Cetyl Sulfate Research Articles

Oral Sustained Release of a Hydrophilic Drug Using the Lauryl Sulfate Salt/Complex.

The objective of this study was to establish the key factor of the lauryl sulfate (LS) salt/complex for sustained release of a hydrophilic drug at various physiological pH levels. Mirabegron is a hydrophilic drug that exhibits pH-dependent solubility. Sodium lauryl sulfate (SLS) bound to mirabegron in a stoichiometric manner. The formation of the LS salt/complex significantly reduced mirabegron solubility and helped achieve sustained release of mirabegron over a wide range of pH levels. In addition to SLS, other additives containing a sulfate group formed salts/complexes with mirabegron and reduced its solubility at different pH levels. Furthermore, octyl sulfate (OS), myristyl sulfate (MS), and cetyl sulfate (CS) salts/complexes, which contain alkyl chains of different lengths, showed a lower solubility than mirabegron and promoted sustained release of mirabegron. The rank order of solubility and dissolution rate were as follows: OS salt/complex>LS salt/complex>MS salt/complex>CS salt/complex, which corresponded to the rank of alkyl chain lengths. We conclude that the presence of a sulfate group and the length of the alkyl chain are key factors of the LS salt/complex for sustained release of a hydrophilic drug at various physiological pH levels.

Final Report on the Safety Assessment of Sodium Cetearyl Sulfate and Related Alkyl Sulfates as Used in Cosmetics

Sodium cetearyl sulfate is the sodium salt of a mixture of cetyl and stearyl sulfate. The other ingredients in this safety assessment are also alkyl salts, including ammonium coco-sulfate, ammonium myristyl sulfate, magnesium coco-sulfate, sodium cetyl sulfate, sodium coco/hydrogenated tallow sulfate, sodium coco-sulfate, sodium decyl sulfate, sodium ethylhexyl sulfate, sodium myristyl sulfate, sodium oleyl sulfate, sodium stearyl sulfate, sodium tallow sulfate, sodium tridecyl sulfate, and zinc coco-sulfate. These ingredients are surfactants used at concentrations from 0.1% to 29%, primarily in soaps and shampoos. Many of these ingredients are not in current use. The Cosmetic Ingredient Review (CIR) Expert Panel previously completed a safety assessment of sodium and ammonium lauryl sulfate. The data available for sodium lauryl sulfate and ammonium lauryl sulfate provide sufficient basis for concluding that sodium cetearyl sulfate and related alkyl sulfates are safe in the practices of use and concentration described in the safety assessment.

The Effect of Synergism Behavior in Binary Mixtures of Some Surfactants with Ethyl Xanthat Absorbed on Clay for Wastewater Treatment

Surface tension, sedimentation, and turbidity experiments were conducted in order to study the synergism behavior of some surfactants with ethyl xanthat mixtures on the reduction of surface tension of their aqueous solutions and on the hydrophilicity of clay surface for using it as absorbent to oil in wastewater treatment. The following systems were studied: 1) potassium ethyl xanthat (KEX) with sodium cetyl sulphate (SCS); 2) potassium ethyl xanthat with cetyl trimethyl ammonium bromide (CTAB); and 3) potassium ethyl xanthat with ethoxylated palmetic acid (EPA). A synergistic effect of the combined reagents was found to enhance the hydrophilicity of clay and also to reduce the surface tension depending mainly on the surface properties of the mixtures.

Spontaneous Formation of Vesicles and Dispersed Cubic and Hexagonal Particles in Amino Acid-Based Catanionic Surfactant Systems

