Solubility and thermodynamic functions of deferasirox in different solvents

Abstract

The total solubility of deferasirox was determined in pure methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, acetonitrile, 1,4 dioxane and DMSO, at 25.0°C as well as in aqueous solutions of methanol from 20.0 to 80.0% (v/v) methanol in a temperature range of 25.0–40.0°C and constant ionic strength (0.1mol·dm−3 NaCl). The UV–Vis spectrophotometric results have shown that by increasing both temperature and methanol mole fraction as well as decreasing the dielectric constant of the medium causes an increase in solubility of the drug with an exception in DMSO. The solubility data were correlated by the Apelblat equation and the thermodynamic functions of dissolution were calculated at the mean temperature (Tm) at different mole fractions of methanol using the modified Van't Hoff method. Considering the dielectric constant and the polarity/polarizability parameter of the solvents used, the relation between the nature of solvents, solubility, ΔH°, and ΔS° of dissolution were determined and discussed.