Micelles Of Brij Research Articles

Fluorescence quenching of chloroquine by Cu2+ in micelles

Abstract Fluorescence quenching, very often, has been employed as a suitable technique for characterization of the immediate environment of a fluorophore. This paper reports the absorption and fluorescence characteristics of an antimalarial drug, chloroquine, in presence of the salt copper chloride (CuCl2) in aqueous and micellar systems. Chloroquine fluorescence was quenched considerably by the copper ion (Cu2+); quenching ability of Cu2+ in micellar solution of the cationic surfactant cetyltrimethylammonium chloride (CTAC) is higher than that in water while for the nonionic surfactant polyoxyethylene (20) cetyl ether (Brij 58) it has much lower quenching efficiency. Downward deviations in Stern-Volmer (SV) plots were observed for all the systems. Possibly, the chloroquine molecules are inserted somewhat deeper inside the micelles of Brij 58 as compared to the CTAC micelles and in Brij 58 micelles the fluorophore might be less exposed to the aqueous phase to become available for the metal ion quenching.

Application of non-ionic surfactant as a developed method for the enhancement of two-phase solvent bar microextraction for the simultaneous determination of three phthalate esters from water samples

The extraction of phthalate esters (PEs) from aqueous matrices using two-phase solvent bar microextraction by organic micellar phase was investigated. A short hollow fiber immobilized with reverse micelles of Brij 35 surfactant in 1-octanol was served as the solvent bar for microextraction. Experimental results show that the extraction efficiency were much higher using two-phase solvent bar microextraction based on non-ionic surfactant than conventional two-phase solvent bar microextraction because of a positive effect of surfactant-containing extraction phase in promoting the partition process by non-ionic intermolecular forces such as polar and hydrophobicity interactions. The nature of the extraction solvent, type and concentration of non-ionic surfactant, extraction time, sample pH, temperature, stirring rate and ionic strength were the effecting parameters which optimized to obtain the highest extraction recovery. Analysis of recovered analytes was carried out with high performance liquid chromatography coupled with ultraviolet detection (HPLC–UV). Under the optimum conditions, linearity was observed in the range of 1–800 ng mL−1 for dimethylphthalate (DMP) and 0.5–800 ng mL−1 for diethylphthalate (DEP) and di-n-butyl phthalate (DBP) with correlation determination values above 0.99 for them. The limits of detection and quantification were ranged from 0.012 to 0.03 ng mL−1 and 0.04–0.1 ng mL−1, respectively. The ranges of intra-day and inter-day RSD (n = 3) at 20 ng mL−1 of PEs were 1.8–2.1% and 2.1–2.6%, respectively. Results showed that developed method can be a very powerful, innovative and promising sample preparation technique in PEs analysis from environmental and drinking water samples.

Effect of neutral salts on the excited state proton transfer in the fluorescent probe anchored to the uncharged micelles

Abstract We study the salt effect on the excited state proton transfer (ESPT) in the fluorescent probe of 2-hydroxynaphthalene (dodecylo)-6-sulphonamide (NSDA) anchored on the nonionic Brij35 micelles. The results of spectrofluorimetric, electrophoretic and equilibrium dialysis measurements, allowed us to explain the variations in the ESPT rate constants in the presence of different neutral salts (NaCl, KCl, KSCN, NH 4 SCN) as resulting from anion accumulation at the particle surface. Similarly to electric double layer in the charged micelles, an ionic layer system is also formed around the nonionic micelles. The dimensions of anionic and cationic layers as well as those of the whole ionic envelope around the nonionic particles are estimated. Furthermore, the electric potential generated within the ionic layer system and acting on the proton dissociating from the probe is determined and interpreted. Different impact of Cl − and SCN − ions on photophysical parameters of the targeted system have been explained through a synergy effect between hydrophobicity and polarizability of anions adsorbing on the nonionic micelle surface.Taking into account the existing analogy between micelles and living cells, we can assume that these results will contribute to a better understanding of salt effect in such important biological phenomena as the cell adhesion to surfaces, thermal denaturation of proteins and the aggregation of erythrocytes.

