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Abstract In the growing landscape of interest in natural surfactants, selecting the appropriate one for specific applications remains challenging. The extensive, yet often unsystematized, knowledge of microbial surfactants, predominantly represented by rhamnolipids (RLs), typically does not translate beyond the conditions presented in scientific publications. This limitation stems from the numerous variables and their interdependencies that characterize microbial surfactant production. We hypothesized that a computational recipe for biosynthesizing RLs with targeted applicational properties could be developed from existing literature and experimental data. We amassed literature data on RL biosynthesis and micellar solubilization and augmented it with our experimental results on the solubilization of triglycerides (TGs), a topic underrepresented in current literature. Utilizing this data, we constructed mathematical models that can predict RL characteristics and solubilization efficiency, represented as logPRL = f(carbon and nitrogen source, parameters of biosynthesis) and logMSR = f(solubilizate, rhamnolipid (e.g. logPRL), parameters of solubilization), respectively. The models, characterized by robust R2 values of respectively 0.581–0.997 and 0.804, enabled the ranking of descriptors based on their significance and impact—positive or negative—on the predicted values. These models have been translated into ready-to-use calculators, tools designed to streamline the selection process for identifying a biosurfactant optimally suited for intended applications.

In the growing landscape of interest in natural surfactants, selecting the appropriate one for specific applications remains challenging. The extensive, yet often unsystematized, knowledge of microbial surfactants, predominantly represented by rhamnolipids (RLs), typically does not translate beyond the conditions presented in scientific publications. This limitation stems from the numerous variables and their interdependencies that characterize microbial surfactant production. We hypothesized that a computational recipe for biosynthesizing RLs with targeted applicational properties could be developed from existing literature and experimental data. We amassed literature data on RL biosynthesis and micellar solubilization and augmented it with our experimental results on the solubilization of triglycerides (TGs), a topic underrepresented in current literature. Utilizing this data, we constructed mathematical models that can predict RL characteristics and solubilization efficiency, represented as logPRL = f(carbon and nitrogen source, parameters of biosynthesis) and logMSR = f(solubilizate, rhamnolipid (e.g. logPRL), parameters of solubilization), respectively. The models, characterized by robust R2 values of respectively 0.581–0.997 and 0.804, enabled the ranking of descriptors based on their significance and impact—positive or negative—on the predicted values. These models have been translated into ready-to-use calculators, tools designed to streamline the selection process for identifying a biosurfactant optimally suited for intended applications. [ABSTRACT FROM AUTHOR]

High solubility of active materials is crucial for achieving a high‐energy‐density catholyte/anolyte in redox flow batteries. However, solubility largely depends on the compatibility with electrolyte, limiting the types of redox‐active materials that can be used in aqueous electrolytes. Herein, a universal strategy is introduced to attain a high solubility of active materials regardless of the compatibility with aqueous electrolytes while preserving their intrinsic redox activity via micellar solubilization. Leveraging the amphiphilic nature of surfactant molecules, insoluble redox‐active materials are encapsulated by surfactants to be dissolvable with significant solubility. As a demonstration, it is showed that an order‐of‐magnitude solubility enhancement can be achieved for (2,2,6,6‐tetramethylpiperidin‐1‐yl)oxyl (TEMPO) in aqueous catholyte (≈0.8 m). Consequently, the catholyte performance of TEMPO is fully harnessed, leading to an energy density enhancement of more than ten times compared to that in bare electrolyte. It is also observed that micellar solubilization unexpectedly improves the cycle stability, attributed to the mitigation of intermolecular side reactions and reduced crossover. Finally, the fundamental electrochemical reaction mechanism of micelle‐encapsulated TEMPO is discussed. This strategy offers a new insight regarding the solubility and stability of the catholyte/anolyte, and is expected to be applicable to other redox‐active molecules, opening up an unexplored micellar chemistry in redox flow batteries. [ABSTRACT FROM AUTHOR]

The poor aqueous solubility is a well-recognized restriction for the clinical application of many drug molecules. Micelles delivery system provides a promising strategy for the solubility enhancement of hydrophobic drugs. This study developed and evaluated different polymeric mixed micelles prepared using hot-melt extrusion coupled hydration method to improve the solubility and extend the release of the model drug ibuprofen (IBP). The physicochemical properties of the prepared formulations were characterized in terms of particle size, polydispersity index, zeta potential, surface morphology, crystallinity, encapsulation efficiency, drug content, in vitro drug release, dilution stability, and storage stability. Soluplus®/poloxamer 407, Soluplus®/poloxamer 188, and Soluplus®/TPGS mixed micelles had average particle sizes of 86.2 ± 2.8, 89.6 ± 4.2, and 102.5 ± 3.13 nm, respectively with adequate encapsulation efficiencies of 80% to 92%. Differential scanning calorimetry studies confirmed that the IBP molecules were dissolved in the polymers in an amorphous state. The in vitro release results revealed that the IBP-loaded mixed micelles presented extended-release behavior compared to the free drug. In addition, the developed polymeric mixed micelles remained stable upon dilution and one-month storage. These results demonstrated that the hot-melt extrusion coupling hydration method could be a promising, effective, and environment-friendly manufacturing technique for the scale-up production of polymeric mixed micelles to deliver insoluble drugs. [Display omitted] [ABSTRACT FROM AUTHOR]

A natural plant-based surfactant, saponin, was investigated for organic compound and heavy metal pollutant removal via Micellar Enhanced Ultrafiltration (MEUF) to guarantee more sustainable process. Aniline and phenol were used as the model of organic pollutant, methylene blue was selected as reactive dye pollutant, while, Zn and Cu represented heavy metal pollutant. The MEUF process using saponin was successfully removed the pollutant from the model waste water. The highest rejection of 70.76%, 81.65%, 99.95%, 99.05%, and 92.12% was achieved at the addition of 2 times CMC of saponins for removal of phenol, aniline, MB, Zn(II) ion and Cu(II) ion, respectively.

