguing synergistic or antagonistic solubility outcomes correlated to PAH-PAH and PAH-micelle interactions. This study provides valuable insights into the potential applications of the ester-bonded gemini surfactant for the cosolubilization of undesirable hydrophobic compounds at natural sites having variable pH.

Excellent condensate and salt‐resistant foam by anionic‐zwitterionic‐cationic Gemini surfactants compounds for gas well deliquification

AbstractThe blockage caused by liquid loading poses a major problem to the aged gas wells. Various categories of foaming surfactants including zwitterionic, anionic and cationic surfactants are often used for foam‐based gas well deliquification. In this study, a foaming formula containing anionic (sodium lauroyl sarcosinate, LSS), cationic Gemini (C16AGB and C12AGB) and zwitterionic (C16APB and C12APB) surfactants was developed. This foaming formula was first optimized through the foaming ability and foam stability tests, and then evaluated through liquid unloading performance tests under various salinity, condensate, methanol and temperature conditions. Synergy was observed in the foaming ability and foam stability measurements when LSS, C16AGB, C12AGB, C16APB and C12APB were combined at a molar ratio of 5:4:1:4:1. The foaming formula exhibited excellent liquid unloading performance at high salinity (up to 26 × 104 mg/L), high condensate fraction (up to 25%) and high methanol fraction (up to 50%) conditions. The presence of 10% methanol significantly enhanced foaming efficiency (referred to as the ratio of the foam mass to the initial liquid mass) and liquid unloading efficiency of the foaming formula at 20–90°C. Furthermore, the surface tension measurements and the foam morphological investigation were carried out to reveal the observed synergy.

Compaction of Calf Thymus DNA by a Potential One-Head-Two-Tail Surfactant: Properties of Nanomaterials and Biological Testing for Gene Delivery.

A one-head-two-tail cationic surfactant, Dilauryldimethylammonium bromide (DDAB) has shown a great extent of calf thymus DNA (ct-DNA) compaction being adsorbed on the surfaces of negatively charged SiO2 nanoparticles (NPs). DDAB molecules show high adsorption efficiency and induce many positive surface charges per-unit surface area of the SiO2 NPs compared to cationic Gemini (12-6-12) and conventional (DTAB) surfactants in an aqueous medium at pH 7.4, as evident from zeta potential and EDAX data. Transmission electron microscopy and field emission scanning electron microscopy images, along with ethidium bromide exclusion assay and DLS data support the compaction of ct-DNA. Fluorescence microscopic images show that in the presence of SiO2 NPs, DDAB can perform 50% compaction of ct-DNA at a concentration ∼58% and ∼99% lower than that of 12-6-12 and DTAB, respectively. Better ct-DNA compaction by DDAB is evident compared to other Gemini surfactants (12-4-12 and 12-8-12) as well reported before. Time-correlated single photon counting fluorescence intensity decay measurements of a probe DAPI in ct-DNA have revealed the average lifetime value that is decreased by ∼61% at 2.5 μM of DDAB in the presence of SiO2 NPs as compared to a decrease by only ∼29% in its absence, supporting NPs-induced stronger surfactant binding with ct-DNA. Fluorescence lifetime data have also demonstrated the crowding effect of NPs. At 2.5 μM of DDAB, both fast and slow rotational relaxation components of DAPI contribute almost equally to depolarization with the absence of NPs; however, with the presence of NPs, ∼96% weightage of the anisotropy decay is for the fast component. The present DDAB-SiO2 NPs combination has proved to be an excellent gene delivery system based on the cell viability in the mouse mammary gland adenocarcinoma cells (4T1) and human embryonic kidney (HEK) 293 cell lines, and in vitro and in vivo studies.

Properties and Applications of Quaternary Ammonium Gemini Surfactant 12-6-12: An Overview.

