Sodium N-dodecanoylsarcosinate Research Articles

Impact of 2,2,2-trifluoroethanol (TFE) on hydrophobicity enhancement in the aggregation of sodium N-dodecanoyl sarcosinate (SDDS) with nonionic hydroxyethyl cellulose

An organic solvent has the ability to improve the extent of hydrophobicity in a mixed polymer-surfactant system. The carbohydrate-based polymers, having spacious applications in food and pharmaceutical industries, can interact effectively with anionic surfactants in a hydrophobic fashion. Over the past few decades, such interaction behaviour has been used in surface modification process in the fields of human health care and cosmetics. This article has been highlighted to gain perception about the effect of ‘cosurfactant’ like organic solvent 2,2,2-trifluoroethanol (TFE) on the self-aggregation of anionic surfactant sodium N-dodecanoyl sarcosinate (SDDS), and its interaction with non-ionic biopolymer hydroxyethyl cellulose (HEC). In this work, the interaction behaviour has been detailed by the use of some conventional methods, such as, tensiometry, conductometry, fluorimetry and microcalorimetry in mixed aquo-alcohol solution. Understanding the binding pattern of the HEC-SDDS system, it appears to be dependent on hydrophobic interaction. From tensiometry, TFE exhibits a fair extent of surface activity and thus, it further enhances the hydrophobicity of the medium. An increased alcohol percentage in the water medium has resulted in a significant reduction in the critical micelle concentration (CMC). TFE promotes micellization of the ionic surfactants at a lower concentration by lowering the charge intensity on the polar head groups of the micelles. Thus, the micellization becomes favoured in TFE solvent. The related thermodynamic and surface parameters have been estimated to get an insight into the bulk and interfacial properties of the anionic amphiphile on the polymeric interface in mixed aquo-alcohol solution. The decreasing trend of aggregation number (NAgg) in TFE solvent has been discussed with the aid of steady state fluorescence spectroscopic technique. Dynamic light scattering (DLS) study has been used for the measurement of hydrodynamic size (Dh) and polydispersity index (PDI) of HEC polymer in the presence of varying percentage of TFE. All these observations have been displayed and explored conceptually and in stepwise fashion. Further, HEC-SDDS aggregate has been visualized from field emission scanning electron microscopy (FESEM) imaging. A striking change in the morphology has been seen in the TFE environment. As an additive, TFE is opted because of its unique properties as a solvent and also vast applications in the field of biological and pharmaceutical industry. The system chosen in this study is completely new in the field of surface chemistry and each of the experimental results provided below is distinct. At higher TFE contents, the micellization of SDDS is not feasible.

Detailed physicochemical study and thermodynamic aspects of the interaction between nonionic cellulose derivative hydroxyethyl cellulose and anionic surfactant sodium N-dodecanoyl sarcosinate in aqueous media

BackgroundThe scheme of this work was to study the interaction between hydroxyethyl cellulose (HEC), a non-ionic, water soluble biopolymer and sodium N-dodecanoyl sarcosinate (SDDS), a novel, environmentally friendly amino acid-based anionic surfactant in aqueous medium. The study of this type of interaction is relatively less complicated compared to that between a polymer and a surfactant with opposite charges. MethodsThe critical micelle concentration (CMC) of HEC-induced SDDS has been determined by various physicochemical methods such as tensiometry, conductometry, fluorimetry and microcalorimetry. Several thermodynamic and surface parameters related to the binding of SDDS with HEC have been assessed. The aggregation number (Nagg) of SDDS micelles in the presence of non-ionic HEC polymer has been measured by the steady-state fluorescence method. The hydrodynamic diameter (Dh) and zeta potential (ζ) of the polymer-surfactant aggregate have been measured by the dynamic light scattering method. The interaction study has further been amplified by detecting the change in the surface morphology of the polymer due to surfactant binding using Field Emission Scanning Electron Microscopy (FESEM) and high resolution transmission electron microscopy (HR-TEM) imaging in solvent-free state, as well as visualization of the HEC-SDDS micelle in the solution phase using fluorescence microscopy technique. Significant findingsFrom a physicochemical point of view, hydrophobic synergism seems to be important for understanding the interaction pattern of HEC-SDDS combination. In each scenario, the CMC of SDDS decreases with an increase in weight percentage of HEC. The aggregation number (Nagg) of SDDS micelles is also found to decrease with an increase in weight percentage of HEC in the medium. The hydrodynamic diameter (Dh) and zeta potential (ζ) of the polymer-surfactant aggregate, these two parameters have been found to be strongly dependent on the amphiphile concentration. Finally, investigations of the surface morphologies by taking Field Emission Scanning Electron Microscopy (FESEM), high resolution transmission electron microscopy (HR-TEM) and fluorescence microscopy techniques assist the experimental data.