Solubilization of diphenyl diselenide (DPDS) was studied in CTAB, OPE-10 and SDS surfactant solutions at 298 K. Solubility of DPDS increases with increase in the surfactant concentration due to its solubilization in micelles. UV-Vis, H1 NMR and FT-IR spectroscopy was used to study the interaction, location of diphenyl diselenide in the micelle. The change in free energy for solubilization of DPDS in micellar media confirmed the favorable solubilizations in SDS, OPE-10 and CTAB solutions. The DPDS solubility was higher in OPE-10 and CTAB compared to SDS surfactant aqueous solutions. [ABSTRACT FROM AUTHOR]

Although non‐aqueous phase liquids (NAPLs) are typically released to the environment as complex mixtures, most investigations of subsurface remediation focus on single contaminants and ignore the potential effects of co‐constituents on mass recovery and groundwater plume evolution. In this study, we investigate the dissolution and micellar solubilization of binary NAPL mixtures in completely mixed batch reactors and heterogeneous aquifer cells using a commercially‐available nonionic surfactant, Tween® 80. Micellar solubilization of trichloroethene (TCE), tetrachloroethene (PCE), decane, and dodecane measured in batch studies containing binary mixtures of TCE/PCE or decane/dodecane exhibited nonideal behavior that could not be predicted using Raoult's law. For a mixed PCE/decane NAPL, micellar solubilization of PCE was approximately 40% less than predicted, while decane was over 100% greater, which was attributed to expansion of the micelle core. In two aquifer cells containing different size fractions of quartz sand and low‐permeability lenses, the initial NAPL (1:1 TCE:PCE) saturation distributions resulted in "pool" fractions (PFs) of 0.88 and 0.36. During the initial water flood, the greater aqueous solubility of TCE relative to PCE resulted in preferential removal of TCE from the source zone. However, when a 4% (wt) solution of Tween® 80 was introduced, preferential micellar solubilization of PCE relative to TCE resulted in enhanced removal of PCE, with TCE mass discharge reduced from 97% and 90% and PCE mass discharge reduced from 79% and 53%. The observed relationships between mass discharge and mass removal indicating that plume evolution is strongly influenced by the initial NAPL saturation distribution, changes in the mole fraction of NAPL constituents, and regions of high NAPL saturation that persist over time. [ABSTRACT FROM AUTHOR]

Electrospraying (ES) technology is considered an efficient micro/nanoparticle fabrication technique with controlled dimensions and diverse morphology. Gelurice® 48/16 (GLR) has been employed to stabilize the aqueous dispersion of Celecoxib (CXB) for enhancing its solubility and oral bioavailability. Our formula is composed of CXB loaded in polyvinylpyllodine (PVP) stabilized with GLR to formulate microparticles (MPs) (CXB-GLR-PVP MPs). CXB-GLR-PVP MPs display excellent in vitro properties regarding particle size (548 ± 10.23 nm), zeta potential (−20.21 ± 2.45 mV), and drug loading (DL, 1.98 ± 0.059 mg per 10 mg MPs). CXB-GLR-PVP MPs showed a significant (p < 0.05) higher % cumulative release after ten minutes (50.31 ± 4.36) compared to free CXB (10.63 ± 2.89). CXB exhibited good dispersibility, proved by X-ray diffractometry (XRD), adequate compatibility of all components, confirmed by Fourier-Transform Infrared Spectroscopy (FTIR), and spherical geometry as revealed in scanning electron microscopy (SEM). Concerning our anti-inflammatory study, there was a significant decrease in the scores of the inflammatory markers' immunostaining in the CXB-GLR-PVP MPs treated group. Also, the amounts of the oxidative stress biomarkers, as well as mRNA expression of interleukins (IL-1β and IL-6), considerably declined (p < 0.05) in CXB-GLR-PVP MPs treated group alongside an enhancement in the histological features was revealed. CXB-GLR-PVP MPs is an up-and-coming delivery system that could be elucidated in future clinical investigations. [ABSTRACT FROM AUTHOR]

Abstract Poorly water-soluble drugs, such as the antifungal drug griseofulvin (GF), exhibit limited bioavailability, despite their high membrane permeability. Several technological approaches have been proposed to enhance the water solubility and bioavailability of GF, including micellar solubilization. Poloxamers are amphiphilic block copolymers that increase drug solubility by forming micelles and supra-micellar structures via molecular self-association. In this regard, the aim of this study was to evaluate the water solubility increment of GF by poloxamer 407 (P407) and its effect on the antifungal activity against three Trichophyton mentagrophytes and two T. rubrum isolates. The GF water solubility profile with P407 revealed a non-linear behavior, well-fitted by the sigmoid model of Morgan-Mercer-Flodin. The polymer promoted an 8-fold increase in GF water solubility. Fourier-transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), and 2D nuclear magnetic resonance (NMR Roesy) spectroscopy suggested a GF-P407 interaction, which occurs in the GF cyclohexene ring. These results were supported by an increase in the water solubility of the GF impurities with the same molecular structure. The MIC values recorded for GF ranged from 0.0028 to 0.0172 mM, except for T. Mentagrophytes TME34. Notably, the micellar solubilization of GF did not increase its antifungal activity, which could be related to the high binding constant between GF and P407.

[Display omitted] Nonionic 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. In this study, nonionic surfactants with general structure n -oxyethylene glycol monododecyl ether (C 12 E n) 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. Pesticide 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. [ABSTRACT FROM AUTHOR]

The environmental impacts caused by dyes in industrial wastewater are incalculable, due to their adverse effects on the ecosystem and human life, especially when discarded at illegal levels. The ionic micellar flocculation process to remove metals and organic compounds has proven to be an innovative and efficient alternative in the removal of pollutants from aqueous solutions. In this respect, an anionic surfactant, composed of a mixture of surfactants derived from coconut oil and animal fat, was used to remove the ionic dyes methylene blue (MB) and Acid Red 57 (AR57) from an aqueous medium. During extraction trials, the use of a soap base anionic surfactant at concentrations below the critical micelle concentration (CMC) promotes the formation of an insoluble surfactant (cationic dye-anionic monomer), acting as an ionic flocculant by monomers. On the other hand, at concentrations above the CMC, adding calcium ions to an aqueous solution allowed the formation of micellar flocs capable of removing dye, reaching maximum extraction percentages of 60% of MB and 90% of AR57. The influence of initial dye concentration, surfactant concentration, pH and the presence of electrolytes demonstrated that the interaction mechanisms between the dyes and micelles are based on electrostatic interactions and/or micellar solubilization, confirmed by determining the diameter of micellar aggregates. Solvent-assisted ionic micellar flocculation was applied to increase MB removal efficiency from 26 to 91%. [ABSTRACT FROM AUTHOR]

[Display omitted] • Potentiometric method for TAN determination free of chloride salt interference. • Micellar solubilization of acidic compounds of crude oil in O/W nanoemulsions. • The potentiometric method was applied to different types of crude oil samples. • Ca, Mg, and Sr salts in crude oil did not affect TAN determination. The determination of the total acid number (TAN) of crude oils is of great importance in the petroleum refining industry for evaluating the corrosion potentials of oils. The presence of salts CaCl 2 and MgCl 2 at concentrations higher than 100 mg kg−1 in crude oil can interfere with some standard methods used to measure the TAN; thus, CaCl 2 and MgCl 2 salts can hinder the accuracy of TAN determination. In this work, a new method based on the potentiometric titration of O/W nanoemulsions (NMS_TAN) was developed to eliminate the interference of CaCl 2 and MgCl 2 on TAN determination. This method is based on the potentiometric titration of oil-in-water (O/W) nanoemulsions formed via the micellar solubilization of the acidic compounds of crude oil with KOH in propan-2-ol. The O/W nanoemulsion was prepared using ultrasound and a nonionic surfactant (Tween 80). The accuracy of the method was evaluated by recovery tests, and the interferences of the mixture of salts NaCl, CaCl 2 , MgCl 2 , and SrCl 2 in the determination of TAN using NMS_TAN were investigated. NMS_TAN was employed to determine the TAN of 15 oil samples (American Petroleum Institute gravity: 13.2–38.3), and the results were statistically compared with those of standard methods. The accuracy of the NMS_TAN method was not affected by the presence of salts in the crude oil samples. Recoveries from a sample spiked with hexanoic acid ranged from 95.0 % to 100.3 % of the theoretical values. The TAN of crude oil samples with CaCl 2 and MgCl 2 concentrations below 50 mg kg−1 determined using the potentiometric method were comparable to those determined by standard methods. The TAN of crude oil samples with high salt concentrations (>500 mg kg−1) obtained by the standard methods were 77 %–90 % higher than those determined by NMS_TAN. The potentiometric method is fast, simple, and accurate and allows for robust quantifications of the TAN of different crude oil samples without chloride salt interferences. [ABSTRACT FROM AUTHOR]

