Journal of Physical Chemistry B, Vol.120, No.14, 3540-3550, 2016
Computer Simulation Studies of the Mechanism of Hydrotrope-Assisted Solubilization of a Sparingly Soluble Drug Molecule
The effect of hydrotrope sodium cumene sulfonate (SCS) on the solubility of a sparingly water-soluble drug, griseofulvin, is studied by employing classical molecular dynamics simulation technique. We mainly focus on the underlying mechanism by which SCS enhances the solubility of a sparingly soluble or insoluble solute in water. The main observations are the following: (a) The self-aggregation of SCS molecules (through its hydrophobic tail) above the minimum hydrotrope concentration (MHC) causes the formation of micellar-like frameworks. Interestingly, though the drug griseofulvin possesses both polar and nonpolar groups, it prefers to get encapsulated inside the hydrophobic core of SCS aggregates. The decomposition of total SCS drug interaction energy into van der Waals and electrostatic components suggests that the former plays a major role in this interaction. (b) The calculated Flory-Huggins interaction parameter values give a strong indication of the mixing ability of hydrotrope SCS and griseofulvin drug molecules. (c) As expected, we do not observe any strong effect of SCS aggregates on SCS-water and water-water average hydrogen-bond number, but it affects water drug griseofulvin average hydrogen-bond number. With the help of these observations we try to elucidate the hydrotropic action of hydrotrope SCS on the solubility of drug griseofulvin.