Effect of Surfactants on Hydrolysis of Mono-N-ethyl-o-toluidine Phosphate

AbstractHydrolysis of phosphate ester (Mono-N-ethyl-o-toluidine phosphate) in the presence of different surfactants has been studied at 303 K. The rate of reaction has been found to be first-order and fractional order kinetics with respect to [substrate] and [HCl] respectively. The cationic micelles of cetyltrimethylammonium bromide (CTAB), anionic micelles of sodium dodecyl sulfate (SDS) and nonionic micelles of Brij-35 enhanced the rate of reaction to a maximum value and thereafter, the increase in concentration of surfactant decreased the reaction rate. The rate of reaction increased with increase of dielectric constant of the medium. The variation in the rate of hydrolysis by micelles was treated by considering the Menger-Portnoy, Piszkiewicz's and Berezin kinetic models. The various thermodynamic parameters have also been evaluated. The added salts viz KCl, KNO3, K2SO4 enhanced the rate of reaction in the presence of cationic, anionic and non-ionic micelles. The kinetic parameters i. e. micellar phase (kΨ) and binding constant (KS) were determined from the rate (surfactant) profile.

Effects of polyethoxylate lauryl ether (Brij 35) addition on phenanthrene biodegradation in a soil/water system

Non-ionic surfactants usually are often selected for use in surfactant flushing technology, which is a process that can be used as part of PAH-contaminated soil bioremediation. Phenanthrene (PHE) biodegradation in the presence of polyethoxylate lauryl ether (Brij 35) was studied in two soil/water systems. The natural soil organic matter content (SOM) and the present of Brij 35, both above the critical micelle concentration (CMC) and below the CMC, changed the rate of PHE biodegradation in the presence of Brij 35. PHE biodegradation is different in the two different soil/water systems: PHE > PHE-Brij 35-Micelle > PHE-Brij 35-Monomer in the clay/water system; PHE-Brij 35-Micelle > PHE-Brij 35-Monomer > PHE in the natural soil/water system. Among the free-living species associated with PHE-Brij 35 biodegradation, Brevundimonas diminuta, Caulobacter spp., Mycoplana bullata, Acidovorax spp. and Pseudomonas aeruginosa accounted for 90.72% to 99.90% of the bacteria present. Specific hydrolytic enzymes, including esterases, glycosol-hydrolases and phosphatases, are expressed during PHE biodegradation. The information presented here will help the engineering design of more effective PAH bioremediation systems that use Brij 35 series flushing technology. In particular, micelles of Brij 35 can be used to accelerate the rate of remediation of PAH-contaminated soil in natural soil/water systems.

Citral degradation in micellar structures formed with polyoxyethylene-type surfactants

In a micellar solution, the chemical degradation of poorly water-soluble food flavours can be influenced by the properties of the surfactants forming the micelles in aqueous solutions. To evaluate how hydrophilic head size and hydrophobic tail length influence the chemical degradation rate of food flavour, micelles were prepared with Brij surfactants (Brij 35, 58, 78 and 700), each of which had very similar molecular structures (polyoxyethylene fatty acid ether). The chemical degradation of citral in Brij micelles was found to be highest in an acidic environment. There was no significant difference in the chemical degradation rate of citral in Brij micelles in non-acidic conditions, regardless of the hydrophilic head size or hydrophobic tail length. Brij surfactants with larger hydrophilic heads effectively retarded the chemical degradation of citral in an acidic environment. Our findings suggest that the length of the hydrophobic tail rarely influenced the micelle’s ability to chemically stabilize citral.

Lipid Absorption Triggers Drug Supersaturation at the Intestinal Unstirred Water Layer and Promotes Drug Absorption from Mixed Micelles

To evaluate the potential for the acidic intestinal unstirred water layer (UWL) to induce drug supersaturation and enhance drug absorption from intestinal mixed micelles, via the promotion of fatty acid absorption. Using a single-pass rat jejunal perfusion model, the absorptive-flux of cinnarizine and (3)H-oleic acid from oleic acid-containing intestinal mixed micelles was assessed under normal acidic microclimate conditions and conditions where the acidic microclimate was attenuated via the co-administration of amiloride. As a control, the absorptive-flux of cinnarizine from micelles of Brij® 97 (a non-ionizable, non-absorbable surfactant) was assessed in the absence and presence of amiloride. Cinnarizine solubility was evaluated under conditions of decreasing pH and decreasing micellar lipid content to assess likely changes in solubilization and thermodynamic activity during micellar passage across the UWL. In the presence of amiloride, the absorptive-flux of cinnarizine and (3)H-oleic acid from mixed micelles decreased 6.5-fold and 3.0-fold, respectively. In contrast, the absorptive-flux of cinnarizine from Brij® 97 micelles remained unchanged by amiloride, and was significantly lower than from the long-chain micelles. Cinnarizine solubility in long-chain micelles decreased under conditions where pH and micellar lipid content decreased simultaneously. The acidic microclimate of the intestinal UWL promotes drug absorption from intestinal mixed micelles via the promotion of fatty acid absorption which subsequently stimulates drug supersaturation. The observations suggest that formulations (or food) containing absorbable lipids (or their digestive precursors) may outperform formulations that lack absorbable components since the latter do not benefit from lipid absorption-induced drug supersaturation.

