Mixed Micellar System Research Articles

Rationalizing the Design of Pluronics-Surfactant Mixed Micelles through Molecular Simulations and Experiments.

Aqueous systems comprising polymers and surfactants are technologically important complex fluids with tunable features dependent on the chemical nature of each constituent, overall composition in mixed systems, and solution conditions. The phase behavior and self-assembly of amphiphilic polymers can be changed drastically in the presence of conventional ionic surfactants and need to be clearly understood. Here, the self-aggregation dynamics of a triblock copolymer (Pluronics L81, EO3PO43EO3) in the presence of three cationic surfactants (with a 12C long alkyl chain but with different structural features), viz., dodecyltrimethylammonium bromide (DTAB), didodecyldimethylammonium bromide (DDAB), and ethanediyl-1,2-bis(dimethyldodecylammonium bromide) (12-2-12), were investigated in an aqueous solution environment. The nanoscale micellar size expressed as hydrodynamic diameter (Dh) of copolymer-surfactant mixed aggregates was evaluated using dynamic light scattering, while the presence of a varied micellar geometry of L81-cationic surfactant mixed micelles were probed using small-angle neutron scattering. The obtained findings were further validated from molecular dynamics (MD) simulations, employing a simple and transferable coarse-grained molecular model based on the MARTINI force field. L81 remained molecularly dissolved up to ∼20 °C but phase separated, forming turbid/translucent dispersion, close to its cloud point (CP) and existed as unstable vesicles. However, it exhibited interesting solution behavior expressed in terms of the blue point (BP) and the double CP in the presence of different surfactants, leading to mixed micellar systems with a triggered morphology transition from unstable vesicles to polymer-rich micelles and cationic surfactant-rich micelles. Such an amendment in the morphology of copolymer nanoaggregates in the presence of cationic surfactants has been well observed from scattering data. This is further rationalized employing the MD approach, which validated the effective interactions between Pluronics-cationic surfactant mixed micelles. Thus, our experimental results integrated with MD yield a deep insight into the nanoscale interactions controlling the micellar aggregation (Pluronics-rich micelles and surfactant-rich micelles) in the investigated mixed system.

Strategic application of a mixed polymeric micellar solid dispersion system to domperidone for improved biopharmaceutical characteristics

Strategic application of a mixed polymeric micellar solid dispersion system to domperidone for improved biopharmaceutical characteristics

Comparative studies on the aggregate formation of synthesized zwitterionic gemini and monomeric surfactants in the presence of the amphiphilic antipsychotic drug chlorpromazine hydrochloride in aqueous solution: an experimental and theoretical approach.

The formation of aggregates, which are widely used in the field of biochemistry and the medical industry, was studied with different compositions of alkyl betaine gemini surfactant (C14Ab) in conjugation with chlorpromazine hydrochloride (CPZ). The results were compared with those of a single-chain zwitterionic surfactant (C12DmCB) of the same type with CPZ. Dynamic light scattering (DLS), confocal laser scanning microscopy (CLSM), and transmission electron microscopy (TEM) methods were used to distinguish the aggregates for the CPZ/C14Ab system in aqueous solutions above a certain mole fraction of the drug CPZ (αCPZ = 0.2). Time-resolved fluorescence decay measurements of acridine orange revealed relative polarity near the head group regions of mixed micelle (CPZ/C14Ab and CPZ/C12DmCB) systems. The hydrophilic environment around the head group regions of the CPZ/C14Ab system was different from that in the case of the CPZ/C12DmCB system. On the other hand, several theoretical models were employed (Clint, Rubingh, Motomura, and SPB) for mixed micellar systems to elucidate the different interaction parameters. Such a systematic study of a zwitterionic gemini amphiphile and its interaction with other amphiphiles and an amphiphilic drug molecule is rare in the literature.

