Study of solute-solvent intermolecular interactions and preferential solvation for mevastatin dissolution in pure and mixed binary solvents

Abstract

The solute-solvent and solvent-solvent interactions between mevastatin and different solvents were studied. In pure solvent, the largest solubility was found in 2-butanone (2.592×10−2) and minimum in cyclohexane (5.068×10−5) at 318.15 K. The non-specific and hydrogen bonding interactions including the dipolarity/polarizability (π*), Hildebrand solubility parameter (δH), hydrogen bond acidity (α) and hydrogen bond basicity (β) were analyzed. In mixture of (ethyl acetate + ethanol), the maximum solubility (2.144×10−2) is observed in 80%: 20% w/w of ethyl acetate: ethanol. Almost the same interaction energy and equilibrium mixing energy between solute and solvent promote the occurrence of co-solvency phenomenon. Moreover, according to the preferential solvation results, it is conjecturable that in intermediate composition mixtures and ethyl acetate-rich mixtures, mevastatin molecules are acting mainly as Lewis acid and Lewis base, respectively. Meanwhile, two thermodynamic models including modified Apelblat equation and Jouyban-Acree model are suitable to evaluate the dissolution profile, and the maximum value of relative average deviation is no >5%. The apparent thermodynamic properties of dissolution process in all investigated solvents are calculated which suggest that dissolution process is an endothermic process.