Electrospraying (ES) technology is considered an efficient micro/nanoparticle fabrication technique with controlled dimensions and diverse morphology. Gelurice® 48/16 (GLR) has been employed to stabilize the aqueous dispersion of Celecoxib (CXB) for enhancing its solubility and oral bioavailability. Our formula is composed of CXB loaded in polyvinylpyllodine (PVP) stabilized with GLR to formulate microparticles (MPs) (CXB-GLR-PVP MPs). CXB-GLR-PVP MPs display excellent in vitro properties regarding particle size (548 ± 10.23 nm), zeta potential (−20.21 ± 2.45 mV), and drug loading (DL, 1.98 ± 0.059 mg per 10 mg MPs). CXB-GLR-PVP MPs showed a significant (p < 0.05) higher % cumulative release after ten minutes (50.31 ± 4.36) compared to free CXB (10.63 ± 2.89). CXB exhibited good dispersibility, proved by X-ray diffractometry (XRD), adequate compatibility of all components, confirmed by Fourier-Transform Infrared Spectroscopy (FTIR), and spherical geometry as revealed in scanning electron microscopy (SEM). Concerning our anti-inflammatory study, there was a significant decrease in the scores of the inflammatory markers’ immunostaining in the CXB-GLR-PVP MPs treated group. Also, the amounts of the oxidative stress biomarkers, as well as mRNA expression of interleukins (IL-1β and IL-6), considerably declined (p < 0.05) in CXB-GLR-PVP MPs treated group alongside an enhancement in the histological features was revealed. CXB-GLR-PVP MPs is an up-and-coming delivery system that could be elucidated in future clinical investigations.

Solubilization of core-shell magnetic nanoparticles has gained new popularity as a versatile partitioning method with the recent growth in nanotechnology and related biotechnology applications. In this sense, Fe3O4/Sio2/Cu nanoparticles (NPs) were designed and characterized by various techniques such as Ultra-violet visible (UV-vis), Fourier transforms infrared (FTIR), X-ray diffractometry (XRD), scanning and transmission electron microscopy (SEM & TEM), energy dispersive X-ray (EDX) and thermogravimetric (TGA) analyses. The size determined by TEM analysis of Fe3O4/Sio2/Cu NPs was found in the range of 24 nm. The diffractometer results verified the impurity-free synthesis of the desired nanoparticles. Micellar solubilization and thermodynamics of micellization were determined correspondingly using a UV-Vis spectrophotometer and conductometer. The thermodynamics of micellization in terms of enthalpy, entropy and standard Gibb's free energy was determined using electrical conductometry. The solubilization parameters viz. partition constant (Kc), binding constant (Kb), partition coefficient (Kx), and the corresponding Gibb's free energies were estimated from the absorption spectroscopic analysis. The experimental outcomes and their computation revealed the rise in the critical micelle concentration of CTAB due to the incorporation of the nanoparticles with the micelles. Moreover, the photo-antibacterial activity of the nanoparticles in the bacteria culture environment showed effectiveness in comparison to the control group. [ABSTRACT FROM AUTHOR]

Surfactant flooding plays a critical role in chemically enhanced oil recovery over the last half century, with the widely accepted mechanism of ultralow interfacial tension (IFT) by forming middle‐phase microemulsions with high concentration of a lead surfactant and a cosurfactant. However, it is found practically from field trials that high oil recovery efficiency can be obtained from low concentration surfactant flooding without forming microemulsions, and the principle behind has not been clearly unraveled yet. Here the solubilization of paraffin oil by the micelles formed with a commercial enhanced oil recovery surfactant, raw naphthenic arylsulfonates (NAS), was investigated using ultraviolet‐visible (UV–Vis) spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM). It is found that paraffin oil can be well solubilized inside the NAS micelles, and mainly localized in the hydrophobic core of the micelles. The solubilization capacity of NAS micelles increases with increasing its concentration, and the size of micelles increases, but morphology of the micelles remains spherical with increasing the amount of paraffin oil, along with an appearance transition from transparent to opaque until the maximum solubilization capacity is reached. Core flooding results with crude oil indicate that in the presence of 0.24 wt.% polymer, addition of 0.1, 0.2, 0.5, and 1.0 wt.% NAS can get oil recovery factor of 24.1%, 27.0%, 30.5%, and 38.3%, which increases linearly with increasing NAS concentration though with the interfacial tension values only in the magnitude of 10−2 mN m−1 level. These findings prove preliminarily micellar solubilization can help increasing oil recovery efficiency even without ultralow IFT. [ABSTRACT FROM AUTHOR]

[Display omitted] • GG/HEC had little effect on the solubilization capacity of SDS micelles for methyl benzoate (MB). • Slight MB solubility enhancement in mixed polymer-SDS systems was due to weak interactions between polymer and MB and SDS. • The weak electrostatic repulsion between HEC/GG and SDS hinders the polymer to participate into SDS micelles. • The solubilization of polymers and the solubilization of micelles proceed independently, as in a single system. • Without attractive polymer-surfactant interaction, the solubilization capacity of SDS was not improved. Micellar solubilization is considered as a key factor affecting the recovery efficiency in chemically enhanced oil recovery (cEOR). However, it is poorly understood how polymers in surfactant-polymer (SP) flooding influences the micellar solubilization. Guar gum (GG) and hydroxyethyl cellulose (HEC) are two important and widely used polysaccharide polymers. In this work, the effect of GG and HEC on the solubilization of a crude oil model compound methyl benzoate (MB) in anionic sodium dodecyl sulfate (SDS) micelles and the underlying mechanism were explored at the molecular scale by NMR spectroscopy. GG and HEC slightly increased the MB solubility in SDS micelles but did not change the solubilization capacity. No correlation peak was observed to demonstrate the attractive interaction between polymer and SDS. After examination, there is weak electrostatic repulsion between HEC/GG and SDS, which made the polymer independent from SDS micelles and was unable to participate in the formation of micelles to alter micellar structure and solubilization behavior. Although the solubility of MB was slightly increased, this increase should originate from weak molecular interactions between polymers, surfactants and hydrophobic molecules, including hydrogen bonding, van der Waals forces and hydrophobic interactions, etc. In summary, without strong electrostatic attraction between polymer and surfactant, the solubilization of polymers and the solubilization of micelles proceed independently, resulting in that the solubilization capacity of SDS micelles was not improved. [ABSTRACT FROM AUTHOR]

