Molecular Mechanisms Involved in Supersaturation of Emodin Ternary Solid Dispersions Based on Bonding Agents

Abstract

The use of solid dispersions (SDs) is an established method for improving the dissolution rate of poorly water-soluble drugs. However, there have been few studies on the molecular mechanisms contributing to SD supersaturation. Emodin ternary SDs (TSDs) were prepared by hot melt extrusion (HME) using Kollidon® VA64 as the polymer carrier and nicotinamide as the bonding agent. Molecular docking and solubility tests were used to assist screening of polymer carriers, and in vitro dissolution and dissociation constant data were used to optimize the formulation. A variety of analytical methods and molecular dynamics simulations were used to investigate the mechanism of SD supersaturation at the molecular level. The results showed that molecular migration, intermolecular interactions, drug crystal transformation and dissociation constant were particularly important factors in SD supersaturation. This study proposes a new strategy to improve solubility of poorly water-soluble drugs and explore the molecular mechanisms of TSD supersaturation, which could provide a basis for the rational selection of excipients for pharmaceutical preparations.

Keywords: Bonding agent; Intermolecular interaction; Molecular migration; Supersaturation; Ternary solid dispersion.