Study of Influence of Salt Additives on Mixed Reverse Micelles via Reverse Microemulsion Chromatography and UV–visible Spectroscopy

Abstract Reverse micellar mobile phases based on poly(oxyethylene) (4) lauryl ether (Brij 30) and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) were used as mobile phases in HPLC. The chromatographic behavior of the model compounds was studied on the basis of reverse micellar mobile phases modified by salt additives. The binding of o-nitroaniline (o-NA) to the micelles of Brij 30 was determined by UV–visible spectroscopy. The different influences of kosmotropic and chaotropic anions on the binding constant Kb was revealed. This may be controlled by the different arrangement of kosmotropic and chaotropic ions in the water core of reverse micelles.

Solubilisation capacity of Brij surfactants

The aim of this study was to investigate the potential of selected Brij non-ionic surfactants for enhancing the solubility of poorly water-soluble drugs. Griseofulvin was selected as a model drug candidate enabling comparisons to be made with the solubilisation capacities of other poly(ethylene oxide)-based copolymers. UV/Vis and (1)H NMR spectroscopies were used to quantify the enhancement of solubility of griseofulvin in 1 wt% aqueous micellar solutions of Brij 78 (C(18)H(37)E(20)), Brij 98 (C(18)H(35)E(20)) and Brij 700 (C(18)H(37)E(100)) (where E represents the OCH(2)CH(2) unit of the poly(ethylene oxide) chain) at 25, 37 and 40 °C. Solubilisation capacities (S(cp) expressed as mg griseofulvin per g Brij) were similar for Brij 78 and 98 (range 6-11 mg g(-1)) but lower for Brij 700 (3-4 mg g(-1)) as would be expected for the surfactant with the higher ethylene oxide content. The drug loading capacity of micelles of Brij 78 was higher than many di- and triblock copolymers with hydrophilic E-blocks specifically designed for enhancement of drug solubility.

Reversible Fluorescence Quenching by Micelle Selective Benzophenone-Induced Interactions between Brij Micelles and Polyacrylic Acids: Implications for Chemical Sensors

The fluorescence response of pyrene has been studied in the presence of nonionic brij micelles and poly(acrylic acid) (PAA) with benzophenone (BP) as a neutral hydrophobic quencher. Pyrene emission is quenched ("off" state) in the presence of BP in brij 35 (polyoxyethylene-23-lauryl ether) and brij 56 (polyoxyethylene-10-cetyl ether) micelles. Quenched pyrene emission is selectively recovered ("on" state) for brij 35 micelles with the addition of PAA (starting conc 2.0 x 10(-5) M). Due to the interaction of PAA and brij 35 micelles and the relatively easier accessibility of PAA polymer chains near the bulky polyoxyethylene chain of brij 35 micelles, the chances of BP partition inside the hydrophobic polymer coil are more compared to brij 56 micelles. The PAA sensing ability of the "brij 35:pyrene:BP" system is dependent on the molecular weight (M) of the polymer. Fluorescence recovery has been observed with PAA (M approximately 150000) and complete recovery has been recorded with high M of PAA (M approximately 450000); however, no fluorescence change is observed in the presence of low M of PAA (M approximately 2000). In solution, such selective reversible fluorescence quenching has the potential for a new class of highly sensitive chemical sensor systems.

