The surface tension and the bitter taste intensity of aqueous solutions of propantheline bromide alone and of complexes with R-, -, and γ-cyclodextrin have been determined, and a unique correlation between these quantities has been found to hold regardless of the kind and concentration of the cyclodextrin. The surface tension of an aqueous solution of propantheline bromide increases on addition of one of the cyclodextrins, and the effectiveness in surface tension enhancement decreases in the order -, γ-, R-cyclodextrin. Analysis of these surface tension data yields the equilibrium constants of 1:1, 1:2, and 2:1 complexations of propantheline bromide and R-, -, γ-cyclodextrin. These binding constants are in excellent agreement with those estimated by spectrophotometry. As well as the equimolar complex, -cyclodextrin forms the 1:2 complex, and γ-cyclodextrin forms the 2:1 complex. The dimer of propantheline bromide can be incorporated into γ-cyclodextrin. Although the dimer is not included into R-and -cyclodextrins, the extent of complexation is decreased by the dimerization. The bitter taste of propantheline bromide is suppressed by adding one of the cyclodextrins. The order of this suppression agrees with that of surface tension enhancement. From the relationship between the surface tension and the bitter taste intensity of aqueous solutions of propantheline bromide and the observed value of surface tension for an aqueous solution of propantheline bromide and one of the cyclodextrins, we can predict the bitter taste intensity of the mixed solution. Molecular models of some complexes of propantheline bromide and cyclodextrins have been proposed on the basis of size and shape of these molecules and the affinity of each group of propantheline bromide to the cyclodextrin cavity.

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The self-association behavior of propantheline bromide in a 154 mmol dm -3 sodium bromide solution has been investigated by frontal chromatography on two Sephadex columns and by the surface tension method. Analysis of centroid volume data by asymptotic theory yields the monomer concentration of propantheline bromide as a function of its total concentration. Further analysis of the concentration dependence of the monomer concentration by a multiple equilibrium model provides weight-average and number-average aggregation numbers. The aggregates of propantheline bromide are small and are formed in a stepwise manner without a cmc. Stepwise aggregation constants for propantheline bromide are estimated and are used to predict the aggregate size distribution. Derivative chromatograms support the above results based on the centroid volume data. For instance, the shape of the derivative chromatogram of propantheline bromide at the trailing boundary is closer to that of penicillin V than to that of the surfactant, suggesting that propantheline bromide self-associates in a nonmicellar mode. The dimerization constant of propantheline bromide estimated from the trailing peak volume is close to that obtained from the centroid volume. The shape of the frontal chromatogram is almost independent of the size of the column. This fact indicates that our chromatographic method for investigating the self-association behavior is reliable. The surface tension of the propantheline bromide solution has a transition, albeit diffuse, when plotted against the logarithm of the total concentration and decreases gradually with increasing concentration above this transition. A reasonable molecular area of propantheline bromide on the aqueous surface is obtained by using the monomer concentration, determined by the chromatographic data, in the Gibbs adsorption equation.

ABSTRACT:Resins containing phosphonium groups were prepared by reaction of chlorohydroxylated glycidylmethacrylate-divinylbenzene macroreticular resins with three trialkylphosphines. Triethylphosphine, tributylphosphine, and trioctylphosphine were used as trialkylphosphines. Adsorption and elution behavior of sodium benzenesulfonate (SBS) and sodium dodecylbenzenesulfonate (SDBS) on the resins were studied. Adsorption of SBS and SDBS increased with increasing the alkyl chain length of phosphonium groups in the resins. The adsorption of SBS decreased with increasing ionic strength of the solution, while the adsorption of SDBS increased with increasing ionic strength of the solution.

ABSTRACT:Copolymer beads (RCCS-4G) with many chloromethyl groups were prepared by treating macroreticular chloromethylstyrene-tetraethyleneglycol dimethacrylate (4G) copolymer beads with chloromethylether. Copolymer beads (RAAS-4G) with benzylamino groups were prepared by treating RCCS-4G with potassium phthalimide. Then the copolymer beads containing phenol derivatives were prepared by treating RAAS-4G with p-hydroxybenzoic acid ( pHBA), 2,4-dihydroxybenzoic acid (DHBA), and 3,4,5-trihydroxybenzoic acid (gallic acid, GA) in N,N-dimethylformamide. The antibacterial activity of the obtained resins was examined against Escherichia coli and Staphylococcus aureus. Resins containing phenolic hydroxy groups of 2.3-7.7 mequiv/g were obtained. Antibacterial activity of the resins containing various phenol derivatives against E. coli or S. aureus increased in the order of RAAS-4G-GA ú RAAS-4G-DHBA ú RAAS-4G-pHBA. The resins containing phenol derivatives exhibited higher antibacterial activity against E. coli than against S. aureus and high activity even against bacteria in NaCl solution. Scanning electron micrographs showed that high antibacterial activity was brought about by the phenolic hydroxyl groups in the resin.