Nonmicellar Self-Association of Propantheline Bromide:  Effect of the Column Length on the Chromatogram

Funasaki, Noriaki; Uemura, Yasuko; Hada, and Sakae; Neya, Saburo

doi:10.1021/la9505273

Cited by 8 publications

(26 citation statements)

References 33 publications

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“…This value is similar to 13, 20, 30, and 30 M Ϫ1 determined by gel filtration chromatography, 29) NMR, 25) surface tension, 17) and UV spectra, 17) respectively. The 1 : 1 binding constants of PB with a-, b-, and g-CyDs (Table 1) are close to those already determined by measurements of the NMR chemical shift, 25) the surface tension, and the UV absorbance.…”

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Masking Mechanisms of Bitter Taste of Drugs Studied with Ion Selective Electrodes

et al. 2006

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The masking mechanisms of the bitter taste of propantheline bromide (PB) and oxyphenonium (OB) bromide by native and modified cyclodextrins, saccharides, surfactants, organic acids, nonionic and anionic polymers, and other compounds were investigated with ion selective electrodes. The intensity of the bitter taste for a mixed solution of cyclodextrin with PB or OB was quantitatively explained from the observed electromotive force with the following assumptions: the complex and the masking agent do not have any tastes and the bitter taste is independent of other tastes. Sodium dodecyl sulfate reduced the bitter taste remarkably, and this reduction was also explicable on the basis of the same mechanism. Sodium taurodeoxycholate enhanced the bitter taste, because of its strong bitterness, although it formed 1 : 1 complexes with PB and OB. The masking mechanism of saccharides was ascribed to overcoming the weak bitterness of the drug by the strong sweetness. l l-Carrageenan suppressed the bitter taste remarkably. This suppression was ascribed to the binding of PB and OB to l l-carrageenan, the effect of the solution viscosity on the bitter taste, and the covering of the bitter taste receptor by l lcarrageenan. It was suggested that the moderate masking by other polymers was attributable to the effect of the solution viscosity or the receptor covering. Native and modified b b-cyclodextrins, sodium dodecyl sulfate, l l-carrageenan, Tween 20, and sodium carboxymethyl cellulose are good masking agents for the bitter tastes of PB and OB. The drug ion selective electrode is a useful tool for understanding of the masking mechanism of the bitter taste, screening of masking agents, and estimation of appropriate concentrations of the masking agents.

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Masking Mechanisms of Bitter Taste of Drugs Studied with Ion Selective Electrodes

et al. 2006

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“…This difference in cmc is explicable on the basis of electrostatic effects of the salt. PB self-associates stepwise to form dimer and higher multimers . Figure illustrates the concentration dependence of the changes in chemical shifts of the xanthene ring protons.…”

Section: Resultsmentioning

confidence: 99%

“…Recently, we have investigated the self-association pattern of the antiacetylcholine drug, propantheline bromide (PB), by gel filtration chromatography. PB self-associates stepwise to form dimer and larger multimers . Although PB is a bitter drug, its bitterness is depressed by the addition of α-, β-, and γ-cyclodextrin (CyD).…”

Section: Introductionmentioning

confidence: 99%

Dimerization and α-Cyclodextrin Inclusion of Propantheline Bromide as Studied by NMR and Molecular Modeling

et al. 1999

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The proton chemical shifts of propantheline bromide (PB) and α-cyclodextrin (α-CyD) are determined as a function of the PB concentration in the absence and presence of 5 mmol dm-3 α-CyD. The dimerization constant and the critical micelle concentration of PB are determined to be 20 dm3 mol-1 and 18 mmol dm-3. The chemical shift variations of PB protons induced with the dimerization of PB agree very well with the values calculated on the basis of the antiparallel stacking of two xanthene rings. The 1:1 binding constant and the chemical shifts of PB and α-CyD protons for their complex are evaluated from the concentration dependence of the chemical shifts. On the basis of both these shift data and molecular mechanical calculations, it is estimated that one of the benzene rings of PB in the complex is included shallowly from the wider side into the α-CyD cavity. The chemical shifts of the α-CyD protons, calculated on the basis of the effect of the xanthene ring current for this structure, agree excellently with the observed ones.

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“…5,6 Under these conditions the surface tension of an aqueous solution of PB and one of the CDs is determined by the concentration of the uncomplexed monomer of PB. Propantheline bromide self-associates to form the dimer and higher aggregates, and the formation constants of these aggregates have been determined by chromatography at 298 K. 13 The dimerization of PB is the most important multimer over Table 1. the PB concentrations investigated in the present work. The effects of the higher multimerizations on the equilibrium constants are negligible (data not shown).…”

Section: Surface Tensions and Bitter Taste Intensities Of Aqueousmentioning

confidence: 99%

Reduction of the Bitter Taste Intensity of Propantheline Bromide by Cyclodextrins As Predicted by Surface Tension Measurements

et al. 1996

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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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Nonmicellar Self-Association of Propantheline Bromide: Effect of the Column Length on the Chromatogram

Cited by 8 publications

References 33 publications

Masking Mechanisms of Bitter Taste of Drugs Studied with Ion Selective Electrodes

Masking Mechanisms of Bitter Taste of Drugs Studied with Ion Selective Electrodes

Dimerization and α-Cyclodextrin Inclusion of Propantheline Bromide as Studied by NMR and Molecular Modeling

Reduction of the Bitter Taste Intensity of Propantheline Bromide by Cyclodextrins As Predicted by Surface Tension Measurements

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