Spectroscopic and interfacial investigation on the interaction of hemoglobin with conventional and ionic liquid surfactants

A comprehensive investigation on the interactions between equine heart hemoglobin and different surface active agents including ionic liquid surfactants (ILs) was performed in aqueous buffer (pH = 7.4) by ultraviolet-visible and fluorescence spectroscopic techniques coupled with tensiometry. The surface active agents include a cationic surfactant cetyltrimethylammonium bromide (CTAB), two cationic ILs 1-hexadecyl-3-methylimidazolium chloride (C16MeImCl), 1-butyl-3-methylimidazolium octyl sulfate (C4MeImOS), three anionic surfactants sodium N-dodecanoyl sarcosinate (SDDS), sodium dodecylbenzene sulfonate (SDBS), sodium cholate (NaC), and a non-ionic surfactant N-decanoyl-N-methylglucamine (Mega 10). In particular, surfactant-induced conversion of the iron coordination and spin states of hemoglobin was monitored by the shifts of the Soret peak. Fluorescence studies indicated exposure of the tryptophan and tyrosine residues of hemoglobin to polar environment when surface active agents were introduced, the relative contributions of these amino acids to the fluorescence intensity being different for different surfactants. Hemoglobin was found to be unfolded in surfactant solutions. Unfolding of hemoglobin was found to be more pronounced in presence of ionic surfactants than in presence of the non-ionic one.

Physicochemical and conformational studies on interaction of myoglobin with an amino-acid based anionic surfactant, sodium N-dodecanoyl sarcosinate (SDDS)

Physicochemical and conformational studies on the interaction between horse myoglobin, a monomeric water soluble heme protein and sodium N-dodecanoyl sarcosinate (SDDS), an amino-acid based anionic surfactant have been performed at different pHs using surface tension, viscosity, UV–vis and fluorescence spectroscopy, circular dichroism, isothermal titration calorimetry and differential scanning calorimetry. Myoglobin shows surface activity, according to the surface tension measurement. Protein forms aggregates with surfactant molecules and becomes unfolded with increasing SDDS concentration. Again, when concentration of myoglobin increases, the binding ratio decreases; whereas heme changes its spin and coordination number with increasing surfactant concentration. α-Helicity of myoglobin decreases with increase in concentration of surfactant, while β-sheet and random coil appear. The temperature of transition of myoglobin and the enthalpy of thermal denaturation also change at higher concentration of SDDS. The myoglobin-SDDS interaction at different pH, ranging from 5 to 8 has been studied and it shows that pH has very little effect on the conformational change of the myoglobin-SDDS system.

Exploring Physicochemical Interactions of Different Salts with Sodium N-Dodecanoyl Sarcosinate in Aqueous Solution.

Amino acid-based surfactants are used in academics and industry. Sodium N-dodecanoyl sarcosinate (SDDS) is such an amino acid-based surfactant having applications in pharmaceutical, food, and cosmetic formulations. Although the surface properties of this surfactant have been studied in the presence of univalent cationic and anionic salts, there is no report on such solution in the presence of higher valencies. In this experiment, critical micelle concentration (CMC) of SDDS from tensiometry, conductometry, and fluorimetry has been determined. In each case, CMC decreases with increasing salt concentration. Counterion binding of micelles (β), diffusion coefficient (D0), and surface properties, e.g., Gibbs free energy for micellization (ΔGm0), Gibbs surface excess (Γmax), area of exclusion per surfactant monomer (Amin), surface pressure at CMC (πcmc), etc., have been evaluated using methods such as tensiometry, conductometry, and fluorimetry. The hydrodynamic radius of SDDS in the presence of different salts was measured by the light scattering method. Aggregation number and shape of micelle have been determined by small-angle neutron scattering experiment. The nature of amphiphilic packing and the aggregation numbers of the assemblies have also been explored. The results from different experiments have been rationalized and represented systematically.