Glaucoma is a wide-spread eye disease caused by elevated intraocular pressure. Uncontrolled, this pressure may lead to damages to the optic nerve. Prostaglandin analogues, such as latanoprost and travoprost (which are water-insoluble active substances), are the most used class of active pharmaceutical ingredient. To administer them as eye drops, preservatives, such as benzalkonium chloride, are used as solubilizers. The latter is known to cause a local inflammation when used chronically and is not recommended for patients with ocular surface disorders. In this work, we sought to use polysorbate 80 (PS80) as a solubilizing agent simultaneously with sodium hyaluronate (NaHA) as a thickener and cytoprotective agent for the corneal surface. The first part of this study assessed the compatibility of the excipients with the active substance, using physicochemical methods such as spectra fluorescence and differential scanning calorimetry (DSC), as well as the solubilization mechanism of PS80 regarding prostaglandin analogues using nuclear magnetic resonance (NMR). The second part evaluated the stability of a formula candidate, its viscosity upon instillation, and its pharmacokinetic profile in rabbits as compared to the commercially approved medicine Travatan®. The results show that sodium hyaluronate is inert with respect to travoprost, while PS80 successfully solubilizes it, meaning that benzalkonium chloride is no longer required. Moreover, the pharmacokinetic profiles of the rabbits showed that the original formula described in the present study enhanced the ocular bioavailability of the drug, making it a promising product to control intraocular pressure with a potential reduced dosage of travoprost, therefore minimizing its related side effects.

Fluorescence spectroscopy is a critical tool for exploring interaction between micelles and the molecules. In recent years, extensive researches have been made on the effects of the micelles formed by the different types of surfactants, on diverse systems. Micellar solubilization is widely useful in pharmaceutical industry due to formulation of sparingly soluble drugs in soluble form. This research paper aims to provide unusal approach for the analytical and medical applications of Salicylic acid based on its solubilization in micellar media. Micellar solubilization of Salicylic acids in nonionic, anionic and cationic surfactants is monitored by fluorescence techniques. Absorption spectra was taken by UV-VIS spectrophotometer. The calculated empirical fluorescence coefficient (kf) values are in good agreement with the fluorescence intensity. In conclusion the process of solubilization of salicylic acid in micellar medium facilitates the easy drug delivery to the patients. [ABSTRACT FROM AUTHOR]

Three benzimidazole derivatives, 1-(1H-benzimidazol-2-yl)ethanol (HBE), 1H-benzimidazol-2-yl(diphenyl)methanol (BDM) and 1,2-bis(1H-benzimidazol-2-yl)ethane-1,2-diol (BHBED), have been synthesized following the one-pot rapid green protocol. Complexes of benzimidazole derivatives with six 3d transition metals, Cu(II), Mn(II), Zn(II), Fe(II), Co(II), and Ni(II), have been synthesized by free hydrothermal method. The synthesized products have been characterized by FTIR, 1H, and 13C NMR, and mass spectroscopy, and CHN analysis, and 2:1 ligand to metal stoichiometry has been confirmed. The synthesized ligands and metal complexes have been tested for antioxidant potential (DPPH), inhibitory activity including inhibition of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), lipoxygenase (LOX), α-glucosidase. Micellar solubilization of the metal complexes has been studied in sodium dodecyl sulphate (SDS) by UV-Vis spectroscopy and conductivity. The selected complexes of nickel, zinc and cobalt have demonstrated interaction with SDS, and the value of critical micellar concentration increased in all cases. [ABSTRACT FROM AUTHOR]

An important property of micelles in aqueous solution is their ability to increase the solubility of water insoluble compounds. In this work, the solubilization of Sudan I dye was studied in micellar solutions of three surfactants, possessing the same hydrocarbon tail but different hydrophilic head groups, namely sodium dodecylsulphate (SDS), dodecyltrimethylammonium bromide (DTAB), and dodecyl pentaethyleneoxide (C12EO5). From the result of CMC, the CMC of C12EO5 is much lower than DTAB and SDS. The results showed that, irrespective of the surfactant type, the solubility of Sudan I dye increased linearly with increasing surfactant concentration, as a consequence of the association between the dye and the micelles. The solubilization power and values of micelle-water partition coefficient calculated and found that these values are higher for C12EO5 than DTAB and SDS. Solubilization at micellar surface as well as in hydrophobic core of micelles that increase the solubilization of dye in C12EO5 micellar solution and much lower value of CMC are responsible for high solubilization power of it. The enhanced solubility of dye in DTAB micellar solutions than SDS is a resultant of electrostatic interaction between the positively charged surfactant head group and the polar groups present in the dye structure. The anionic surfactant SDS presented the least solubilization power as a result of electrostatic repulsions between the dye and the anionic surfactant head groups. The free energy of solubilization is energetically favorable for C12EO5 than DTAB and SDS. [ABSTRACT FROM AUTHOR]

The objective of this work was to study the effect of the physiologically relevant enzymes pepsin, pancreatin, and the synthetic surfactant sodium lauryl sulfate (SLS) on the surface tension of the dissolution media and the solubility and dissolution of the weakly basic drug carvedilol. Compendial dissolution media and buffer solutions that simulate the gastrointestinal fluid, prepared with and without the addition of SLS, were used in this study. The surface tension of the dissolution media; critical micelle concentration (CMC) of SLS in buffer solutions; and size, polydispersity index, and zeta potential of SLS micelles loading carvedilol were determined. The solubility and dissolution of carvedilol were investigated and compared with those of the corresponding media prepared without the addition of pepsin, pancreatin, and SLS. Results showed that the addition of pepsin, pancreatin, and SLS lowered the surface tension of the dissolution media to 54.8, 55.7, and ~ 30 mN/m, respectively. The solubility of carvedilol was significantly enhanced with pepsin and SLS; however, no significant difference was found with pancreatin. The dissolution rate of carvedilol was fast in simulated gastric fluid with and without pepsin. The dissolution was further enhanced in media with pancreatin and SLS. The dissolution data were corroborated with the molar micellar solubilization (X) of SLS, ranging between 0.02 and 3.09. Understanding the effect of pepsin, pancreatin, and SLS on the surface tension of the dissolution media and the solubility and dissolution of poorly soluble drugs can improve our knowledge of the performance of these drugs in vivo. [ABSTRACT FROM AUTHOR]

