Unraveling the binding and micellization behavior of dioctylsulfosuccinate Sodium Salt with vitamin B1 and B6: A physiochemical and computational study

Abstract

The outcomes of drug delivery rely on the route of administration which further depends on the understanding of interactional or partitioning mechanism of drugs within the self assembled structures. Thus, identification of various interactions in such systems is of utmost importance. Herein, the partitioning of vitamins: B1 (thiamine hydrochloride; THC) and B6 (Pyridoxine hydrochloride; PyH) in dioctyl sulfosuccinate sodium salt (AOT) have been addressed by employing experimental and computational techniques. The values of partial molar volumes (ΔtrV2,фo) and partial molar isentropic compressions ΔtrKS,2,фo of transfer for PyH have been calculated from density and sound velocity measurements which suggest the presence of hydrophilic interactions between AOT and PyH. The obtained results were further supported by Density Functional Theory Calculations which suggest that hydrogen bonding plays important role in PyH/AOT binding. The binding constants along with thermodynamic parameters at different temperatures have been calculated using calorimetric measurements. In case of THC/AOT the negative values of ΔrS are overcome by more negative values of ΔrH, making the overall process favorable. In case of PyH, two set of binding sites with stronger affinity for second site have been observed along with favorable entropy. Calorimetric and surface tension measurements were used to study the impact of PyH/THC on the Critical micelle concentration of AOT. Spectroscopic and Dynamic light scattering studied have been used as complementary techniques that also confirmed the partitioning of vitamins in AOT micelles.