Surfactants are amphiphilic molecules and one of the most versatile products of the chemical industry. They can be absorbed at the air-water interface and can align themselves so that the hydrophobic part is in the air while the hydrophilic part is in water. This alignment lowers the surface or interfacial tension. Gemini surfactants are a modern variety of surfactants with unique properties and a very wide range of potential applications. Hexamethylene-1,6-bis(N-dodecyl-N,N-dimethylammonium bromide) is one such representative compound that is a better alternative to a single analogue. It shows excellent surface, antimicrobial, and anticorrosion properties. With a highly efficient synthetic method and a good ecological profile, it is a potential candidate for numerous applications, including biomedical applications.

Cationic-anionic surfactant mixtures based on gemini surfactant as a candidate for enhanced oil recovery

The surface and interfacial properties of bisquaternary ammonium salts (16−4−16), sodium dodecyl benzene sulfonate (SDBS), and their mixture were investigated. Moreover, the effects of adsorption on the crude oil/water interfacial tension (IFT) of the SDBS/16–4–16 mixture were examined. Finally, the wettability alternation, oil film peeling-off performance, and core flooding were used to evaluate the enhanced oil recovery of the SDBS/16–4–16 mixture. Results show that the cationic Gemini surfactant 16–4–16 exhibits a strong synergistic effect with SDBS in surface/interfacial activity. At αSDBS = 0.66, the CMC value of the SDBS/16–4–16 mixtures reaches the lowest (0.016 mmol/L), and the interaction parameter (βm) exhibits a minimal value (−11.47), indicating a strong attraction between the cationic and anionic surfactants. When αSDBS is between 0.2 and 0.7, the diesel/water IFT is reduced below 10−2 mN/m, and the IFT shows little relationship with the mixing ratio. For crude oil, when αSDBS is equal to 0.4 and 0.5, the SDBS/16–4–16 mixtures can also reduce the crude oil/water IFT to ultra-low (<10−2 mN/m). When the mineralization is between 5000 mg/L and 20,000 mg/L, the IFT of crude oil/water can be reduced to 3.3 × 10−3 mN/m.Adsorption time, temperature, and liquid-solid ratio have less effect on the IFT of the SDBS/16–4–16 mixture (αSDBS = 0.4) than cationic surfactant 16–4–16. As static adsorption time increases to 24 h, the IFT of the SDBS/16–4–16 mixture only increases from 3.13 × 10−3 mN/m to 4.58 × 10−3 mN/m, while 16–4–16 increases the IFT from 0.121 mN/m to 0.202 mN/m. Furthermore, the SDBS/16–4–16 mixture takes only 10 min to reach dynamic adsorption equilibrium, shorter than the two pure components. The ability of the SDBS/16–4–16 mixtures to reduce the contact angle on the lipophilic glass surface and the oil film peeling-off performance is significantly superior to 16–4–16 and SDBS. As low as 0.1 mmol/L, the SDBS/16–4–16 mixture (αSDBS = 0.4) can reduce the contact angle of oil-wet glass surface from 107° to 46°, while 16–4–16 reduces it to 68° and SDBS to 79°. Eventually, the SDBS/16–4–16 mixture (αSDBS = 0.4) shows excellent performance in the core flooding experiments. The SDBS/16–4–16 mixture could improve crude oil recovery by 26.2%, demonstrating great potential in EOR.

New anionic Gemini surfactant viscoelastic fluid for clean fracturing of natural gas hydrate

In this work, the properties of a new anionic Gemini surfactant (AGn) and its application in natural gas hydrate fracturing fluid are studied. The surface properties of AGn were investigated and the formulations of AGn / NH4Cl and AGn / TMBAC (Benzyltrimethylammonium chloride) systems were optimized. The temperature and shear resistance, shear recovery, viscoelasticity, and fracturing performance of the optimized system were evaluated. The results showed that AGn exhibits excellent surface activity and can spontaneously form worm-like micelles in aqueous solution. The optimized fracturing fluid system formulations were 1.5% AG16 + 0.4% NH4Cl and 1.5% AG16 + 0.4% TMBAC. The system had good rheological properties, outstanding filtration, and excellent sand suspension performance, and could complete gel breaking in a 4% NaCl environment. It was suggested that the AGn-based fracturing fluid system has the potential to meet the fracturing requirements of natural gas hydrate fracturing operations and has potential application prospects.

