Cetylpyridinium Chloride Complexes Research Articles

Interaction of metanil yellow dye with cationic surfactants: Conductometric and spectroscopic studies

Conductometric and spectroscopic methods were used to examine the interactions among the cationic surfactants, tetradecyltrimethylammonium bromide (TTAB) and cetylpyridinium chloride (CPC), and the anionic azo dye metanil yellow (MY) in an aqueous solution. The standard Gibb’s energy (ΔGm0), enthalpy (ΔHm0), and entropy (ΔSm0) of micellization were determined with the help of the equilibrium model. With temperature rise, the critical micelle concentration (cmc) increases because of the interruption of the organized water (WR) molecules enclosing the surfactant’s hydrophobic groups. As the total carbon atoms of the hydrophobic group are more in CPC than TTAB, a considerable fall in cmc value was observed. The presence of MY caused a higher degree of ionization (α) of micelles of TTAB and CPC. The negative values of ΔGm0 and ΔHm0 for both the surfactants in WR and aqueous MY solution (WR-MY) show that the micellization process is spontaneous and exothermic. As indicated by the -TΔSm0 values, which were found to be greater than ΔHm0 values, the entropy gain is typically what regulates the micellization process and the micellization was found to have a negative heat capacity (ΔCp,m0). UV–Visible spectra show that CPC has a higher binding constant (Kb) value as compared to TTAB implying that CPC has a comparatively greater binding affinity with MY dye in aqueous media (WR). The decreasing value of ΔGb for CPC indicates that the chance for the MY–CPC complex formation is more than that of the MY–TTAB complex. As shown by the rise in absorbance values as surfactant concentrations increase, a large number of the MY molecules are attracted to TTAB and CPC micelles.

A novel montmorillonite clay-cetylpyridinium chloride complex as a potential antiamoebic composite material in contact lenses disinfection

BackgroundAcanthamoeba keratitis is a painful, sight-threatening infection. It is commonly associated with the use of contact lens. Several lines of evidence suggest inadequate contact lens solutions especially against the cyst forms of pathogenic Acanthamoeba, indicating the need to develop effective disinfectants. ObjectiveIn this work, the application and assessment of montmorillonite clay (Mt-clay), cetylpyridinium chloride (CPC) and cetylpyridinium chloride-montmorillonite clay complex (CPC-Mt) against keratitis-causing A. castellanii belonging to the T4 genotype was studied. MethodsAdhesion to human cells and amoeba-mediated cytopathogenicity assays were conducted to determine the impact of Mt-clay, CPC and CPC-Mt complex on amoeba-mediated binding and host cell death. Furthermore, assays were also performed to determine inhibitory effects of Mt-clay, CPC and CPC-Mt complex on encystment and excystment. In addition, the cytotoxicity of Mt-clay, CPC and CPC-Mt complex against human cells was examined. ResultsThe results revealed that CPC and CPC-Mt complex presented significant antiamoebic effects against A. castellanii at microgram dose. Also, the CPC and CPC-Mt complex inhibited amoebae binding to host cells. Furthermore, CPC and CPC-Mt complex, were found to inhibit the encystment and excystment processes. Finally, CPC and CPC-Mt complex showed minimal host cell cytotoxicity. These results show that CPC and CPC-Mt complex exhibit potent anti-acanthamoebic properties. ConclusionGiven the ease of usage, safety, cost-effectiveness and long-term stability, CPC and CPC-Mt complex can prove to be an excellent choice in the rational development of contact-lens disinfectants to eradicate pathogenic Acanthamoeba effectively.

Response surface methodology for modelling and determination of catechin in Pistachio green hull using surfactant-based dispersive liquid–liquid microextraction followed by UV–Vis spectrophotometry

A rapid and simple approach for the preconcentration and determination of catechin from pistachio green hull samples has been proposed by surfactant-assisted dispersive liquid–liquid microextraction followed by UV–Vis spectrophotometry (SADLLME/UV–Vis). This method involved the formation of a catechin complex with cetylpyridinium chloride (CPC) as cationic surfactant, and subsequently, DLLME was applied to extract the catechin–CPC complex into chloroform. Different parameters affected the extraction efficiency were optimized by central composite design (CCD) and response surface methodology (RSM). In optimum condition, the calibration curve was linear in the range of 0.4–5 µg mL− 1 of catechin with correlation coefficient of 0.9982. The relative standard deviation based on five replicated analyses of 1 µg mL− 1 catechin was 1.85%. The proposed method was successfully applied for preconcentration and determination of trace amounts of catechin in pistachio hull samples.