A study on the interaction of horse heart cytochrome c with some conventional and ionic liquid surfactants probed by ultraviolet-visible and fluorescence spectroscopic techniques

The interactions of a protein cytochrome c with some selected conventional and ionic liquid surfactants have been investigated at pH7.4 using ultraviolet-visible and fluorescence spectroscopic techniques. We used four conventional surfactants - cetyltrimethylammonium bromide (CTAB), dodecyltrimethylammonium bromide (DTAB), sodium N-dodecanoylsarcosinate (SDDS), and N-decanoyl-N-methylglucamine (Mega 10), and a surface active ionic liquid 1-hexadecyl-3-methylimidazolium chloride (C16MeImCl). All the investigated surfactants were found to induce an unfolding of the protein cytochrome c. In presence of CTAB, SDDS and C16MeImCl, the heme iron atom was found to loose methionine from its axial position. Differential binding of the surfactant monomers and their micelles to the protein molecules was inferred. The ionic surfactants were found to be more effective than the nonionic one in unfolding the investigated protein. However, the extent of binding of CTAB/C16MeImCl to cytochrome c reaches a plateau past the critical micellization concentration (cmc) of the surfactant. For each of the cytochrome c-DTAB, cytochrome c-SDDS and cytochrome c-Mega 10 system, although there exists an inflection in the surfactant-binding, saturation point could not be detected. It has been demonstrated from the ultraviolet-visible spectral studies that the oxidation state of iron in cytochrome c does not change when the protein binds with the investigated surfactants.

Binding interaction of sodium-N-dodecanoyl sarcosinate with hemoglobin and myoglobin: Physicochemical and spectroscopic studies with molecular docking analysis

The interaction of an amino acid surfactant, sodium-N-dodecanoyl sarcosinate (SDDS), with two heme proteins, hemoglobin (Hb) and myoglobin (Mb), has been studied employing various physicochemical and spectroscopic techniques like tensiometry, UV–Vis spectroscopy, steady-state fluorometry, time-resolved fluorometry, circular dichroism (CD) spectroscopy, calorimetry and stopped flow kinetics at physiological pH of 7.2 and 298K. Tensiometric and fluorometric analysis suggest that the interaction between SDDS and protein starts with the monomer form of the surfactant which produces small induced micelles. The micelles bind to protein backbone causing denaturation of the protein structure, and finally free micelles are formed on further addition of surfactant. Life-time measurements have been performed to shed light on the binding of surfactant around the tryptophan moieties present in the heme proteins. The changes in protein secondary structure induced by AAS collected from CD measurements reveals that the proteins are quite perturbed upon action of SDDS. The enthalpy change values of each stepwise interaction process have been found from isothermal titration calorimetry (ITC). The kinetics of the protein-surfactant interaction process has been studied using stopped flow technique. Quantum mechanical calculations involving density functional theory (DFT) and molecular docking analysis have been performed to highlight the interactive phenomenon between the surfactant and heme proteins. Thus the entire study shows a total inspection of an amino acid surfactant–heme protein interaction.

Mixed Micelle System Produced by Interaction Between Transglycosylated Stevia and an Ionic Surfactant Improves Dissolution Profile of Mefenamic Acid