• Solubilization of leflunomide by Pluronic F127 was studied in biorelevant media. • Decrease of leflunomide solubilization by Pluronic F127 was observed in FaSSIF. • Influence of various micellar species on the leflunomide solubilization is considered. The aim of the present study is to investigate and compare the solubilizing effect of Pluronic F127 toward leflunomide in biorelevant media FaSSGF and FaSSIF simulating the gastrointestinal fluids and in the standard pharmacopoeia buffers. More pronounced reduction of leflunomide solubilization by Pluronic F127 was observed in FaSSIF. The influence of various micellar species, which are present in the dissolution media under study, on the leflunomide solubilization was considered in detail. Selectivity of leflunomide interactions with primary and secondary micelles of taurocholate was revealed. Formation of the mixed micelles and their interactions with leflunomide molecules were considered. According to the obtained results, it is suggested that binding of taurocholate with the polymeric micelles results in the weakening of solubilization capability of Pluronic F127 to leflunomide in the biorelevant media. [ABSTRACT FROM AUTHOR]

Preformulation studies were carried out to estimate the solubilization capacity of products of catalytic oxyethylation of triglyceride fractions extracted from the pharmacopoeial lard (Adeps suillus, PP XI). There were determined basic viscosity ([η], Mη and hydrodynamic (Ro, Robs., O) values of micellar solutions of oxyethylated derivatives as well as their surface activity - γcmc25. Critical micellar concentration (cmc) was used to calculate the thermopotential for the formation of micelles (ΔGom). Model studies on micellar solubilization of gemfibrozil, loratadine and valsartan from the solid body surface (phase boundary) were performed under equilibrium conditions at the surfactant concentration of cexp >> cmc. The amount of dissolved lipophilic therapeutic agents with qualitative and quantitative involvement of micellar solubilization was determined by spectrophotometry: (UV) method - cΙsΙ (mg/100 mL) as well as by calculating the solubilization indices - nΙsΙ (mol/mol). The research study has identified structures of oxyethylated derivatives of triglyceride fractions which selectively and effectively solubilize gemfibrozil, loratadine and valsartan from the solid surface in the equilibrium system. The obtained results are a technological inspiration to create a model form of the drug (tablet) with continuous dispersion of lipophilic therapeutic agents (gemfibrozil, loratadine and valsartan), obtained on the basis of the liquefied surfactant structure. [ABSTRACT FROM AUTHOR]

The study aims to show the effect of some Hofmeister series anions on the Krafft temperature (TK) and the critical micelle concentration (CMC) of tetradecyltrimethylammonium bromide (TTAB) in aqueous solution. The TK of TTAB decreases in the presence of strong kosmotropes and moderate chaotropes but increases in the presence of strong chaotropes. Strong kosmotropes and moderate chaotropes remain hydrated in the bulk phase of the aqueous solution and promote dispersion of the surfactant. On the other hand, strong chaotropes form contact ion pairs with the cationic part of TTAB and exhibit salting out effects showing an increase in TK. The CMC of TTAB decreases in the presence of all ions irrespective of their chaotropic and kosmotropic nature. This can be ascribed to screening of the micelle surface charge by the added counterions. The standard Gibbs energy ( Δ G m o ) of micellization was found to be negative, indicating spontaneity of the process. Solubilization of a water-insoluble dye, Sudan II in TTAB micelles, was quantified by the molar solubilization ratio (MSR). The MSR value was found to be higher in the presence of NaCl compared to that in pure water indicating that the added NaCl facilitated solubilization of the dye. [ABSTRACT FROM AUTHOR]

Abstract Solubilization of the disease modifying antirheumatic drugs (methotrexate, leflunomide and sulfasalazine) in micelles of amphiphilic triblock copolymer Pluronic F127 was studied in buffers with physiological pH. The solubilization follows the order leflunomide ≫ sulfasalazine > methotrexate. It was found that the size and ionization state of the drug molecules play an important role in the binding with the Pruronic F127 micelles. The higher solubilizing effect of Pluronic F127 on leflunomide can be caused by smaller geometrical dimensions and higher hydrophobicity of this drug. The 1D 1H and 2D ROESY NMR, UV-vis spectroscopy and dynamic light scattering experiments were used to get insight into the interaction between Pluronic F127 micelles and antirheumatic drugs in aqueous solutions. Among the drugs under consideration only leflunomide can be located in the micelle core more deeply. Effect of Pluronic F127 on membrane permeability was also examined using Permeapad™ barrier imitating the membranes of the intestinal epithelium. It was found that solubilizing effect of Pluronic F127 is accompanied by decrease of drug permeability. Highlights • Solubilization of antirheumatic drugs in Pluronic F127 micelles was studied. • The solubilization follows the order leflunomide ≫ sulfasalazine > methotrexate. • Size and ionization state of drugs play an important role in binding to micelles. • Interactions of Pluronic F127 micelles with antirheumatic drugs were studied. • The solubility-permeability interplay was analyzed. [ABSTRACT FROM AUTHOR]

Absorption spectroscopy, conductivity, and surface tension measurements were carried out at 298 K to study the solubilization of poorly soluble drugs sulfamethoxazole (SMX) and trimethoprim (TMP) in Aerosol‐OT (AOT) micellar media. The binding constants of SMX and TMP to AOT micelles were determined by applying the Benesi–Hildebrand equation. A comparison of the binding constants indicates that the binding tendency of TMP with AOT micelles is higher than that of SMX. To better analyze the incorporation of drugs into anionic AOT micellar media, surface tension measurements were performed in the presence of SMX and TMP in aqueous media. The influence of TMP and SMX on the surface properties of AOT was determined using the Gibbs Adsorption Isotherm. Changes in the surface properties of AOT determined by surface tension measurements in the presence of drugs are in good agreement with the binding constants determined spectrophotometrically. Calculated surface parameters indicate higher incorporation of TMP with AOT than that of SMX. Comparison of the aqueous solubility of TMP and SMX with micellar media indicated solubility enhancements for both poorly soluble drugs. A special attempt was made to highlight simultaneous interactions of TMP and SMX with AOT using both surface tension and conductometric measurements that can be used to determine counterion‐binding parameters. [ABSTRACT FROM AUTHOR]

The efficiency of micellar solubilization is dictated inter alia by the properties of the solubilizate, the type of surfactant, and environmental conditions of the process. We, therefore, hypothesized that using the descriptors of the aforementioned features we can predict the solubilization efficiency, expressed as molar solubilization ratio (MSR). In other words, we aimed at creating a model to find the optimal surfactant and environmental conditions in order to solubilize the substance of interest (oil, drug, etc.). We focused specifically on the solubilization in biosurfactant solutions. We collected data from literature covering the last 38 years and supplemented them with our experimental data for different biosurfactant preparations. Evolutionary algorithm (EA) and kernel support vector machines (KSVM) were used to create predictive relationships. The descriptors of biosurfactant (logPBS, measure of purity), solubilizate (logPsol, molecular volume), and descriptors of conditions of the measurement (T and pH) were used for modelling. We have shown that the MSR can be successfully predicted using EAs, with a mean R2val of 0.773 ± 0.052. The parameters influencing the solubilization efficiency were ranked upon their significance. This represents the first attempt in literature to predict the MSR with the MSR calculator delivered as a result of our research.