Mixed catanionic surfactant systems based on amino acids were investigated with respect to the formation of liquid crystal dispersions and the stability of the dispersions. The surfactants used were arginine-N-lauroyl amide dihydrochloride (ALA) and N(alpha)-lauroyl-arginine-methyl ester hydrochloride (LAM), which are arginine-based cationic surfactants; sodium hydrogenated tallow glutamate (HS), a glutamic-based anionic surfactant; and the anionic surfactants sodium octyl sulfate (SOS) and sodium cetyl sulfate (SCS). It is demonstrated that in certain ranges of composition there is a spontaneous formation of vesicular, cubic, and hexagonal structures. The solutions were characterized with respect to internal structure and size by cryogenic transmission electron microscopy (cryo-TEM), dynamic light scattering (DLS), and turbidity measurements. Vesicles formed spontaneously and were found for all systems studied; their size distribution is presented for the systems ALA/SCS/W and ALA/SOS/W; they are all markedly polydisperse. The aging process for the system ALA/SOS/W was monitored both by turbidity and by cryo-TEM imaging; the size distribution profile for the system becomes narrower and the number average radius decreases with time. The presence of dispersed particles with internal cubic structure (cubosomes) and internal hexagonal structure (hexosomes) was documented for the systems containing ALA and HS. The particles formed spontaneously and remained stably dispersed in solution; no stabilizer was required. (Cubosome and hexosome are USPTO registered trademarks of Camurus AB, Sweden.) The spontaneous formation of particles and their stability, together with favorable biological responses, suggests a number of applications.

Enhanced enantioselectivity and remarkable acceleration on the lipase-catalyzed transesterification using novel ionic liquids

Novel imidazolium salt ionic liquids were prepared derived from polyoxyethylene(10) cetyl sulfate and used as an additive for lipase-catalyzed transesterification in organic solvent; a remarkable enhanced enantioselectivity was obtained when the salt was added in 3 to 10 mol% vs. substrate in the Pseudomonas cepacia lipase-catalyzed transesterification of 1-phenylethanol using vinyl acetate in a diisopropyl ether or hexane solvent system. There was a remarkable acceleration when the lipase was coated with this novel ionic liquid and used as catalyst for transesterification in i-Pr2O or in hexane.

Characterization and quantitation of apolipoprotein B-100 by capillary electrophoresis

The interaction of low density lipoproteins (LDL) with different surfactants was studied by capillary electrophoresis (CE) and sucrose density gradient ultracentrifugation as part of developing a method for quantitation of apoB-100 in serum. A mixture of surfactants consisting of 70% sodium dodecyl sulfate (SDS), 25% sodium myristyl sulfate, and 5% sodium cetyl sulfate was found to delipidate LDL particles more effectively than pure SDS or sodium decyl sulfate. The delipidation products of LDL [apolipoprotein B-100 (apoB-100) and lipids] were resolved as two distinct peaks by CE when using a 3.5 mm 70% SDS mixture, 20% (v/v) acetonitrile, 50 mm sodium borate, pH 9.1 buffer. This CE method was also used to characterize apoB-100 derived from samples of lipoprotein [a] and very low density lipoproteins (VLDL). A CE-based quantitation method for apoB-100 was developed utilizing the observed linear relationship between apoB-100 concentration and its corrected 214 nm absorbance peak area measured on-line by CE. Concentration values of apoB-100 in LDL and VLDL samples were determined by CE and found to be accurate when compared to values obtained by immunoturbidimetric analysis and the Lowry method. Capillary electrophoresis can be used as a precise, accurate, and specific on-line method for the qualitative and quantitative analysis of the apoB-100 component of VLDL and LDL-related lipoproteins.—Cruzado, I. D., S. L. Cockrill, C. J. McNeal, and R. D. Macfarlane. Characterization and quantitation of apolipoprotein B-100 by capillary electrophoresis. J. Lipid Res. 1998. 39: 205–217.

The Effect of Surfactants on the Rate of Decarboxylation of p-Aminosalicylic Acid in Acidic Aqueous Solutions

p-Aminosalicylic acid, which exists in four ionic forms and whose decarboxylation is well known, was used as a model drug to investigate the effects of surfactants with different charges on its stability. The greatest reduction in the rate of decarboxylation at 50°C occurred when the charge on the micelles was opposite to that of the charge on the drug or when both the drug and the micelle had a neutral charge. Thus, at the highest surfactant concentration, 3 or 5% (w/v), there was a 59% reduction in the rate at pH 2.68 in the presence of the nonionic surfactant polyoxyethylene 24 monocetyl ether, 69% reduction in the rate at pH 4.88 in the presence of the cationic surfactant hexadecyl trimethylammonium bromide, and a 43% reduction at pH 1.01 in the presence of the anionic surfactant sodium cetyl sulfate. The decrease in the rate of decarboxylation was attributed to the partitioning of the drug into the micelles, which provided a phase for improved stabilization. Partition coefficients and rate constants for decarboxylation of the drug inside the micelles were calculated.

