Effect of β-alanine and the solvent composition on the solubility of solvate of calcium d-pantothenate containing four molecules of methanol and one molecule of water (D-PC·4MeOH·1H2O)

The solubility of calcium d-pantothenate in (water + methanol) mixtures and the effect of β-alanine on the solubility of calcium d-pantothenate in a constant mole ratio of methanol and water was measured from 263.15 K to 303.15 K by the HPLC analysis method (P = 0.1 MPa). The solubility of calcium d-pantothenate increased with increasing temperature in all the mixtures at constant composition. Besides, it also increased with mole fraction of water in (water + methanol) mixtures at a constant temperature. Additionally, the solubility of calcium d-pantothenate was enhanced by β-alanine at a given temperature. The experimental solubility in (water + methanol) mixtures was correlated by the modified Apelblat equation, the ternary NRTL equation and Solubility-Polarity Model. The Apelblat equation, the quaternary NRTL equation and the Cohn equation were adopted to correlate the experimental solubility in the (water + methanol + β-alanine) mixtures. Worthwhile, the quaternary NRTL equation was first applied to correlating the quaternary solid-liquid equilibrium. It turned out that all the selected models give good performance on solubility prediction.