Recombinant Expression, in Vitro Refolding, and Biophysical Characterization of the Human Glucagon-like Peptide-1 Receptor

Activation of the glucagon-like peptide-1 receptor (GLP-1R) upon ligand binding leads to the release of insulin from pancreatic cells. This strictly glucose-dependent process renders the receptor and its ligands useful in the treatment of type II diabetes mellitus. To enable a biophysical characterization in vitro, we expressed the human full-length GLP-1R in the cytosol of Escherichia coli as inclusion bodies. After purification, refolding of the SDS-solubilized receptor was achieved by the exchange of SDS against the detergent Brij78 using an artificial chaperone system. Far-UV circular dichroism spectroscopic studies revealed that the receptor adopts a characteristic alpha-helical structure in Brij78 micelles. Ligand binding of the renatured protein was quantified by fluorescence quenching and surface plasmon resonance spectroscopy. In the presence of Brij micelles, the refolded receptor binds the agonist exendin-4 with an apparent dissociation constant of approximately 100 nM in a reversible one-step mechanism. To demonstrate that the detected ligand binding activity is not only due to an autonomously functional N-terminal domain (nGLP-1R) but also due to additional contacts with the juxtamembrane part, we separately expressed and refolded the extracellular domain relying on identical protocols established for the full-length GLP-1R. In support of the suggested multidomain binding mode, the nGLP-1R binds exendin-4 with a lower affinity (K(app) in the micromolar range) and a different kinetic mechanism. The lower ligand affinity of the nGLP-1R results entirely from a decreased kinetic stability of the receptor-ligand complex, dissociation of which is approximately 40-fold faster in the case of the nGLP-1R compared to the full-length GLP-1R. In summary, a framework was developed to produce functional human full-length GLP-1R by recombinant expression in E. coli as a prerequisite for eventual structure determination and a rigorous biophysical characterization including protein variants.

Complexation of Cu(II) by Original Tartaric Acid−Based Ligands in Nonionic Micellar Media: Thermodynamic Study and Applications

The complexation of Cu(II) with original alkylamidotartaric acids (C(x)T) is investigated in homogeneous aqueous medium and in the presence of nonionic micelles of Brij 58 (C16EO20), thanks to various analytical techniques such as NMR self-diffusion experiments, CD and UV-vis spectroscopy, ESI mass spectrometry, pHmetry and micellar-enhanced ultrafiltration (MEUF). First, a complete speciation study proves the formation of dimeric complexes in water and provides their formation constants. Second, a similar study is led in the presence of nonionic micelles. It underlines a modification of the apparent equilibrium constants in micellar medium and demonstrates that the structure of the complexes is slightly modified in the presence of micelles. This thermodynamic and structural study is applied to modelize the evolution of the extraction yields of Cu(II) by the micelles as a function of pH and to identify the complexes extracted in the micelles. The effects of the chain length of the ligand (C3T vs C8T) on the solubilization properties are put into relief and discussed. Anionic species are proved to be more incorporated in the nonionic micelles than the cationic species. The extracting system constituted of octylamidotartaric acid (CsT) solubilized in nonionic micelles of Brij 58 is demonstrated to be very efficient for the extraction of Cu(II) by MEUF, this technique being an interesting green alternative to traditional solvent extraction.

Catalytic effect of alloxazinium and isoalloxazinium salts on oxidation of sulfides with hydrogen peroxide in micellar media

Three novel amphiphilic alloxazinium salts were prepared: 3-dodecyl-5-ethyl-7,8,10-trimethylisoalloxazinium perchlorate (1c), 1-dodecyl-5-ethyl-3-methylalloxazinium perchlorate (2b), and 3-dodecyl-5-ethyl-1-methylalloxazinium perchlorate (2c). Their catalytic activity in thioanisole (3) oxidation with hydrogen peroxide was investigated in micelles of sodium dodecylsulfate (SDS), hexadecyltrimethylammonium nitrate (CTANO3) and Brij 35. Reaction rates were strongly dependent on the catalyst structure, on the type of micelles, and on pH value. Alloxazinium salts 2 were more effective catalysts than isoalloxazinium salts 1. Due to the contribution of micellar catalysis, the vcat/v0 ratio of the catalyzed and non-catalyzed reaction rates was almost 80 with salt 2b solubilized in CTANO3 micelles. Nevertheless, the highest acceleration was observed with non-amphiphilic 5-ethyl-1,3-dimethylalloxazinium perchlorate (2a) in CTANO3 micelles (vcat/v0 = 134). In this case, salt 2a presumably acts as a phase-transfer catalyst bringing hydrogen peroxide from the aqueous phase into the micelle interior. Synthetic applicability of the investigated catalytic systems was verified on semi-preparative scale.