8 Final Report on the Safety Assessment of Sodium Cetearyl Sulfate

Sodium Cetearyl Sulfate is the sodium salt of a mixture of cetyl and stearyl sulfate which is used as a surfactant and cleansing agent in cosmetics at concentrations ranging from ≥ 0.1 to 25.0%. The LD50 was not achieved in two studies in which rats received a single oral dose of 5.0 ml/kg. In ocular irritation tests, 20.0% aqueous Sodium Cetearyl Sulfate was not irritating to the eyes of rabbits. Twenty percent Sodium Cetearyl Sulfate was not irritating to the skin of rabbits. In a guinea pig sensitization study, Sodium Cetearyl Sulfate was not a sensitizer. Sodium Cetearyl Sulfate is less irritating to the skin than Sodium Lauryl Sulfate, whose safety test data are summarized in the report. Due to the chemical similarity of these two cosmetic ingredients, the safety test data on Sodium Lauryl Sulfate was considered to be applicable to the safety evaluation of this ingredient. On the basis of the animal and clinical data on Sodium Cetearyl Sulfate and Sodium Lauryl Sulfate as presented in the report, it is concluded that Sodium Cetearyl Sulfate is safe as a cosmetic ingredient in the present practices of use and concentration.

The effect of electrolytes on the cloud point of mixed solutions of polypropylene glycol and ionic surfactants

The cloud points of polypropylene glycol (PPG) in the presence of small amounts of ionic surfactants, including dodecyltrimethylammonium bromide (DTAB), cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS) and sodium cetyl sulfate (SCS) have been determined. The results show that the cloud point of PPG will be elevated if a certain amount of ionic surfactant is added. The longer the hydrocarbon chain length of the ionic surfactant homologues, the stronger the effect is, and the effect of anionic surfactants is stronger than that of cationic surfactants with the same hydrocarbon chain length. On the other hand, the cloud point remains unaltered on addition of the same amount of inorganic salt. However, when salts are added to the PPG solution in the presence of a certain amount of ionic surfactants, the cloud point decreases in a ratio depending on the concentration of salts, the nature of the ions and, particularly, the valency of the ions with charges opposite in sign to the charges of the surface-active ion. For systems of 0.01% PPG + SCS and 0.1% PPG + SCS, the valency of the cation of salts is decisive, and the order of the effect is: 1/3 LaCl 3 > 1/2 CaCl 2, > NaCl. For the system of 0.1% PPG + CTAB, the valency of the anion of electrolytes plays the dominant role, and the order of the depressing effect is: 1/3 K 3Fe(CN) 6 > 1/2 Na 2SO 4 > NaBr. For the system of 0.01% PPG + CTAB, a striking phenomenon was observed, i.e. the cloud point was enhanced rather than decreased by the addition of electrolytes. An explanation in terms of the enhancing adsorption of surface-active ions on the PPG chains due to the addition of electrolytes was suggested.

Conductivity and diffusion measurements in micellar and o/w microemulsion systems. A comparative study

Diffusion and conductance measurements have been carried out in two oil/water microemulsions composed of mineral oil/sodium cetyl sulfate (SCS)/n-pentanol/H 2O and hexadecane/cetyltrimethylammonium bromide (CTAB)/n-butanol/H 2O. The measurements were performed over a range of phase volume and temperature of 26–88% and 18–45°C, respectively. Similar data were obtained for the two binary systems sodium dodecyl sulfate (SDS)/H 2O and CTAB/H 2O under comparable conditions of surfactant concentration and temperature. An oil-soluble electroactive species, 1-dodecyl-4-cyanopyridinium iodide, was used to measure diffusivities of micelles and microemulsion droplets. All measurements were made in absence of additives. The data show that microemulsions behave quite differently from their binary surfactant analogs. Based on a simple model, the hydrodynamic radius, the degree of dissociation and the apparent aggregation number were estimated from the diffusion coefficient and conductivity data.