Extending the Pseudo-Phase Model of Detergent–Lipid Dispersions by a Detergent-Binding Protein

Mixed micellar drug delivery systems for poorly soluble active pharmaceutical ingredients (APIs) are easy to produce and long-term stable, because they represent equilibrium structures. However, their fate after intravenous injection is still largely unknown. Once injected into the bloodstream, they can potentially convert to vesicles or disappear altogether, with both API and excipients being picked up by blood components. Our study aimed at reducing the gap between the good, quantitative understanding of aqueous glycocholate (GC)-lecithin dispersions alone and the highly complex situation in the blood. To this end, we extended the pseudophase model previously established for lipid-detergent dispersions to include the detergent-binding protein albumin as another component. The model predicted a quaternary phase diagram with planar phase boundaries defined by key parameters of the ternary subsystems, which were then determined by isothermal titration calorimetry. They include the aqueous GC concentration upon bilayer-micelle coexistence, 5.2 mM, the GC-to-lipid mole ratios in coexisting bilayers (Resat = 0.2) and micelles (Resol = 0.7), as well as the capacity of the albumin to bind 0.1 GC molecules with a dissociation constant of KD = 0.1 mM and 6 GC molecules with KD = 0.7 mM. Subsequent measurements in the quaternary system showed phase boundaries in good agreement with the model predictions. In addition, the critical micelle concentration of GC shows a minimal value (midpoint of transition) of 9.1 mM at the temperature of 24 °C where the demicellization enthalpy is zero. The demicellization process is accompanied by a heat capacity change of 29 cal/mol K. The model improves the understanding of the mixed micellar drug delivery systems. The success of the approach encourages including even more blood components, like lipoproteins, to a quantitative treatment.

Application of anionic-nonionic mixed micellar system for solubilization of methylene blue dye

Present study highlights the interaction of methylene blue (MB), a cationic dye, with anionic surfactant, sodium dodecyl sulfate (SDS), and its mixed micelles with a nonionic surfactant Triton X-114 (TX-114). The results obtained from UV–visible spectrophotometry were used to obtain the degree of solubilization in terms of binding constant (Kb) and partition coefficient (Kx) of dye in single and mixed micellar systems (MMS). Gibb’s free energies of partitioning and binding were also calculated for both systems. Specific conductance was measured to determine the CMC of single and mixed micellar media at five different temperatures, T = (293.15 – 333.15) K. Temperature-dependent thermodynamic parameters like Gibb’s free energy of micellization (ΔGomic), enthalpy of micellization (ΔHomic), and entropy of micellization (ΔSomic) were calculated using data of specific conductance measurements. Effect of concentration of TX-114 on Kx and Kb values of the MB in MMS is also investigated. Spectroscopic and conductometric results revealed that the anionic-nonionic mixed micellar system was better and more effective for the removal and solubilization of MB from aqueous system as compared to anionic micelles only. However, it has been observed that after a critical concentration an increase of non-ionic surfactant concentration has a reverse effect on solubilizing power of ionic-nonionic mixed micellar system. This indicates that the dye-surfactant interaction became weaker due to possible decrease in ionic character of mixed micelles when the high fraction of TX-114 was used.

Mixed Micellar Solubilization of Naphthol Green B Followed by Its Removal from Synthetic Effluent by Micellar-Enhanced Ultrafiltration under Optimized Conditions.

In this manuscript, the application of cetyltrimethylammonium bromide (CTAB) and cetylpyridinium chloride (CPC) for the removal of Naphthol Green B (NGB) as a synthetic effluent has been studied. The solubilization of NGB by a single and mixed micellar system using Triton X-100 (TX-100) as a nonionic surfactant has been performed to establish both the extent of the partitioning (kx) of NGB and ultimately their respective Gibbs free energies ΔGp as well. An applied methodology, micellar-enhanced ultrafiltration (MEUF), has also been studied in different micellar media of cationic surfactants by variation in some selective parameters, such as the concentration of surfactant, electrolyte, pressure, pH, and RPM to obtain optimum conditions. The results have been analyzed by a UV/visible double beam spectrophotometer. ΔGp was found to be −39.65 kJ/mol and −47.94 kJ/mol by CTAB and CPC, respectively, in the presence of a nonionic surfactant. The maximum value of Gibbs free energy (ΔGp) of the partition was obtained by CPC. The values of the rejection coefficient (R%) and permeate flux (J) are also calculated. A maximum removal of 99.77% and 98.53% by CTAB and CPC, respectively, was obtained. It has been observed that both of the surfactants are strong candidates for NGB removal.