Empirical and Computational Investigation of Cationic Gemini Surfactants as Anti-Corrosive Inhibitors for Mild Steel in Acid Medium and its silver Nano Structure synthesis and Analysis.

Empirical and Computational Investigation of Cationic Gemini Surfactants as Anti-Corrosive Inhibitors for Mild Steel in Acid Medium and its silver Nano Structure synthesis and Analysis.

Self-aggregation of cationic gemini surfactants with amide groups in the spacer and variable alkyl chain length

AbstractSynthesis, aggregation parameters and antimicrobial activity of novel cationic gemini surfactants with two amide groups in gemini spacer structure and a variable number of carbon atoms in alkyl tails ranging from 12 to 15 are reported. The critical micelle concentration of gemini surfactants was determined using surface tension and electrical conductivity methods. The cmc values were found in the range 0.83 to 0.06 mM. The interfacial area, micelle ionisation degree and the Gibbs free energy per molecule and alkyl chain were calculated from the surface tension and conductivity curves. Particle size analysis using the dynamic light scattering method confirmed the formation of small spherical micelles 6–7 nm large in size for gemini surfactants with 12 and 13 carbon atoms in the alkyl chain. A large size above 50 nm was found for the aggregates composed of long-chain gemini molecules with 14 and 15 carbon atoms. The zeta potential of gemini surfactants shows a continuous increase with the increasing alkyl chain length. Micelle aggregation number of gemini surfactants correlates well with the hydrodynamic size data. Small aggregation number values were found for short-chain gemini molecules with 12 and 13 carbon atoms in the alkyl chain. Long-chain gemini molecules with 14 and 15 carbon atoms exhibit aggregate growth represented by an increase in the aggregation number values while maintaining the spherical or spheroidal shape of micelles. The investigations of antimicrobial activity against Gram-positive bacteria, Gram-negative bacteria and yeast indicate the increasing antimicrobial efficiency towards the short-chain surfactant with 12 carbon atoms in the alkyl chain. A possible cut-off effect presence is proposed to explain the dependence of antimicrobial activity on the surfactant alkyl tail length.

Mixed Aggregates of Surface-Active Ionic Liquids and 14-2-14 Gemini Surfactants in an Aqueous Medium as Fluid Scaffolds for Enzymology of Cytochrome-c.

The aggregation behavior of the surface-active ionic liquid (SAIL), 3-(2-(hexadecyloxy)-2-oxoethyl)-1-methyl-1H-imidazol-3-ium chloride, [C16Emim][Cl], and a gemini surfactant (GS) (14-2-14) in the whole mole fraction range has been investigated in an aqueous medium employing various techniques. Experimentally obtained values of critical aggregation concentration (cac) are in good agreement with the theoretical cac values obtained using Clint's equation. Rubingh's model has been employed to evaluate the extent of synergistic interactions between two components, which has been found to be dependent upon the composition of a mixture of surfactants. The polarity index, hydrodynamic diameter (Dh), zeta potential (ζ-Pot.), and morphology of the aggregates have been found to be dependent upon the extent of hydrophobic as well as dipolar interactions and the degree of counterion binding governed by the content of the GS in mixed aggregates. Thermodynamic parameters evaluated employing isothermal titration calorimetry have revealed the aggregation as an entropy-driven process. Density functional theory calculations provide a detailed account of the SAIL-GS interactions at the molecular level. The reduced density gradient (RDG) along with the calculated isosurfaces asserts that the dominant interactions are noncovalent interactions. Furthermore, the enzymology of cytochrome-c in the aqueous SAIL-GS aggregated systems has been investigated and a two-fold increase in the enzyme activity has been observed in the aggregates formed by the GS as compared to that in buffer.