The Photoreduction of Thionine and Surfactant Thionine by Iron(II) in Anionic Micelles and Microemulsions

AbstractThe rate constants for the iron(II)‐thionine and surfactant thionine system have been determined in aqueous solution, sodium dodecyl sulfate (SDS) micelles, and in a mineral oil‐in‐water microemulsion stabilized by sodium cetyl sulfate (SCS) and 1‐pentanol. The triplet lifetimes are all in the range 7–9 μs. The rate constant for electron transfer quenching of triplet thionine by iron(II) is higher in the anionic media due to a higher local Fe2+ concentration. However, the back reaction between semithionine and iron(III) is not similarly enhanced in the presence of micelles or microemulsion. The dismutation of semithionine is a little slower in microemulsion than in water, but over two orders of magnitude slower in SDS micelles. The quantum yield of thionine triplet formation, determined for surfactant thionine in SCS microemulsion, approaches unity.

Equilibrium vapor pressure in microemulsions: a test of the pseudophase model

The thermodynamic activities of oil (benzene) and alcohol cosurfactant have been determined in benzene/sec-butanol/water/surfactant microemulsions. The surfactants employed were sodium cetyl sulfate (anionic), cetyl trimethylammonium bromide (cationic), and Brij 96 (nonionic). The activities were determined by means of gas chromatographic headspace analysis. The results are interpreted in terms of the pseudophase model for microemulsions. The ionic systems appear to fit the model over most of the compositions in the microemulsion range of existence, while the nonionic system does not. For the ionic systems, the distribution of components among the domains of the microemulsion has been calculated.

DIFFUSION MEASUREMENTS IN MICROEMULSIONS

ABSTRACT We have carried out diffusion coefficient measurements in both aqueous micelles and microemulsions using the techniques of palaeography and quasielastic light scattering (QLS) The former method involves the determination of the diffusion coefficient of an electroactive oil soluble probe at a polarizable microelectrode. For high water content microemulsions, both methods yield the same diffusion coefficients, which can be identified as the self diffusion coefficient For cetyltrimethylammonium bromide (CTAB) micelles, both methods yield the same result at the salt (NaBr) concentration at which the QLS measurements are independent of CTAB concentration. In more concentrated microemulsions, QLS data gave diffusion coefficients in agreement with polarography only for a sodium cetyl sulfate (SCS) system at 65-75 wt % water. For the SCS microemulsions at 60% water, and CTAB microemulsion at 60-75% water, the QLS data yielded rapid, nonexponential decays. However, consistent polarographic diffusion coeff...

Effect of alkyl chain on the uptake, distribution, and excretion of 35S-labeled alkyl sulfates in carp

The effect of the number of carbons of the alkyl chain on the uptake, distribution, and excretion of a surfactant in fish was investigated using 35S-labeled alkyl sulfates ( 35SAS) of three different carbon numbers and carp. As a result, the radioactivity was found to be easily taken up into the fish body and distributed throughout the tissues and organs for any surfactant, but the concentration factors differed characteristically depending upon the number of carbons of the alkyl chain, i.e., 2.1, 11, and 73 for 35S-labeled sodium lauryl sulfate ( 35S-C12-AS), 35S-labeled sodium myristyl sulfate ( 35S-C14-AS), and 35S-labeled sodium cetyl sulfate ( 35S-C16-AS), respectively. And the distribution profile and excretion rate also tended to be affected by the number of carbons of the alkyl chain.

Hepatotoxic and cellular uptake interactions among surface active components of erythromycin preparations

Rat hepatoma cell cultures and Chang cell cultures derived from human liver were exposed to erythromycin estolate, erythromycin cetyl sulfate or to the individual components of these preparations, erythromycin propionate and sodium lauryl sulfate or erythromycin base and sodium cetyl sulfate respectively. Cytotoxicity was evaluated by leakage of cytoplasmic and lysosomal enzymes into the media. The uptake of the drugs by the cells was measured with radiolabeled compounds. The surface activity of the drugs was determined in vitro with a surface tension balance. Those drugs with the greatest surface activity were found to have the greatest cytotoxic effects on both cell culture lines. The cytotoxic effects of erythromycin cetyl sulfate were exclusively from the cetyl sulfate. With the erythromycin estolate combination, both lauryl sulfate and erythromycin propionate were cytotoxic. The presence of the latter increased the uptake of lauryl sulfate by the cells and resulted in a potentiation of the cytotoxic effect. Thus, the detergent ingredients used to enhance the gastrointestinal absorption of the drugs may also enhance their cell penetration and determine their hepatotoxicity in vitro; this form of cytotoxic drug interaction mechanism at the cellular level may explain the hepatotoxicity of some of these drugs in man.

