Solubilisation of dexamethasone: experimental data, co-solvency and Polarised Continuum Modelling

Experimental solubility of dexamethasone was obtained in binary aqueous mixtures of ethanol, methanol and acetonitrile at 298.2 K. The effects of micellization and pH were also investigated on the solubility of the drug. Experimental solubility data in the binary solvent mixtures were correlated by three co-solvency models, i.e. Yalkowsky, CNIBS/R-K, and the modified Wilson model. A new principle has also been investigated with the purpose of modelling drug solubility in the binary solvent mixtures using Polarised Continuum Model (PCM) by using the hybrid functional B3LYP method and 6–311++G** basis set. By matching experimental data with PCM modelling, we investigated the outcome of drug solubility in various mass fractions of binary solvent mixtures. Here we report the solute-solvent interaction energy as free energy of solvation (∆Gsol), total electrostatic energy, dipole moment, total Gibbs-free energy and dielectric constant (ε) of dexamethasone in various mass fractions of ethanol + water mixtures.