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

•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.

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.