Enhanced Hydrolysis of p-Nitrophenyl Picolinate by Schiff Base Mn(III) Complexes in Gemini 16-6-16 Micelles

Hydrolysis of p-nitrophenyl picolinate (PNPP) catalyzed by three Schiff base Mn(III) complexes (MnL2Cl) were investigated in Gemini 16-6-16 micelle media. , and systems give 835-, 969-, and 1931-fold rate enhancements in the hydrolysis of PNPP under the comparable conditions, respectively. Moreover, Effects of varied micelles on the reactivity of PNPP hydrolysis were especially studied. The results obtained indicate that rates of hydrolysis of PNPP are approximately 1.5- and 4-fold larger in Gemini 16-6-16 micelles than in CTAB micelles and Brij35 micelles, respectively. Effects of ligand structure on the activities of these three complexes are discussed in detail.

Ophthalmic delivery of Cyclosporine A from Brij-97 microemulsion and surfactant-laden p-HEMA hydrogels

Cyclosporine A (CyA) is an immunosuppressant drug that is used for treating a variety of ocular diseases and disorders. CyA is commonly delivered via eye drops, which is highly inefficient due to a low bioavailability of less than 5%. The bioavailability of ophthalmic drugs can be substantially improved to about 50% by delivering them via contact lenses. This paper focuses on the development of nanostructured poly (2-hydroxyethyl methacrylate) (p-HEMA) hydrogels containing microemulsions or micelles of Brij 97 (C 18H 35(OCH 2CH 2) 10) for extended delivery of CyA. Release of CyA from these nanostructured hydrogels was performed in vitro to explore the mechanisms of release and the effects of surfactant concentration, processing conditions and storage on the release kinetics. Results show that the surfactant and microemulsion-laden gels can deliver CyA at therapeutic dosages for a period of about 20 days. Release of the drug is diffusion controlled with effective diffusivities decreasing with increasing surfactant loading. The release kinetics are relatively similar for both surfactant and microemulsion-laden gels with comparable surfactant loading. The results also show that these hydrogels retain their effectiveness even after exposure to all the relevant processing conditions including unreacted monomer extraction, autoclaving and packaging, and so these materials seem to be very promising for ophthalmic delivery of CyA and perhaps other drugs.

Organocatalytic sulfoxidation in micellar systems containing amphiphilic flavinium salts using hydrogen peroxide as a terminal oxidant

Amphiphilic flavinium salt [10-dodecyl-5-ethyl-3,7,8-trimethylisoalloxazinium perchlorate ( 1b)], solubilized in micelles of sodium dodecyl sulfate (SDS), hexadecyltrimethylammonium chloride (CTAC), hexadecyltrimethylammonium nitrate (CTANO 3) or Brij 35, catalyzes the chemoselective oxidation of thioanisole ( 2) to its corresponding sulfoxide 4. The sulfoxidation rates observed in micelles in the presence of 1b exceeded, in most instances, those of the reactions catalyzed by its hydrophilic homologue [5-ethyl-3,7,8,10-tetramethylisoalloxazinium perchlorate ( 1a)] in homogeneous solutions. Reaction rates were strongly dependent on the type of micellar matrix and on the pH value. The highest acceleration rate was found in SDS micelles at pH 4.4 (TOF = 3 × 10 3 h −1). In our experiments, micelles favoured the catalytic process rather than the non-catalyzed reaction, this effect being especially pronounced in cationic micelles, for which the non-catalyzed reaction was markedly suppressed. The ratio v cat / v 0 of the catalyzed and non-catalyzed reaction rates was almost 40 in CTANO 3, while in homogeneous solution its value did not exceed 7.

Modulation of photophysics of 2-hydroxy 1-naphthaldehyde in non-ionic micelles

Interesting structural influence of different types of non-ionic micelles (Tween-40, Tween-80, Brij-30 and Brij-78) on the excited state proton transfer photophysics of 2-hydroxy 1-naphthaldehyde has been investigated. Anion band formation in the excited state is favored in Brij micelles, similar to aqueous environment due to hydrogen bonding ability of OH group in Brij but the same is hindered in Tween micelles. Quantum chemical calculations predicted, with free energy and enthalpy values, two possible anionic conformers ( cis and trans). One of the two anionic conformers is favored in Brij 30 and addition of base seems to lower the barrier for other conformer to appear.