Mixed micellar systems — efficient nanocontainers for the delivery of hydrophobic substrates

Mixed micellar systems — efficient nanocontainers for the delivery of hydrophobic substrates

Loading of hydrophobic drug silymarin in pluronic and reverse pluronic mixed micelles

In the presented work, pure pluronic and mixed micelles of normal pluronics (F108, F127, P85 and P84) with reverse pluronic (10R5) have been studied to enhance the solubilization of the hydrophobic drug silymarin (SLY) at different % w/v proportions (4:1, 2.5, 1:4 and 5). Solubilization capacity of SLY in the mixed micelles was found to be higher than pure pluronic micelles. Drug solubilization parameters including drug loading efficiency (DL), partition coefficient (P) and Gibbs free energy of solubilization (ΔG◦) were calculated. SLY loaded mixed micellar formulation of P84:10R5 (4:1% w/v) showed maximum solubility and drug loading efficiency as compared to other mixed micellar formulations. The cmc of pure as well as mixed micellar systems has been evaluated using fluorescence measurements. The locus of SLY in these micelles was evaluated by micropolarity measurements. After solubilization, increase in hydrodynamic size evidenced by DLS measurements confirmed the solubilization of SLY in the mixed micelles. In vitro drug release study was also performed for mixed micellar formulations with maximum SLY solubilization, and it was found to exhibit sustained release drug behavior. Different kinetics models were also applied and the best fitted model for the optimum SLY loaded mixed micellar formulation was found to be the Korsmeyer-Peppas model. To investigate the anti-oxidative potential of SLY drug and SLY loaded mixed micellar formulation of P84:10R5 (4:1% w/v),1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH·) scavenging, ferrous ions (Fe2+) chelating activities, total reducing ability determination by Fe3+ to Fe2+ transformation method, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging and nitric oxide assay were undertaken. The SLY loaded mixed micellar formulation of P84:10R5 (4:1% w/v) exhibited appreciably enhanced anti-oxidative activity as compared to SLY alone.

Multi-technique approach to explore the mixed micellization behavior of promazine hydrochloride drug and cetyltrimethylammonium bromide surfactant in aqueous glycine, glycylglycine (dipeptide) and glycylglycylglycine (tripeptide) solutions

The aggregation properties of amphiphiles and their mixtures are of theoretical and applied importance. Therefore, mixed micellization behavior of promazine hydrochloride (PMZ) drug and cetyltrimethylammonium bromide (CTAB) surfactant at different mole fractions, α PMZ = (0.2, 0.4, 0.6 and 0.8) has been scrutinized in water and (0.025, 0.050 and 0.100) mol·kg −1 aqueous solutions of glycine, glycylglycine (dipeptide) and glycylglycylglycine (tripeptide) at T = (298.15 to 318.15) K, by means of multiple techniques. Thermodynamic parameters of micellization (ΔG°m, ΔH°m, and ΔS°m) along with excess Gibbs free energy of mixing (ΔG m ex), the molecular interaction parameter (β int), and the degree of ionization (α), have been attained from the conductivity measurements. The partial specific volumes (φ v), partial specific isentropic compression (φ κ) as well as isentropic compressibilities (κ s) were computed from the measured density and speed of sound data. UV-Visible absorption, fluorescence emission and proton (1H) NMR spectra were recorded for the pure PMZ and mixed (PMZ + CTAB) system in the presence of glycine(aq), glycylglycine(aq) and glycylglycylglycine(aq) solutions. Dynamic light scattering (DLS) study was carried out to measure the hydrodynamic diameters (D H) of mixed micellar systems. The prevalence of hydrophobic-hydrophobic interactions amid the hydrophobic groups of PMZ drug (tricyclic scaffolding), CTAB (–C16H33), glycine, di- and tri-peptides (–CH2), and electrostatic interactions amid the hydrophilic/ionic groups of PMZ{tertiary amine part and +NH (CH3)2, Cl−}, CTAB (–N (CH3)3 +, Br‒) and glycine, di- and tri-peptides {zwitterion (NH3 +, COO−} have been depicted from the aforementioned studies.