The microbial resistance to current antibiotics is increasing day by day, which in turn accelerating the development of new effective drugs. Several studies have proved the high antimicrobial potential of the interaction of several organic ligands with a variety of metal ions. In the present study, a conventional method has been adopted in the synthesis of twelve new heteroleptic complexes of cobalt (II), nickel (II), copper (II) and zinc (II) using three aldimines, namely, (HL1 ((E)-2-((4-chloro-2-hydroxybenzylidene)amino)-3,4-dimethyl-5-phenylcyclopent-2-en-1-one), HL2 ((Z)-3-((4-chlorobenzylidene)amino)-4-hydroxy-5-nitrobenzenesulfonic acid) HL3 (2,2′-((1,2-phenylenebis(azaneylylidene))bis(methaneylylidene))diphenol)) as primary ligands, while phenyl glycine was the secondary ligand. The synthesized compounds were characterized by UV-vis, IR and multinuclear (1H and 13C) NMR spectroscopy, elemental analysis, and electrical conductance. The IR study revealed the coordination of the aldimine derivatives with the -OH and N atom of imine moiety. In contrary to this, the phenyl glycine coordinated to the metal ions via oxygen of carboxylate and nitrogen of the amino group. The spectroscopic analysis unveiled the tetrahedral geometry of the synthesized metal (II) complexes, except for ligand HL3 which exhibited octahedral geometry. The synthesized compounds generally showed antibacterial activity for all microbes, except Ni (II) complexes lacking sensitivity. Furthermore, to access the bioavailability, the synthesized complexes were screened for their solubilization in the micellar media of sodium lauryl sulphate. The metal complex–surfactant interaction was revealed by UV-vis spectroscopy and electrical conductivity measurements.

Micellar solubilization is an important concept in the delivery of poorly water-soluble drugs. The rational selection of the type and the amount of surfactant to be incorporated in a formulation require comprehensive solubility studies. These studies are time and material demanding, both of which are scarce, especially during late discovery and early development stages. We hypothesized that, if the solubilization mechanism or molecular interaction is similar, the solubilization capacity ratio (a newly defined parameter) is dictated by micellar structures, independent of drugs. We tested this hypothesis by performing solubility studies using 8 commonly used nonionic surfactants and 17 insoluble compounds with diverse characteristics. The results show a striking constant solubilization capacity ratio among the 8 nonionic surfactants, which allow us to develop predictive solubility models for both single and mixed surfactant systems. The vast majority of the predicted solubility values, using our developed models, fall within 2-fold of the experimentally determined values with high correlation coefficients. As expected, systems involving ionic surfactant sodium dodecyl sulfate, used as a negative control, do not follow this trend. Deviations from the model, observed in this study or envisioned, were discussed. In conclusion, we have established predictive models that are capable of predicting solubility in a wide range of nonionic micellar solutions with only 1 experimental measurement. The application of such a model will significantly reduce resource and greatly enhance drug product development efficiency. [ABSTRACT FROM AUTHOR]

Passive drug loading can be used to effectively identify suitable colloidal lipid carrier systems for poorly water-soluble drugs. This method comprises incubation of preformed carrier systems with drug powder and subsequent determination of the resulting drug load of the carrier particles. Until now, the passive loading mechanism is unknown, which complicates reliable routine use. In this work, the influence of drug characteristics on the course of passive loading was investigated systematically varying drug surface area and drug solubility. Fenofibrate and flufenamic acid were used as model drugs; the carrier system was a trimyristin nanodispersion. Loading progress was analyzed by UV spectroscopy or by a novel method based on differential scanning calorimetry. While increasing drug solubility by micelle incorporation did not speed up passive loading, a large drug surface area and high water solubility were key parameters for fast loading. Since both factors are crucial in drug dissolution as described by the Noyes-Whitney equation, these findings point to a dissolution-diffusion-based passive loading mechanism. Accordingly, passive loading also occurred when drug and carrier particles were separated by a dialysis membrane. Knowledge of the loading mechanism allows optimizing the conditions for future passive loading studies and assessing the limitations of the method. [ABSTRACT FROM AUTHOR]

The disposal of phenol-bearing wastewaters impacts the environment and, consequently, the health of living bodies. This work evaluates the viability of using micellar solubilization followed by ionic flocculation in the removal of phenol from aqueous solutions. Initially, an anionic surfactant, based on vegetable oil and animal fat, was used to promote the solubilization of phenol in the micelles. Then, calcium was added to the solution to promote the formation of flocs with the ability to capture the phenol-rich micelles. At the end of the experiment, the authors investigated the influence of phenol removal considering surfactant, phenol, and electrolytes concentrations; calcium/surfactant ratio; temperature; pH; equilibrium time; and stirring speed. Phenol desorption from the floc surface was evaluated considering process efficiency and kinetics. The removal efficiency reached values close to 60% using: [Phenol] = 100 ppm, [surfactant] = 1300 ppm, 0.5 calcium/surfactant ratio, T  = 35 °C, pH = 9.7. A 90% desorption was observed, indicating that desorption of phenol from the floc surface occurs spontaneously. Phenol desorption kinetics was fitted using the Lagergren's pseudo-first order model (R 2  = 0.98). [ABSTRACT FROM AUTHOR]

The treatment of effluent is a fundamental part of processing of textile materials due to large volumes produced and the presence of toxic dyes in it. Micellar solubilization followed by ionic flocculation of carboxylate anionic surfactants occurs in two stages. Firstly, solubilization of organic matter occurs inside the micelle, secondly, a solution of calcium is added to the system containing the micelles, causing precipitation of the surfactant in the form of flocs, which drag the organic compound on its surface, bringing the organic compound retained on the surface of the floc, then to be removed from the aqueous medium by a physical separation process. This process was used to remove Reactive Blue 14 (RB14) dye from synthetic effluent. Surfactant carboxylate used was produced from animal/vegetable fat. The effect of surfactant concentration, temperature, stirring speed, contact time, pH and electrolyte concentration were evaluated by observing dye removal efficiency. Enthalpy and entropy show that the process is exothermic and with decreasing randomness. The dye removal efficiency reached 86% at the temperature of 30 °C. Thus, it can be affirmed that application of ionic flocculation using anionic surfactant is an efficient technique in the treatment of textile effluent. [ABSTRACT FROM AUTHOR]