Transglycosylated stevia (stevia-G) can effectively improve the dissolution and bioavailability of poorly water-soluble drugs. Furthermore, addition of an ionic surfactant to stevia-G solution has been shown to enhance the dissolution effect of stevia-G on flurbiprofen. Herein, 4 surfactants, namely sodium dodecyl sulfate, sodium N-dodecanoylsarcosinate, sodium monododecyl phosphate, and lauryltrimethylammonium chloride (LTAC) were screened to investigate their synergistic effect with stevia-G in enhancing the solubility of mefenamic acid (MFA). The ternary formulation containing LTAC produced the highest increase in solubility, whereas the binary MFA/LTAC formulation did not increase the solubility of MFA. Surface tension was evaluated to analyze the interaction between stevia-G and each ionic surfactant, wherein the Rubingh model was applied to predict mixed micelle formation between stevia-G and LTAC. Interaction parameters calculated by the Rubingh model reflected mixed micelle formation between stevia-G and LTAC relative to the self-interactions of the 2 individual surfactants. All interaction parameters in this system showed negative values, indicating a favorable interaction (e.g., hydrogen bond or electrostatic and dipole) between binary components in the mixed micelles. Spray-dried particles of ternary formulations (MFA/stevia-G/LTAC) were prepared to evaluate the dissolution profile and physicochemical properties. Dissolution profiling showed that the concentration of MFA released from spray-dried particles was significantly higher than untreated MFA.

Effect of curcumin on the binding of cationic, anionic and nonionic surfactants with myoglobin

Interaction of a globular protein, myoglobin and different surfactants has been studied in the absence and presence of curcumin in phosphate buffer at pH = 7.4 by UV-VIS spectrophotometry, fluorimetry and fluorescence polarization anisotropy methods. Results show that heme environment of myoglobin is changed by cationic cetyltrimethylammonium bromide (CTAB) and sodium N-dodecanoyl sarcosinate (SDDS). In the presence of curcumin, CTAB cannot change the heme; but SDDS can make change. Nonionic surfactant N-decanoyl-N-methylglucamine (Mega 10) cannot change the heme environment. Protein is unfolded by the surfactant. Curcumin can prevent the unfolding of protein in the low concentration region of ionic surfactants such as CTAB and SDDS. In nonionic surfactant media, curcumin accelerates the denaturation process. Due to myoglobin-curcumin complex formation, rotational motion of curcumin decreases in surfactant media and so anisotropy increases.

Interaction of normal and reverse pluronics (L44 and 10R5) and their mixtures with anionic surfactant sodium N-dodecanoylsarcosinate

Interaction of monomeric normal L44 [(PEO)10(PPO)23(PEO)10]) and reverse 10R5 [(PPO)8(PEO)22(PPO)8] pluronics designated as L and R, respectively, and their mixtures with the anionic surfactant sodium N-dodecanoylsarcosinate (SDDS) in aqueous medium has been studied by tensiometry, conductometry, calorimetry and dynamic light scattering methods. The critical aggregation concentration (CAC), concentration of maximum binding (CS), and the extended critical micelle concentration (CMCe) of SDDS resulted from the interaction have been presented. L has shown the formation of CAC, CS and CMCe, whereas R has shown the absence of CAC but the presence of both CS and CMCe. Micellization of SDDS is an endothermic process whereas the formation of CAC and CMCe is exothermic events, the formation of CS is endothermic. The hydrodynamic diameter (Dh) and zeta potential of L and R, and their SDDS interacted species have been determined. Dh decreased with increasing SDDS concentration for L whereas it was invariant for R. Mixed L and R in varied proportions have been also examined in the solution state to probe into their mutual interaction, and interaction with SDDS. The formation of CAC of their mixtures was absent; CMCe formation was exothermic while that of CS was endothermic like their individuals.

Interfacial and aggregation properties of aqueous sodium N-dodecanoylsarcosinate solutions at different pH

The pH dependence of an anionic surfactant, sodium N-dodecanoylsarcosinate (SLAS), has been studied by measuring interfacial tension, fluorescence, dynamic light scattering, etc., in aqueous solutions with phosphate and borate buffers. The interfacial tension (γ) of SLAS decreases remarkably with a pH decrease and is constant at pH > 7.3. The observed values for the critical micelle concentration (cmc) and the surfactant concentration at which its γ value is reduced by 20 mN/m from that of pure water (C20) decrease with a pH decrease, while those also become constant at pH > 6.5 and >7.3, respectively. On the other hand, the interfacial excess of SLAS increases at pH 7.0. These interfacial and micelle properties have been discussed in detail considering the electrostatic interaction and the molecular structures of the hydrophilic headgroup.