Effect of drug aceclofenac on physicochemical properties of mixed micellar systems

In this article, the effect of the drug aceclofenac (ACF) on the properties of three mixed micellar systems are studied. The three systems were pluronic L64 + F127 (nonionic-nonionic), pluronic L64 + CTAB (cetyltrimethyl ammonium bromide), (nonionic-cationic) and L64 + SDS (Sodium dodecyl sulphate), (nonionic-anionic) combinations. The physicochemical parameters were characterized by different techniques such as UV visible spectroscopy, FTIR, conductance, DLS, and SEM. The presence of ACF affected the nonionic-ionic mixed micelles more than the nonionic-nonionic group as evidenced by UV spectroscopy. From the DLS measurement, it was observed that ACF enhanced the size of the single micelle of pluronic L64 from 98 to 168 nm. The size of the cationic mixed micelle with ACF displayed 329 nm and the anionic mixed one showed 291 nm suggesting enhanced entrapment efficiency of their mixed micelle compared to the single micelles. The size was also reconfirmed by SEM analysis. From the conductivity measurements of the two nonionic-ionic micellar systems, the counter ion binding constant β, and the thermodynamic parameters ΔG, ΔH, and ΔS were determined. The negative value of ΔG infers spontaneous binding between ACF and ionic mixed micelles.Article highlightsIonic mixed micelles are more effective than nonionic pair.ACF has more spontaneous binding with anionic mixed micelle compared to cationic.The drug entrapment efficiency is better in mixed micelles than in single micelles.

Surface-Active Ionic Liquid-Assisted Cloud Point Extraction for Pre-Concentration and Determination of Cobalt Ions in Pharmaceutical Preparations.

Herein we describe an efficient, simple, and precise micelle-mediated microextraction strategy based on the aggregation behavior of surface-active ionic liquids (SAILs) for the preconcentration and determination of cobalt ions in pharmaceutical preparations. Unlike the commonly used hydrophobic ionic liquids in IL-based microextraction methods, a water-soluble surface-active ionic liquid [1-hexadecyl 3-methylimidazolium chloride (C16MeImCl)] was used. A modified cloud point extraction (CPE) procedure based on the C16MeImCl-Triton X-114 mixed micellar system was proposed as an efficient extracting phase. A comparison of the analytical features of the extraction process with and without SAILs revealed the benefits of the proposed method. Advantages such as a wider linear range, lower detection limit, higher reproducibility, and improved extraction efficiency highlighted the proposed method over the conventional CPE method. These attractive specifications are due to the higher extraction efficiencies achieved in the presence of the SAIL and its favorable effects at the phase separation stage. Various parameters affecting the extraction efficiency were optimized by univariate and multivariate (Box-Behnken design) approaches. The calibration curve was obtained in the optimal experimental conditions with a linear range from 0.01 to 5.5 mg L-1 of cobalt ion concentration (R = 0.9992) and a detection limit of about 0.005 mg L-1. The RSD% for 10 replicate determinations of 1.0 mg L-1 Co was 0.9%. The proposed method was successfully applied to determine cobalt ions in vitamin B12 ampoules and tablets.