The potential of saponin, a biosurfactant, in the micellar enhanced ultrafiltration (MEUF) process was tested systematically for removal of methyl violet from wastewater. For this, the aqueous extract of reetha ( Sapindus mukorossi ) pericarp which contains saponin was used as the biosurfactant. First, the micellar solubilization of methyl violet in saponin micelles was investigated in terms of molar solubilization power ( SP ) of saponin. It was observed that the adsorption of methyl violet on the agglomerates of saponin micelles was mainly responsible for the enhanced solubilization. The Gibbs free energy of solubilization (calculated as −29.63 kJ mol −1 ) suggested that process was feasible and spontaneous. The MEUF experiments were performed in batch as well as continuous mode using saponin biosurfactant, and the effect of operating parameters on permeate flux and solute retention were evaluated. The removal of methyl violet in MEUF process was >99% achieved with 10 kDa polyethersulfone (PES) membrane for feed dye concentration of 250 mg L −1 at studied conditions. Finally, the saponin in permeate was recovered using n-heptane and n-butanol by solvent extraction process. The solvent n -butanol showed better extraction efficiency as compared to n-heptane for saponin extraction. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are toxic, mutagenic and carcinogenic organic compounds that are widely present in the environment. The bioremediation of PAHs is an economical and environmentally friendly remediation technique, but it is limited because PAHs have low water solubility and fewer bioavailable properties. The solubility and bioavailability of PAHs can be increased by using surfactants to reduce surface tension and interfacial tension; this method is called surfactant-enhanced remediation (SER). The SER of PAHs is influenced by many factors such as the type and concentration of surfactants, PAH hydrophobicity, temperature, pH, salinity, dissolved organic matter and microbial community. Furthermore, as mixed micelles have a synergistic effect on PAH solubilisation, selecting the optimum ratio of mixed surfactants leads to effective PAH remediation. Although the use of surfactants inhibits microbial activities in some cases, this could be avoided by choosing an optimum combination of surfactants and a proper microbial community for the targeted PAH(s), resulting in up to 99.99% PAH removal. This article reviews the literature on SER of PAHs, including surfactant types, the synergistic effect of mixed micelles on PAH removal, the impact of surfactants on the PAH biodegradation process, factors affecting the SER process, and the mechanisms of surfactant-enhanced solubilisation of PAHs. [ABSTRACT FROM AUTHOR]

One of the most widely used approaches for improving drug permeation across the stratum corneum barrier of the skin is the use of chemical penetration enhancers, such as surfactants. In this study, two anionic surfactants, named C12-OPK and C18-OPK, were synthesized via condensation of itaconic acid and fatty amines, with C12 and C18 alkyl chains, respectively. Assessment of impacts on HaCaT keratinocyte cell viability was used as indicator of their potential to cause skin irritation 24 h post exposure (Alamar Blue assay). The LC 50 values of C12-OPK and C18-OPK (144 and 85 mg/L, respectively) were lower than LC 50 values of the most used commercial surfactants (e.g. SDS). The effect of different surfactant concentrations (up to ten times the critical micellar concentration, CMC) on hydrocortisone (HC) solubility and permeation through porcine skin was also evaluated. Results showed that drug solubility increased linearly with increasing concentrations of both surfactants, as a consequence of the association between drug and micelles. In vitro permeation results showed that the permeability coefficient increased at surfactant concentrations lower than the CMC. In particular, a higher enhancement effect on drug permeation was obtained with C18-OPK, due to its hydrophobic properties that ensured a more effective HC permeation in comparison to C12-OPK. [ABSTRACT FROM AUTHOR]

Rod-shaped mesoporous silica nanoparticles (RMSN) with built-in gold nanoparticles or thin gold nanowires in the pore channels were in situ synthesized via a one-step procedure. The insertion of a hydrophobic gold precursor into the mesopores of RMSN was reached through a micellar solubilization mechanism and gold nanoparticles were achieved through a thermal reduction. The resulting RMSN and Au-RMSN samples were characterized by using X-ray diffraction, transmission and scanning microscopies (TEM and SEM), X-ray photoelectron spectroscopy (XPS), nitrogen physisorption and solid-state Nuclear Magnetic Resonance (NMR). The interaction of Au precursor (a carbene complex) with the thiol group at the silica surface was identified and found to play a crucial role in the dispersion of the uniform metal nanoparticles at the internal surface of RMSN. Moreover, TEM micrographs revealed the absence of large gold particles outside the mesopore network. The shape of Au nanoparticles and their loading amount in the mesoporous silica could be easily tuned by altering the concentration of gold precursor. [ABSTRACT FROM AUTHOR]

In this work, a micellar system of benzathine penicillin G (BPG) in sodium deoxycholate (NaDC) was developed and evaluated physicochemically. The solubility profile of the drug in water and buffer solutions at various pH was determined, as well as its n-octanol/water partition coefficient. The Critical Micellar Concentration of NaDC and its ability to incorporate BPG were also assessed. The study was carried out at low and high ionic strength which was adjusted by the addition of sodium chloride. The results demonstrated the ability of the micellar system to incorporate BPG, as well as to increase its apparent solubility in water. The enhancement of the solubility of BPG by the presence of NaDC micelles could be analyzed quantitatively within the framework of the pseudo-phase model. Concentration analysis showed that the micellar system could attain up to 90% incorporation of BPG. The incorporated drug is expected to exhibit improved stability, since the antibiotic enclosed in the hydrophobic core of micelles is rather shielded from the aqueous external environment. Keywords: Benzathine Penicillin G; micellar solubilization; micelles; pre-formulation; sodium deoxycholate.

• Interaction of MB with SDS and SDS-TX-114 has been investigated. • Binding constant and partition co-efficient of MB-Micelle systems have been quantified. • Thermodynamic parameters of micellization have been reported. • CMC of the single surfactant system is greater than the MMS. • MB solubilizes more into MMS as compared to a single surfactant system. 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 (K b) and partition coefficient (K x) 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 (ΔGo mic), enthalpy of micellization (ΔHo mic), and entropy of micellization (ΔSo mic) were calculated using data of specific conductance measurements. Effect of concentration of TX-114 on K x and K b 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. [ABSTRACT FROM AUTHOR]

[Display omitted] • Drug solubility in nonionic surfactant-based biorelevant media was modeled by micellar solubilization model. • The effect of buffer components and pH on drug solubility was quantified by pH-dependent solubility model. • The solubility of amorphous drugs was predicted in various dissolution media. Biorelevant solubilities of drugs are important fundamental data in pharmaceutical development. However, there is still no effective theoretical model to quantitatively describe and predict biorelevant solubility. Therefore, a theoretical modeling approach was proposed for predicting biorelevant solubility. Probenecid (PBD) and flurbiprofen (FBU) were chosen as model drugs. A pH-dependent solubility model was developed to accurately capture the influence of pH adjusted by various buffer systems on solubility, and the micellar effect was described by a micellar solubilization model. Based on the combination of the two models, biorelevant solubility was successfully modeled as a function of temperature, pH, surfactant type and concentration. Several predictive applications were proposed, including predicting the solubility of crystalline and amorphous drugs in biorelevant media with different formulations. These findings demonstrated that the developed theoretical approach achieved quantitative prediction of biorelevant solubility, which is expected to provide important theoretical prediction methodology and fundamental data for the development of drugs as well as their formulations. [ABSTRACT FROM AUTHOR]