Interaction between cetylpyridinium chloride and amino acids: A conductomertic and computational method study

ABSTRACTHerein, we have investigated the interaction between three different amino acids (AA) namely glycine (Gly), threonine (Thr), and alanine (Ala) with cationic surfactant cetylpyridinium chloride (CPC) by conductance measurements and computational method. For pure CPC as well as amino acid–CPC mixtures, three different critical micelle concentrations (c*) were achieved. The values of c* for the AA–CPC mixtures in KCl solution are lesser in comparison to the aqueous solution. The negative values of are obtained in every studied system. The values of and for AA–CPC micellization reveal that both hydrophobic and hydrophilic interactions are the binding forces among CPC molecules and between AA and CPC. Molecular dynamics simulation indicates that the pyridine ring of CPC promotes the non-bonding interaction in AA–CPC complexes. Further quantum calculation revealed that non-conventional CH⋯O hydrogen bonding plays a critical role and stabilizes these complexes.

Study of the Effect of Polyion Charge Density on Structural Properties of Complexes between Poly(acrylic acid) and Alkylpyridinium Surfactants

Structural properties of complexes of poly(acrylate) anion (PA) and the cationic surfactants dodecylpyridinium (DPC) and cetylpyridinium chloride (CPC) were investigated by synchrotron X-ray scattering at various degrees of neutralization αN of poly(acrylic acid) (HPA) and at a fixed surfactant:polymer molar ratio. In all scattering curves, one broad (PA−DPC complexes, all αN-values, and PA−CPC complexes, αN = 0) or several sharp peaks (PA−CPC complexes, αN > 0) were observed, pointing to a high degree of ordering in these systems. The fundamental type of organization of surfactant is in the form of polymer-induced micelles that are clustered around the polymer. The multiple reflections in the case of PA−CPC complexes point to a Pm3n cubic structure. The calculated values of structural parameters indicate a larger degree of ordering in complexes at low αN-values (i.e., at αN < 0.5) than that at higher ones. This suggests that the binding of the surfactant by the polyelectrolyte is influenced by factors ot...

Spectrophotometric determination of samarium(III) with chrome azurol S in the presence of cetylpyridinium chloride

A sensitive, simple method for the determination of trace amounts of samarium by spectrophotometry is described based on the formation of the samarium–chrome azurol S (CAS) complex in micellar medium. The molar absorptivities of the complexes at pH 7.5 at 505 nm were 3.6×10 4 and 1.4×10 5 l mol −1 cm −1 for water media and cetylpyridinium chloride (CPC), respectively. Beer’s law is obeyed from 0.05–2 mg l −1 of samarium at 505 nm as Sm–CAS–CPC complex. Optimal conditions such as reagent amounts, and pH for the samarium determination were reported. The effects of foreign ions were also investigated. The proposed method was successfully applied to the determination of samarium contents in synthetic samples.

Measurement of serum glycosaminoglycans by laser nephelometry

A simple, sensitive micromethod for the assay of serum hyaluronic acid and chondroitin sulphates is presented. The method is based on the binding of the quaternary ammonium salt, cetylpyridinium chloride (CPC) to serum polyanions, and quantitation of the complexes by laser nephelometry. Measurement of the CPC complexes in serum before and after digestion with specific enzymes enables quantitation of hyaluronic acid and chondroitin sulphates in less than 100 μl serum. Using this technique, hyaluronic acid is detectable in a small number of normal human sera at concentrations up to 4 mg/l, and chondroitin sulphates are consistently present at concentrations ranging from 2 to 25 mg/l.

Distribution of glycosaminoglycans across the normal and the scoliotic disc.

This paper reports on our investigations of the glycosaminoglycans (GAGs) (hyaluronic acid, chondroitin-6-sulfate, and keratan sulfate) of 13 adjacent zones of normal and scoliotic discs obtained at necropsy. The isolation and separation of these GAGs on the microgram scale was achieved using the different solubilities of the calcium and cetyl pyridinium chloride complexes. In normal discs the distribution of these GAGs is symmetric about the nucleus pulposus where their concentration is highest, and lowest in the outer annulus regions. A shift in this distribution profile was observed for the GAGs of the scoliotic discs, particularly at the apex of the curve. On the concave side of this disc the chondroitin-6-sulfate was elevated relative to discs at a lower level. In those annulus zones on the convex side of the curve, the keratan sulfate and hyaluronic acid levels were elevated and chondroitin sulfate depressed. These results suggest the presence in these respective regions of at least two different species of proteoglycans accompanied by elevated hyaluronate levels.