Encapsulation of Quercetin in a Mixed Nanomicellar System to Enhance its Cytotoxicity against Breast Cancer Cells

AbstractThe therapeutic potential of quercetin‐loaded Pluronic® F‐127 (PF‐127)/Tween 80 mixed nanomicelles as a passive targeted drug delivery system for breast cancer therapy is evaluated. Quercetin‐loaded mixed nanomicelles with different mass ratios of drug/PF‐127/Tween 80 were prepared by thin‐film hydration method. The physical interactions of quercetin with PF‐127 and Tween 80 in an optimal ratio were investigated. The results of in vitro drug release experiments showed that the mixed micellar system exhibits a prolonged and sustained release behavior compared to the solution of free quercetin. The in vitro cytotoxicity studies of quercetin‐loaded mixed nanomicelles on breast cancer cells revealed that the encapsulated drug has a lower half‐maximal inhibitory concentration (IC50) value compared to the free drug.

Interaction of bisdemethoxycurcumin with sodium dodecyl sarcosine + Tween 20/Tween 60 mixed surfactants: Insights from multispectral analysis and solubilization effect

The low aqueous solubility of curcuminoids, including bisdemethoxycurcumin (BDMC), severely limits their applications in the food and pharmaceutical industries. This improvement is expected to be achieved by encapsulating them with mixed surfactant micellar systems. In this study, the interaction of BDMC with sodium dodecyl sarcosine (SDDS) + Tween 20/Tween 60 mixed micelles was studied at the molecular level. The molar ratio of Tween 20/Tween 60 to SDDS in the mixed micelles was optimized using response surface methodology. The binding parameters of BDMC to the mixed micelles were determined by fluorescence and UV–vis absorption spectroscopy. Thermodynamic analysis showed that the hydrophobic interaction was dominant in the binding process. The longer hydrophobic chain of Tween 60 was responsible for the stronger interaction of BDMC with SDDS + Tween 60. The binding site of BDMC in the hydrophobic alkyl chains of the mixed micelles was analyzed by copper ion fluorescence quenching analysis, fluorescence polarization analysis, 1H nuclear magnetic resonance spectroscopy, and time-resolved fluorescence spectroscopy. The solubility of BDMC in the mixed micelles was enhanced and SDDS + Tween 60 had more significant solubilization capacity. Therefore, the mixed micellar systems may provide a feasible solution for the application of BDMC in functional food and medicine fields.

Binary micellar schemes of cationic gemini and conventional surfactants: chain length effect

Binary micellar schemes have been appropriated to ascertain the effect of chain length on micellization and interfacial properties. Mixed micellar systems of cationic gemini surfactant, bis-N,N-tetradecyldimethyl-m-phenylenediammonium dibromide (14-m-ɸ-14), and conventional cationic surfactants, viz., dodecyltrimethylammonium bromide (C12TAB), tetradecyltrimethylammonium bromide (C14TAB) and hexadecyltrimethylammonium bromide (C16TAB), in aqueous media were investigated by conductometric, tensiometric, fluorimetric and dynamic light scattering (DLS) techniques at 25 °C. The behavior of the binary mixtures under regular solution theory have been explained in light of Clint’s and Rubingh’s models. A non-ideal behavior was indicated. This was further confirmed by interaction parameter (β) values and activity coefficients. The synergism, an attractive interaction, between the surfactant molecules was ascertained. The average aggregation number () was evaluated by steady-state fluorescence quenching method. The increased with increase in mole fraction of CnTAB (n = 12, 14, 16). The size of the aggregates varied with length of conventional surfactants as exhibited by DLS. The zeta potential values of the mixed micelles increase with increase in mole fractions of CnTAB.