Three homologues of a novel biodegradable diester-linked cationic gemini surfactant series, C m H 2m+1 (CH 3 ) 2 N + (CH 2 COOCH 2 ) 2 N + (CH 3 ) 2 C m H 2m+1 .2Cl − (m-E2-m; m = 12, 14, 16), were used for investigation of the solubilization of polycyclic aromatic hydrocarbons (PAHs) such as naphthalene, anthracene and pyrene in single as well as binary surfactant solutions. Physicochemical parameters of the pure/mixed systems were derived by conductivity and surface tension measurements. Dissolution capacity of the equimolar binary surfactant solutions towards the PAHs was studied from the molar solubilization ratio ( MSR ), micelle–water partition coefficient (K m ) and free energy of solubilization (Δ G s 0 ) of the solubilizates. Influence of hydrophobic chain length of the dimeric surfactants on solubilization was characterized. Aqueous solubility of the PAHs was enhanced linearly with concentration of the surfactant in all the pure and mixed gemini–gemini surfactant systems. [ABSTRACT FROM AUTHOR]

Self-propelled droplets are a class of active matter systems composed of one fluid dispersed in another immiscible fluid. Despite the inherent spherical symmetry in the initial droplet shape and composition, self-propulsion in these systems is achieved by a spontaneous symmetry-breaking bifurcation. Either a chemical reaction, micelle-induced solubilization, or a phase transition may induce gradients in the interfacial tension, generating a Marangoni convection and thereby resulting in self-propulsion. The simplicity associated with these self-propelled droplet systems makes them excellent candidates for investigating the solitary and collective behaviour of several biological swimmers, ranging from single-celled bacteria to school of fishes. Additionally, due to their tunable mobility characteristics, these swimmers have immense potential as smart materials designed to execute intricate tasks in microscopic domains. In this review, we present state-of-the-art experimental and theoretical research relevant to self-propelled swimming droplets. [Display omitted] [ABSTRACT FROM AUTHOR]

• A micellar solubilization model describes the effect of different surfactants on API solubility. • A pH-dependent solubility model quantifies the effect of buffer components on API solubility. • The proposed modeling strategy models the biorelevant solubility of APIs accurately. • The solubilization ability of CTAB for NAP and IND is greater than that of SDS. • Both surfactants and buffer components highly influenced API solubility. The solubility of active pharmaceutical ingredients (APIs) in biorelevant media is important fundamental data for API formulation design and contributes to better evaluation of in vivo dissolution kinetics. However, these data are mainly determined by experimental measurements, which is rather time and cost consuming. Therefore, it is essential to develop a novel theoretical strategy to describe and predict API solubility in biorelevant media. In this work, the solubilization effect of micelle and the effect of pH as well as ion components on the solubility of naproxen and indomethacin were determined experimentally. A micellar solubilization model and pH-dependent solubility model were proposed to model the effect of various micelles and pH (including buffer components) on API aqueous solubility, respectively. The combination of the two model successfully described the biorelevant solubility of APIs as function of temperature. The proposed strategy could provide insights into the mechanisms of micelle and different pH regulated by different buffer components on API solubility and could accurately describe the solubility of APIs in biorelevant media. This work is expected to provide theoretical guidance for API formulation development. [ABSTRACT FROM AUTHOR]

[Display omitted] • Proposing and implementing micellar solubilization CE and pre-column derivatization CE. • Verified PEG−LDS and PEG−SDS complexes to be pseudo-polyanions by the improved CE. • Nonionic water-soluble polymer−anionic surfactant complexes are unique pseudo-polyanions. • Ratios of bridging-to-diffusion ion and charge-to-size are dominated by bridging ions. • The smaller the hydrated ionic radius is, the stronger the pseudo-polyanion nature is. "Pseudo-polyanions" are formed in some mixtures of nonionic water-soluble polymers and anionic surfactants with ultraviolet (UV) absorption signals, which is verified by capillary electrophoresis (CE) equipped with an UV detector. However, it is still unclear whether two typical mixtures of PEG (polyethylene glycol)−LDS (lithium dodecylsulfate) and PEG−SDS (sodium dodecylsulfate) are pseudo-polyanions or not due to lack of necessary UV absorption. Therefore, with the help of UV probes or UV labeling reagents, micellar solubilization CE and pre-column derivatization CE are implemented to make the mixtures detectable or "visible" by a UV detector. Experimental results show that both PEG–LDS and PEG–SDS complexes are pseudo-polyanions verified by the above strategies. Combined with previous works, most mixtures of nonionic water-soluble polymers and anionic surfactants can form unique pseudo-polyanions by dint of ion bridge no matter whether with or without UV absorption. What's more, the bridging-to-diffusion ion ratio and the charge-to-size ratio of pseudo-polyanions are dominated by the bridging ions, and the smaller the hydrated ionic radius (H+ < K+ < Na+ < Li+) is, the stronger the polyanion nature is. [ABSTRACT FROM AUTHOR]

Based on the sensitive reaction of Co(II) and salicyl fluorone with the presence of cetylpyridinium bromide in basic solution, a new method of flow injection micelle-solubilized spectrophotometry was developed for the determination of cobalt. The reaction was monitored for the absorbance of Co(II) at 540 nm. The reagents, flow injection variables and effects of foreign ions were investigated and the optimum conditions were established. At the optimum test conditions, the developed method provides a linearity range of 3-40 μg L-1 with a detection limit of 0.1 μg L-1 at about 60 h-1 sampling frequency. Relative standard deviation of 0.91, 0.95 and 0.89% were obtained for the determination of 3, 15 and 30 μg L-1 Co(II) solution. The proposed method has been successfully applied for analysis of trace amounts of cobalt in water samples. [ABSTRACT FROM AUTHOR]

Surfactants are routinely included in tablets during wet or dry granulations or along with directly compressible vehicles to improve wetting, disintegration and dissolution. Besides this micellar solubilization can improve permeability of poorly soluble drugs via gastrointestinal tract membranes thereby enhancing oral bioavailability. Microparticle-entrapped micelles (MEM) technology is a novel method of incorporating surfactants in tablets for improving in vitro and in vivo performance of poorly water-soluble drugs. Valsartan (VAL) was solubilized in cremophor EL micelles at cloud point temperature; lactose was dissolved in micellar dispersion and the dispersion was directly spray-dried to obtain solid product, which was subsequently converted into tablets using suitable excipients. VAL tablets produced by applying MEM technology improved dissolution performance of valsartan tablets. These tablets exhibited superior dissolution rate over controls and marketed tablets in all media employed irrespective of pH conditions and composition. [ABSTRACT FROM AUTHOR]