Biochemical study of cardiac valvular tissue. The isolation of glycoproteins and proteoglycans from salt-insoluble materials of bovine heart valve

The chemical nature of the various kinds of glycoproteins as well as proteoglycans in bovine heart valve were investigated. Two glycoproteins were isolated by collagenase digestion from the salt-insoluble matrix; the chemical composition of the sugar moieties were different from each other and both were unique in their amino acid composition. The remaining collagenase-insoluble materials were solubilized with 8 m area followed by 0.1 m 2-mercaptoethanol in 8 m urea. Proteoglycans and glycoproteins were separated using both urea- and mercaptoethanol-soluble products treated with cetylpyridinium chloride (CPC). Two corresponding glycoprotein fractions from CPC supernatants were obtained; there was a considerable difference in the chemical composition of both sugar and protein moieties and these results were remarkably different from collagenase-soluble glycoproteins. On the other hand, the CPC complexes which were separated into 2 m CaCl 2 extractable materials were mainly proteoglycans and unextractable residues. The residual fractions were completely solubilized in 4 m guanidine hydrochloride solution. Both fractions consisted mainly of glycoproteins which had similar chemical compositions. In addition, despite the large variation in sugar contents, the amino acid composition of these glycoproteins was very similar to that of “structural glycoprotein,” and “acidic structural protein” isolated by other workers.

Spectrophotometric determination of molybdenic acid and zirconium(IV) with phenylfluorone and cetylpyridinium chloride

In the presence of excess cetylpyridinium chloride (CPC) in an acidic solution molybdenic acid(MoO42-) forms a water soluble complex with phenylfluorone, whose color was very stable. The color development of a water soluble reddish brown complex between phenylfluorone and Zr(IV) enhanced by the catalytic action of sodium fluoride, particluary in the coexistence of excess CPC which increased the absorbance of the complex. Their absorption maximum wavelength were at about 540 nm (MoO42-), 560 nm {Zr(IV)} against the reagent blank, and the coloration was stable over the pH range from 1.2 to 1.9 (pH was adjusted with NaCl glycocohol-HCl buffer solution) and pH range from 4.2 to 5.2 (pH was adjusted CH3COONa-CH3COOH buffer solution). A linear calibration curve was obtained for 460 μg MoO42-/10 ml and 07 μg Zr(IV)/10 ml. According to Sandell's expression the sensitivities were 0.01 μg/cm2 of MoO42- and 0.002 μg/cm2 of Zr(IV) for absorbance of 0.001. From the data, the recommended analytical procedures of MoO42-, and Zr(IV) are as follows.A sample containing 460 μg MoO42- is taken in a 10.0 ml measuring flask, and 1.0 ml of 1.0 × 10-2 M CPC solution, 2.0 ml of buffer solution(pH 1.5), and 2.0 ml of 1.0 × 10-3 M phenylfluorone methanolic solution are added. The solution is diluted to 10.0 ml with water, and allowed to stand at 45°C for 30 minutes, the absorbance of phenylfluorone-MoO42--CPC complex is measured at 540 nm against the reagent blank. To the solution of Zr(IV) is added each 1.5 ml of 1.0 × 10-2 M CPC solution, 0.8 ml of 1.0 × 10-2 M sodium fluoride solution, 1.0 ml of 2.0 × 10-3 M methanolic phenylfluorone solution, and 1.5 ml of buffer solution (pH 4.6). After making up to the volume to 10.0 ml and allowing it to stand for 10 minutes, the absorbance is measured at 560 nm against the reagent. The effects of diverse ions on the absorbance of the complex were examined and shown.

Myocardial connective tissue metabolism in response to injury. II. Investigation of the mucopolysaccharides involved in isoproterenol-induced necrosis and repair in rat hearts.

Myocardial necrosis was produced in rats by administering isoproterenol, and the increase in hexosamine-containing materials in the injured myocardium was investigated. Total hexosamine, galactosamine, neutral sugars, and uronic acids were determined on various fractions isolated from the hearts. Mucopolysaccharides were precipitated as the cetyl pyridinium chloride complex and fractionated according to their solubility in NaCl solutions. Of the hexosamine in the heart, approximately 50% was retained after proteolytic digestion and dialysis. Approximately one-fourth to one-third of the nondialyzable hexosamine was in mucopolysaccharides. The hyaluronic acid fraction of the mucopolysaccharides increased during the early edematous reaction observed in the hearts. The chondroitin sulfate fraction increased in conjunction with the beginning fibrinogenic processes and remained elevated during repair. There was evidence that the glycoproteins may be involved in the myocardial necrosis and repair.

Quantitative isolation of purified acidic glycosaminoglycans from rat skin.

A simple method is proposed for the quantitative isolation of purified glycosaminoglycans from 1- to 3-g samples of rat skin. The cetylpyridinium complex of the polysaccharide is isolated from a clarified papain digest of fresh skin. After recovery of the glycosaminoglycan from the complex, residual protein is removed by treatment, in sequence, with sodium hydroxide, phenol, and trichloroacetic acid. The product contains only small amounts of non-hexosamine nitrogen.The optimal conditions for each step of the procedure were developed by systematic experimentation. The apparent loss of carbazole–borosulfuric chromogen in the formation of cetylpyridinium chloride complex (CPC) seems unlikely to be due to glycosaminoglycan; no other significant losses occurred. The recovery of added glycosaminoglycans was close to theory. The method gave results agreeing well with those for standard published procedures. Trial applications revealed the method to be barely precise enough to distinguish between animals.