Cecilia I.A.V. Santos

Diffusion Coefficients of Aqueous Solutions of Carbohydrates as Seen by Taylor Dispersion Technique at Physiological Temperature (37 °C)

Binary mutual diffusion coefficients have been measured for aqueous solutions of some carbohydrates (glucose, fructose, lactose, sucrose, α-cyclodextrin and β- cyclodextrin) at concentrations from 0.002 mol dm-3 to 0.010 mol dm-3. The concentration dependence of the diffusion coefficients at physiological temperature, 37 °C, is discussed on the basis of their structures.

Isothermal molecular diffusion in mixtures containing toluene, cyclohexane and methanol

Abstract.The Taylor dispersion technique has been used for measuring ternary mutual diffusion coefficients for mixtures of cyclohexane-toluene-methanol, corresponding to the mixtures under study on the International Space Station (ISS) within the scope of the project DCMIX2 (second series of the experiment Diffusion Coefficients in Mixtures). Five ternary systems with different composition of cyclohexane-toluene-methanol were investigated in order to accurately obtain the mass diffusion coefficients, contributing to a better understanding of the isothermal molecular diffusion in conjunction with the coupled flows of solutes occurring in such fluid systems. Current standardized protocols for carrying out an experience are also examined to understand if the experimental conditions may be ill conditioning the final results.Graphical abstract

Effect of HP-β-cyclodextrin in the diffusion behaviour of hydrocortisone in aqueous solutions at T=298.15 K.

Binary (D) and ternary (D(11), D(22), D(12) and D(21)) mutual diffusion coefficients determined by the Taylor dispersion method are reported for two aqueous systems, pure hydrocortisone (HC/H(2)O) and HC plus HP-β-cyclodextrin (HC/HP-βCD/H(2)O), at T=298.15 K. From these data, some thermodynamic information as well as conclusions about the influence of that carbohydrate in the diffusion of this drug are given.

Chapter 6:Diffusion of Caffeine in Different Aqueous Media at Physiological Temperature

It is known that the solubility of a drug is one of the main factors for its effectiveness. In fact, its absorption from the gastrointestinal tract to pass into the circulatory system by passive diffusion depends on its solubility in water. Moreover, the passage of a drug through a membrane, and its...