Contrasting impacts of mixed nonionic surfactant micelles on plant growth in the delivery of fungicide and herbicide

HypothesisNonionic alkyl ethoxylate surfactants are widely used in agrochemicals to facilitate the permeation of systemic herbicides and fungicides across the plant waxy film. Industrial grade surfactants are often highly mixed and how the mixing affects their interactions with pesticides and wax films remains largely unexplored. A better understanding could enable design of mixed nonionic surfactants for herbicides and fungicides to maximize their efficiency and reduce wastage whilst controlling their impact on plant wax films. ExperimentIn this study, nonionic surfactants with general structure n-oxyethylene glycol monododecyl ether (C12En) were used to form surfactant mixtures with the same average ethoxylate numbers but different hydrophilic-lipophilic balance (HLB) values. Their mixed micellar systems were then used to solubilize a herbicide diuron (DN) and a fungicide cyprodinil (CP), followed by plant wax solubilization upon contact with wax films. These processes were monitored by 1H NMR and SANS. FindingPesticide solubilization made surfactant micelles effectively more hydrophobic but subsequent wax dissolution caused pesticide release and the restoration of the micellar amphiphilicity. Nonionic surfactants with lower HLBs form larger nanoaggregates, show enhanced wettability, and have better ability to solubilize and permeate pesticides across the wax film, but may cause significant damage to plant growth. These observations help explain why herbicides applied on weeds would benefit from surfactants with lower HLB values while fungicides require surfactants with HLBs to balance between delivery efficiency and potential phytotoxicity risks.

A novel method based on saponification coupled to micelle-extraction for recovering valuable bioactive compounds from soybean oil deodorizer distillate

The feasibility of using saponification coupled to extraction with mixed micellar systems to recover bioactive compounds from soybean oil deodorizer distillate, was evaluated for the first time. Under the selected conditions, saponification with KOH 0.6 M and aqueous micellar system prepared with Tergitol 15-S-7 9% w/w, rhamnolipids 0.25 %w/w and sodium citrate 100 mM pH 5.00, at 65 °C, allow the recovery of almost 100% of α- and δ- tocopherols, and 90% of γ-tocopherols. LC-MS measurements demonstrated that the final extract also contained phytosterols and squalene. Additionally, the obtained extract preserved about 100% of the total antioxidant activity. This result was attributable to the fact that 93% of the tocopherols recovered in the micellar phases resulted to be associated with surfactant micelles, environment that is known to improve their antioxidant capacity. These results open perspectives to the use of this methodology to extract these valuable compounds from complex oily sources.

Influence of an antibiotic drug neomycin sulphate on mixed micellization behavior of imidazolium based surface-active ionic liquids in aqueous media

Imidazolium-based surface-active ionic liquids (SAILs) have unique physicochemical features that make them ideal for biomedical applications. Because SAILs have a higher surface activity than conventional surfactants, they can improve drug permeability across biomembranes, making them superior drug carriers than existing solutions. In-depth studies of interactions prevailing in mixed micellar system of SAILs in the presence of drug are required to fully exploit the promise of these materials in drug delivery applications. Thus, various thermodynamic, mixed micellar and surface-active properties of two imidazolium-based SAILs with different cationic structures i.e.1-dodecyl-3-ethylimidazolium bromide [C12eim][Br] and 1-dodecyl-3-butylimidazolium bromide [C12bim][Br] have been determined in water and 5 mM neomycin sulphate solution in aqueous media. The study has been conducted for different mole fractions of mixed micellar system of SAILs using conductivity and surface tension measurement techniques. Various theoretical models such as Clint, Rubingh, Motomura and Rodenas models have been applied to understand the interactions prevailing in the mixed [C12eim][Br] /[C12bim][Br] system in water and neomycin sulphate solution in aqueous media.

Micellar assembly leading to structural growth/transition in normal and reverse Tetronics® in single and mixed solution environment.