Liver cell culture toxicity and surfactant potency of erythromycin derivatives

When Chang liver cell cultures were exposed to a new erythromycin salt, erythromycin cetyl sulfate, and other marketed erythromycin derivatives (erythromycin base, stearate, and estolate) only the cetyl sulfate and estolate salts had cytotoxic effects. Both compounds were very active in lowering surface tension which suggests a possible relationship between this physiocochemical property and their cytotoxic potential in vitro. These in vitro results correlate with the known differences in clinical hepatotoxic potential of the marketed erythromycin derivatives and suggest the possible usefulness of this method for cytotoxicity screening of newly developed therapeutic drugs.

Kinetics and Mechanisms of Monolayer Interactions I: Cetyl Sulfate and Cetrimonium Ions Interacting with Dipalmitoyl Lecithin and Dipalmitoyl Glycerol

The interaction of cetyl sulfate and cetrimonium (cetyltrimethylammonium) ions with dipalmitoyl lecithin and dipalmitoyl glycerol monolayers spread at the air/water interface was followed by the variation of the surface pressure and surface potential. The kinetics and the final equilibrium varied with the nature of the injected surfactant. An approximative method was devised to calculate the energies of activation, which are comparable with others obtained on a classical thermodynamic basis for cetyl alcohol monolayers interacting with sodium lauryl sulfate. The presence of the phosphoryltrimethylethanolamine group in the dipalmitoyl lecithin molecule decreases to some extent the interaction with cetyl sulfate and cetrimonium ions. The values of the energies of activation obtained indicate that the ionic groups of the polar moiety of dipalmitoyl lecithin are not equivalent in the perturbation that an attached hydrocarbon chain produces in the surface pressure of the monolayer. This difference may be explained by the different mobilities that a hydrocarbon chain would have when attached to one or the other ionic attraction centers because of the unrestricted movement of the positively charged trimethylammonium group around the phosphate linkage of the dipalmitoyl lecithin. Some implications of this observation to microstates of biomembranes are suggested.

The uptake of cetyltrimethylammonium bromide by Escherichia coli

Abstract THE uptake of cetyltrimethylammonium bromide (CTAB) by bacteria has previously been examined by Salton (1951) and by McQuillen (1950). Both workers determined its concentration in solutions by titration with sodium cetyl sulphate using pinacyanol bromide as indicator, and reported that uptake was in the form of a typical adsorption isotherm with saturation of the cells at an uptake equivalent to several theoretical close packed monolayers. This communication reports on studies of the uptake of 14C-labelled CTAB by cells of Escherichia coli and the concurrent release of phosphorus compounds from their metabolic pool.

Adsorption from aqueous solutions of ionic surface-active agents by gold. Part 2

The extent of adsorption by gold from aqueous solutions of a series of long-chain ammonium bromides has been measured and electrokinetic properties of gold in these solutions studied by microelectrophoresis. Froth flotation of gold particles has been studied in solutions of long-chain ammonium bromides, of long-chain pyridinium bromides and of the anionic compounds sodium cetyl sulphate and sodium dodecyl sulphate. In part 1, conclusions were drawn from adsorption and electrophoretic data regarding the modes of orientation of surfactant ions in the adsorbed layers; specific adsorption of surfactant anions but not of cations was postulated. The relative efficiencies of flotation reported here support those conclusions.

STUDIES ON DECOMPOSITION AND STABILIZATION OF DRUGS IN SOLUTION. XV. HYDROLYSIS OF SODIUM OCTYL, MYRISTYL, CETYL, AND PENTADECANE-8-SULFATES.

The hydrolysis of sodium octyl (SOS), myristyl (SMS) and cetyl sulfate (SCS) as sodium lauryl sulfate (SLS) homologue and that of sodium pentadecane-8-sulfate (SPS) as secondary alcohol sulfate in hydrochloric acid solution were studied. 1) It was recognized that the sodium alkyl sulfates were relatively stable below their critical micelle concentration (CMC) and less stable above their CMC as well as SLS. Accordingly, this phenomenon was ascribed to the micellization and the ionic atmosphere around the micelle of the sodium alkyl sulfate. 2) The sodium normal alkyl sulfate with the longer alkyl chain length was less stable than the shorter chain length. It was thought that the micelle with the longer alkyl chain length was more affected by gegen-ion than the shorter chain length.