Solubility Measurement and Thermodynamic Model Correlation and Evaluation of Macitentan Form I in Five Pure Solvents (Methanol, Ethanol, n-Propanol, Isopropanol, and N,N-Dimethylformamide) and Their Solvent Mixtures

In this work, the solubility of macitentan form I in four mixtures (N,N-dimethylformamide, DMF + methanol, ethanol, n-propanol, and isopropanol) at T = 273.15-313.15 K and at atmospheric pressure was studied. At all studied temperatures, the solubility increased monotonically with the increase in the mass fraction of DMF; the largest mole solubility was 1.393 x 10(-1) at 313.15 K in pure DMF. The minimum value was observed in pure alcohols. In mixtures of DMF + methanol, the values varied from 6.094 x 10(-4) to 1.393 x 10(-1) at 313.15 K, an increase of 228.6-fold and 278.8-fold, 319.3-fold, and 529.1-fold for mixtures of DMF + ethanol, DMF + n-propanol, and DMF + isopropanol, respectively. The values of the relative average deviation (RAD) in binary mixtures of DMF + methanol, DMF + ethanol, DMF + n-propanol, and DMF + isopropanol for the Jouyban-Acree model were 0.33, 0.23, 0.60, and 0.29%, respectively. However, for the CNIBS/R-K model, the maximum data of RAD was 3.73% at 273.15 K in the mixture of DMF + methanol. The data of the residual sum of squares (RSS) for the Jouyban-Acree model and the CNIBS/R-K model were 9.20 x 10(-7) and 1.77 x 10(-5), respectively. The Jouyban-Acree model provided the best correlation results due to the lowest RAD and RSS. The result of the analysis suggests that the Jouyban-Acree model is the most suitable to describe the dissolution behavior of macitentan in four binary mixtures.