Physicochemistry of Interaction between the Cationic Polymer Poly(diallyldimethylammonium chloride) and the Anionic Surfactants Sodium Dodecyl Sulfate, Sodium Dodecylbenzenesulfonate, and Sodium N-Dodecanoylsarcosinate in Water and Isopropyl Alcohol−Water Media

The physicochemistry of interaction of the cationic polymer poly(diallyldimethylammonium chloride) (PDADMAC) with the anionic surfactants sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium N-dodecanoylsarcosinate was studied in detail using tensiometry, turbidimetry, calorimetry, viscometry, dynamic light scattering (DLS), and scanning electron microscopy (SEM). Fair interaction initially formed induced small micelles of the surfactants and later on produced free normal micelles in solution. The interaction process yielded coacervates that initially grew by aggregation in the aqueous medium and disintegrated into smaller species at higher surfactant concentration. The phenomena observed were affected by the presence of isopropyl alcohol (IP) in the medium. The hydrodynamic sizes of the dispersed polymer and its surfactant-interacted species were determined by DLS measurements. The surface morphologies of the solvent-removed PDADMAC and its surfactant-interacted complexes from water and IP-water media were examined by the SEM technique. The morphologies witnessed different patterns depending on the composition and the solvent environment. The head groups of the dodecyl chain containing surfactants made differences in the interaction process.

Interaction of cationic hydroxyethylcellulose (JR400) and cationic hydrophobically modified hydroxyethylcellulose (LM200) with the amino-acid based anionic amphiphile Sodium N-Dodecanoyl Sarcosinate (SDDS) in aqueous medium

Interaction of an ionic amphiphile with an oppositely charged polyelectrolyte may dramatically alter the physicochemistry of the polymer in solution. Exploration of the macro and microscopic details of such processes is a topic of contemporary interest. In this study, results of interaction of the anionic amphiphile, Sodium N-Dodecanoyl Sarcosinate (SDDS) with the cationic hydroxyethylcellulose, JR400 and hydrophobically modified cationic hydroxyethylcellulose, LM400 at the air/water interface and in the bulk over a fair range of concentration in the absence and presence of salt are presented. At a very low concentration, SDDS monomers interact with the polymer; above the critical aggregation concentration (CAC), small micelle like aggregates form complexes with the polymer. The complex, thereafter, self-associates to form a turbid coacervate phase. At increased [SDDS], the turbidity decreases by way of disintegration of the coacervates, and the solution becomes clear. The salt, NaCl affects the SDDS–polymer interaction. The amphiphile interaction with mixed JR400 and LM200 also produces characteristic interfacial and bulk features. Different physical methods are employed to probe the interaction process and an attempt for correlation of the results has been made.

Phase Behavior of N-Acylamino Acid Surfactant and N-Acylamino Acid Oil in Water

In general, spherical or rod micelles in aqueous micellar solution (Wm) or hexagonal liquid crystalline (H1) phases of hydrophilic ionic surfactant change to a bilayer structure of lamellar liquid crystal (Lα) upon addition of amphiphilic oil such as higher alcohol, because such an amphiphilic molecule penetrates in the surfactant palisade layer and the surfactant layer curvature becomes less positive. When an N-acylamino acid derivative oil (N-acylamino acid ester, AAE) such as isopropyl N-dodecanoylsarcosinate (sarcosine N-lauroyl isopropyl, SLIP) is added to sodium dodecyl sulfate (SDS) aqueous solution, a similar phase transition takes place. It was found, however, that the surfactant layer curvature changes in an opposite way from H1 to a discontinuous cubic phase (I1) upon addition of SLIP in the N-acylamino acid based surfactant sodium N-dodecanoylsarcosinate (Sar) instead of SDS. The I1 phase consists of discrete micelles, and its structure is indexed to the Fm3m or F23 space group and confirmed b...

