Effect of Hofmeister Ions on Transport Properties of Aqueous Solutions of Sodium Hyaluronate

Abstract

Tracer diffusion coefficients obtained from the Taylor dispersion technique at 25.0 °C were measured to study the influence of sodium, ammonium and magnesium salts at 0.01 and 0.1 mol dm−3 on the transport behavior of sodium hyaluronate (NaHy, 0.1%). The selection of these salts was based on their position in Hofmeister series, which describe the specific influence of different ions (cations and anions) on some physicochemical properties of a system that can be interpreted as a salting-in or salting-out effect. In our case, in general, an increase in the ionic strength (i.e., concentrations at 0.01 mol dm−3) led to a significant decrease in the limiting diffusion coefficient of the NaHy 0.1%, indicating, in those circumstances, the presence of salting-in effects. However, the opposite effect (salting-out) was verified with the increase in concentration of some salts, mainly for NH4SCN at 0.1 mol dm−3. In this particular salt, the cation is weakly hydrated and, consequently, its presence does not favor interactions between NaHy and water molecules, promoting, in those circumstances, less resistance to the movement of NaHy and thus to the increase of its diffusion (19%). These data, complemented by viscosity measurements, permit us to have a better understanding about the effect of these salts on the transport behaviour of NaHy.

Effect of Cobalt and Chromium Ions on the Chlorhexidine Digluconate as Seen by Intermolecular Diffusion

“…It should be noted that information on apparent diffusion coefficients of CHDG in a commercial mixture is of significant importance for understanding the behavior of this compound in practical dental applications. The reproducibility of these diffusion coefficients is similar to that observed for other systems, i.e., within ±2% [29,30]. * There is no CHDG in the flux and, consequently, the tracer diffusion coefficient is measured.…”

“…D 11 and D 22 are the main, whilst D 12 and D 21 are the crossdiffusion coefficients. For more details see, for example,[29].In the present work, pseudo-ternary dispersion profiles were prepared by injecting CoCl 2 (or CrCl 3 ) (component 1) + chlorhexidine digluconate (component 2) solution samples of compositionC 1 + ∆C 1 , C 2 intocarrier streams of composition C 2 , and by injecting CoCl 2 (or CrCl 3 ) (component 1) + chlorhexidine digluconate (component 2) solution samples of composition C 1 , C 2 + ∆C 2 into carrier streams of composition C 1 Coupled diffusion produces ternary dispersion profiles (Equations (…”

Dependence of Viscosity and Diffusion on β-Cyclodextrin and Chloroquine Diphosphate Interactions

“…From the fitting of the viscosity values of the CDP aqueous solutions (Table 2) to the Jones-Dole equation [28,29], we have obtained A = 1.75 dm 3/2 mol −1/2 and B = −10.6 dm 3 mol −1 . The small positive A value and the negative B value suggest that weak interactions between CDP-CDP entities are present, and CDP is a structure-breaking solute (chaotropic solute) [31].…”

Diffusion of Vanadium Ions in Artificial Saliva and Its Elimination from the Oral Cavity by Pharmacological Compounds Present in Mouthwashes

“…The Taylor dispersion method, which has been used to obtain mutual diffusion coefficients for a wide variety of aqueous binary and ternary systems, is described in great detail in some studies [ 47 , 48 ]. Basically, it consists of the dispersion of small amounts of solution injected into laminar carrier streams of water or solution of different compositions, flowing through a long capillary tube with a length and radius of 3.2799 (±0.0001) × 10 4 mm and 0.5570 (±0.00003) mm, respectively [ 49 , 50 ].…”