This study scrutinizes the self-association of ethylene oxide (EO)-propylene oxide (PO)-based star-shaped block copolymers as normal Tetronic® (T904) and reverse Tetronic® R (T90R4) with varying molecular characteristics and different hydrophilic-hydrophobic ratios in an aqueous solution environment. These thermo-responsive solutions appear clear, transparent or bluish up to 10%w/v, which anticipated the probable transition of unimers to spherical or ellipsoidal micelles which is complemented by scattering experiments. In a single-solution environment, 10%w/v T904 formed star-shaped micelles at ambient temperature and exhibited a micellar growth/transition with temperature ageing. While 10%w/v T90R4 exists as unimers or a Gaussian coil over a wide range of temperature. Very interestingly, close to the cloud point (CP) flower-shaped spherical and ellipsoidal micelles were formed. A similar proposed micellar scheme was also examined for mixed systems T904 : T90R4 in varying ratios (1 : 0, 3 : 1, 1 : 1, 1 : 3 and 0 : 1) giving an account to the solution behavior of the mixtures. An amalgamation of dynamic light scattering (DLS) and small-angle neutron scattering (SANS) techniques achieved the thorough extraction of the structural parameters of the micellar system. The hydrodynamic diameter (Dh) of the micelles with temperature variation was evaluated from dynamic light scattering (DLS) while the structure factor of the micelles was found by employing small-angle neutron scattering (SANS). Furthermore, the single and mixed micellar systems were quantitatively and qualitatively examined for anticancer drug solubilization using UV-vis spectroscopy for their superior use as potential nanocargos.

Transition from antagonistic to synergistic interaction in mixed micellar system by increase in alkyl chain length of alkyl trimethylammonium bromide

Herein, the electrical conductivity technique used to measure the critical micelle concentration (cmc) for pure cationic surfactants (Dodecyl/cetyltrimethylammonium bromides) and phenothiazine drug (Promethazine hydrochloride), as well as their different mole fractions in 10−3 ​mol/kg 1-methyl-3-octylimidazolium chloride (C8mim.Cl) at different temperatures. By using the cmc values the regular solution theory used to evaluate the micellar mole fraction for DTAB/CTAB-PMT mixed systems. The clint's model used to calculate the ideal critical micelle concentration (cmc∗) that helps to evaluate the ideal micellar mole fraction for studied mixed systems, both explain the deviation from ideality. In addition, interaction parameter βm helps to confirm the nature of interaction (either antagonistic or synergistic) for the studied systems. The calculated parameters confirm a transition in the binding nature from antagonistic to synergistic with the increase in alkyl chain length of cationic surfactant i.e., component of the binary mixed system. The ease of micellization for the studied systems discussed by the standard Gibb's energy of micellization (ΔGm0), as well as the standard enthalpy and standard entropy of micellization were (ΔHm0) and (ΔSm0), respectively to discuss the stability of the studied systems.

Development and optimization of aprepitant/HS15/TW80 composite system: Based on micellization thermodynamics

In this paper, based on the concept of micellization thermodynamics, aprepitant/HS15/TW80 composite system was developed. The interface and micellization behavior of binary and ternary mixtures of Polyoxyl 15 Hydroxystearate (HS15), Polysorbate 80 (TW80) and aprepitant (APPT) have been studied in detail. Surface tension technology was used to study the effects of different HS15/TW80 ratios, temperature, stirring time, pH, and solvents on the thermodynamic behavior of the aprepitant (APPT) mixed micellar system during the preparation process. Air/water interface parameters such as maximum surface excess concentration (Tmax), effectiveness of surface tension reduction (Πcmc), minimum area per surfactant molecule (Amin) and thermodynamic parameters for binary and ternary systems were computed and discussed one by one. The ΔGm and ΔGads values for every studied solution were negative, indicating that micellization, as well as adsorption processes, were spontaneous. Compared with the binary system, the ternary systems were more effective in reducing the critical micelle concentration (CMC) of the solution and promoting the formation of micelles. During the preparation process, when the surfactant ratio in the solution was HS15/TW80 = 1, the temperature was 308.15 K, the stirring time was 4 h, the pH value was 5.00, and the solvent was 0.5% glucose solution, APPT/ HS15/TW80 mixed micellar solution with excellent thermodynamic and physical stability can be obtained. In addition, the results of transmittance and insoluble particles further verified the stability of the composite micelle system. The excellent drug loading characteristics of the new APPT/HS15/TW80 complex micelle system were proved by drug loading experiments. In this study, a stable APPT/HS15/TW80 composite system was established by the theory of micellization thermodynamics.