Aqueous Properties of an Anionic Gemini Surfactant with N,N'-Dialkylamide and Carboxylate Groups in Solubilizing System

The aqueous properties of an anionic gemini surfactant, (CH2)2[NCO(C11H23)C2H4CO2Na]2, 212, and 212/sodium dodecanoate(soap) mixtures, were studied in the presence of solubilizate of Orange OT, 1-(o-tolylazo)-2-naphthol. The following parameters were measured:critical micelle concentration(cmc), micelle composition, and solubilization capacity for Orange OT. For the sake of comparison, the properties of SDSa (SDSa=sodium N-dodecanoylsarcosinate, the monomer corresponding to the 212), and mixtures of SDSa/soap, were also investigated. The cmc value of 212 in the solubilizing system obtained, 1.0mM, approximately corresponds to the second cmc value, 1.6mM, obtained in the non-solubilizing system. This second cmc value is much higher than the first cmc value, 0.04mM, determined by the surface tension method. Whereas, the cmc value of SDSa in the solubilizing system is 10.0mM, and close to that, 10.2mM, determined by the surface tension method in the nonsolubilizing system. The solubilization capacity of 212 for Orange OT is 3.0 times that of SDSa. The micelle compositions of the mixtures of 212/soap and SDSa/soap are 2:1 and 1:1, respectively. The solubilization capacity of the 212/soap mixture is 1.8 times that of the SDSa/soap mixture in the region of lower soap molar ratio. The mixed cmc values, 1.9-5mM, of 212/soap mixture in the solubilizing system are markedly lower than those, 12-16mM, in the non-solubilizing system. These behaviors of 212 may reflect the greater tendency of 212 to release Na+ into the bulk phase, permitting larger solubilized amount of Orange OT.

Aqueous Properties of Mixed Anionic Gemini Surfactant and Conventional Anionic Surfactant

In order to determine the characteristics of a mixed system of an anionic gemini surfactant with N, N-dialkylamide and carboxylate groups and a conventional anionic surfactant, aqueous solutions of (CH2)2[NCO(C11H23)C2H4CO2Na]2 (212)/sodium dodecanoate (soap) mixture were studied. The following parameters were measured: critical micelle concentration (cmc), micelle composition, surface tension, foaming power, degree of micelle ionization, and pH values. For the sake of comparison, mixtures of SDSa/soap (SDSa=sodium N-dodecanoylsarcosinate, the corresponding monomer of 212) were also investigated. The cmc values of the SDSa/soap mixture monotonously increase with increasing molar fraction of soap at 30°C. In contrast, the cmc values of the 212/soap mixture are intermediate between those for the pure surfactants over a broad region at 30°C. The composition of 212/soap mixture in micelles is kept at a 2:1 molar ratio in the plateau region. With increase in temperature of 212/soap mixture, cmc values reach a maximum at a soap molar fraction of 0.6. This is obvious at 50°C. The surface tension of 212/soap mixture is minimal at a soap molar fraction of 0.6 at 30°C, at which the surface tension is the lowest among those of the pure surfactants. The foaming power of the 212/soap mixture is maximal at the soap molar fraction of 0.6, at which the foaming power is the largest among those of the pure surfactants. Greater degree of micelle ionization for 212/soap mixture than for SDSa/soap mixture was observed over a broad region. The reason for this is the larger proton uptake by the carboxylate group of 212 than that of SDSa, which releases Na+ into the bulk phase in the mixed micellization process. The evidence for this is the larger increase in pH in the mixed cmc solutions for 212/soap mixture than for SDSa/soap mixture. The unexpected synergistic interaction between 212 and soap molecules is due to stronger reduction of the mutual repulsion between the anionic head groups in the 212 molecule in the presence of a soap molecule.

Effects of organic inhibitors on corrosion of zinc in an aerated 0.5 M NaCl solution

The effects of organic inhibitors on corrosion of zinc in an aerated 0.5 M NaCl solution were investigated by polarization measurements. The inhibitors were sodium benzoate (NaBz), sodium N-dodecanoylsarcosinate (NaDS), sodium S-octyl-3-thiopropionate (NaOTP), 8-quinolinol (8-QOH) and 1,2,3-benzotriazole (BTAH). These inhibitors formed precipitate films of Zn(II) salts or complexes on the zinc surface together with zinc hydroxide and oxide to prevent corrosion in the solution. High inhibition efficiencies of NaOTP were acquired at concentrations c=1×10 −6–3×10 −5 M, BTAH at c=1×10 −4–1×10 −3 M, 8-QOH at c=1×10 −3–3×10 −3 M and NaBz at c=3×10 −3–1×10 −2 M. Films formed on the zinc surface were analyzed by X-ray photoelectron and Fourier transform infrared reflection spectroscopies.