Relationship between Dynamic Interfacial Tension and Ultimate Recovery in Gemini Surfactant Flooding: An Exploration through Fractured Micromodels

Relationship between Dynamic Interfacial Tension and Ultimate Recovery in Gemini Surfactant Flooding: An Exploration through Fractured Micromodels

Experimental and Computational Characterization of the Molecular Interaction between Bovine Serum Albumin and an Ester‐functionalized Cationic Gemini Surfactant

AbstractIn view of the recent emergence of surfactants as therapeutic agents for industrial‐based pharmacology, the current study highlights the critical aspects of a cationic C12−E2O2−C12 gemini surfactant, such as pharmacodynamics and pharmacokinetics. Surface tension, fluorescence and absorption studies reveal that the gemini surfactant interacts efficiently with the BSA. The Stern‐Volmer and Benesi‐Hildebrand equations, utilized to compute the binding constants (KSV and Kb), evaluated at three temperatures by utilizing fluorescence quenching data, provide evidence of static quenching and the evaluated thermodynamic parameters (which are all negative) suggest a spontaneous complexation with the pivotal role being played by both van der Waals forces and hydrogen bonds. Other complementary methods (3‐D, synchronous, RRS, CD, FT‐IR) confirmed conformational alterations in BSA due to the interaction. Binding of the C12−E2O2−C12 gemini surfactant within the protein's site I (sub‐domain IIA) had been derived from site probe and molecular docking analyses. Also, the HOMO‐LUMO energies, band gap energy and global reactivity descriptors of C12−E2O2−C12 gemini surfactant and the aromatic residues of BSA were evaluated. The study might help use C12−E2O2−C12, gemini surfactant as a therapeutic agent in the pharmaceutical industry.

Synthesis, Properties, and Biomedical Application of Dicationic Gemini Surfactants with Dodecane Spacer and Carbamate Fragments.

A synthesis procedure and aggregation properties of a new homologous series of dicationic gemini surfactants with a dodecane spacer and two carbamate fragments (N,N'-dialkyl-N,N'-bis(2-(ethylcarbamoyloxy)ethyl)-N,N'-dimethyldodecan-1,6-diammonium dibromide, n-12-n(Et), where n = 10, 12, 14) were comprehensively described. The critical micelle concentrations of gemini surfactants were obtained using tensiometry, conductometry, spectrophotometry, and fluorimetry. The thermodynamic parameters of adsorption and micellization, i.e., maximum surface excess (Гmax), the surface area per surfactant molecule (Amin), degree of counterion binding (β), and Gibbs free energy of micellization (∆Gmic), were calculated. Functional activity of the surfactants, including the solubilizing capacity toward Orange OT and indomethacin, incorporation into the lipid bilayer, minimum inhibitory concentration, and minimum bactericidal and fungicidal concentrations, was determined. Synthesized gemini surfactants were further used for the modification of liposomes dual-loaded with α-tocopherol and donepezil hydrochloride for intranasal treatment of Alzheimer's disease. The obtained liposomes have high stability (more than 5 months), a significant positive charge (approximately + 40 mV), and a high degree of encapsulation efficiency toward rhodamine B, α-tocopherol, and donepezil hydrochloride. Korsmeyer-Peppas, Higuchi, and first-order kinetic models were used to process the in vitro release curves of donepezil hydrochloride. Intranasal administration of liposomes loaded with α-tocopherol and donepezil hydrochloride for 21 days prevented memory impairment and decreased the number of Aβ plaques by 37.6%, 40.5%, and 72.6% in the entorhinal cortex, DG, and CA1 areas of the hippocampus of the brain of transgenic mice with Alzheimer's disease model (APP/PS1) compared with untreated animals.