The Location of Phenolic Antioxidants and Radicals at Interfaces Determines Their Activity

To characterize parameters influencing the antioxidant activity at interfaces a novel ESR approach was developed, which facilitates the investigation of the reaction stoichiometry of antioxidants towards stable radicals. To relate the activity of antioxidants towards the location of radicals at interfaces NMR experiments were conducted. Micellar solutions of SDS, Brij and CTAB were used to model interfaces of different chemical nature. The hydrophilic Fremy's radical was found to be solubilized exclusively in the aqueous phase of SDS micellar solution but partitioned partly into the hydrophilic headgroup area of Brij micelles. In contrast the hydrophobic galvinoxyl was exclusively located in the micellar phase with the increasing depth of intercalation in the order SDS < Brij < CTAB. Gallates revealed a higher stoichiometric factor towards galvinoxyl in CTAB systems, which is accounted to a concentration effect of antioxidant and radical being both solubilized in the palisade layer. In contrast, in SDS solutions hardly any reaction between galvinoxyl and gallates was found. SDS acted as a physical barrier between radical (palisade layer) and antioxidant (stern layer). The influence of the hydrophobic properties of the antioxidant was clearly seen in Brij micelles. Elongation of the alkyl chain in gallate molecule resulted in increasing stoichiometric factors in the presence of galvinoxyl being located in the deeper region of the bulky headgroup area. The reverse trend was found in the presence of Fremy's radical being located in the hydrated area of the micelles.

Investigating the Location of Propyl Gallate at Surfaces and Its Chemical Microenvironment by 1H NMR

The location and the resulting chemical microenvironment of the antioxidant propyl gallate (PG) was studied in micellar solutions using the cationic emulsifier cetyl trimethyl ammonium bromide (CTAB), the anionic emulsifier sodium dodecyl sulphate (SDS) and the non-ionic emulsifier Brij 58 (polyoxyethylene-20-cetyl ester). T (1) relaxation time of the aromatic protons of PG was investigated in micellar solutions and compared with that in aqueous solution in the absence of emulsifier. The relaxation time of the PG portion that is solubilized in the micelle (T (1,eff)) was calculated from the partition behavior of PG in micellar solution. From the 1D-(1)H spectrum, the alteration in the electron density of the aromatic protons and the alteration in the peak shape of the emulsifier headgroup and alkyl chain proton signals were indicative of the location of propyl gallate in the different micelles. Nuclear Overhauser effects (NOE) made it possible to deduce the exact location of PG by calculation of the relative NOEs. Marked differences were found for the location of PG in CTAB, SDS and Brij 58 micelles. PG was found to be located in the palisade layer of CTAB micelles, in the region of the polyoxyethylene chain of Brij micelles and in the Stern layer of SDS micelles. For careful study of the location of antioxidants and therefore to be able to characterize the chemical microenvironment of the antioxidants is crucial for understanding differences in antioxidant activities as a function of lipid surfaces. The application of spectroscopic methods may help to optimize the antioxidant activity to inhibit lipid oxidation at surfaces that are formed in a wide range of foods (emulsions), cosmetics, pharmaceuticals (emulsions and carrier systems) and of biological membranes (LDL-particles).

Spectroscopic Investigations on the Interaction of Crystal Violet with Nonionic Micelles of Brij and Igepal Surfactants in Aqueous Media

The behavior of the triphenylmethane dye crystal violet in aqueous solutions containing polyoxyethylene nonionic surfactants was investigated using absorption and fluorescence spectroscopic techniques. The interactions of the dye were examined in micellar media in order to prevent dye aggregation and to ensure maximum dye and surfactant interaction. The relative fluorescence enhancements and the binding constants of the dye to the surfactant micelles were determined. The micropolarities of the micellar environment sensed by the pyrene probe were estimated from the I 1/I 3 intensity ratios of the fluorescence spectra of pyrene. The fluorescence quenching of pyrene by hexadecylpyridinium chloride was investigated in aqueous surfactant mixtures at a fixed concentration of surfactant in order to determine the aggregation numbers. Attempts were made to correlate the binding constants obtained in this investigation to various micellar parameters.