Taylor dispersion technique as a tool for measuring multicomponent diffusion in drug delivery systems at physiological temperature

Highlights: • Diffusion of the systems containing potassium chloride, xantine and cyclodextrin. • Influence of potassium chloride in the diffusion of theophylline. • Coupled diffusion as indicated by cross-diffusion coefficients. - Abstract: The Taylor dispersion technique was used to measure quaternary diffusion coefficients, ¹²³D₁₁, ¹²³D₂₂, ¹²³D₃₃, ¹²³D₁₂, ¹²³D₁₃, ¹²³D₂₁, ¹²³D₂₃, ¹²³D₃₁, and ¹²³D₃₂, in aqueous solutions of 2-hydroxypropyl-β-cyclodextrin (HP-βCD) + KCl + caffeine (CAF) + water, and 2-hydroxypropyl-β-cyclodextrin (HP-βCD) + KCl + theophylline (THP) + water at T = 310.15 K at different carrier concentrations of 0.002, 0.005 and 0.010 mol · dm⁻³, for each solute. The behaviour diffusion of these multicomponent systems and the coupled flows occurring in the solution can be explained on the basis of salting-out effects, as well as the possible interactions between both (cyclodextrin + xantine) or (cyclodextrin + metal ion) interactions, lead us in this way to obtain a better understanding of the structure of these systems