Experimental determination and modelling of the co-solvent and antisolvent behaviour of binary systems on the dissolution of pharma drug; L-aspartic acid and thermodynamic correlations

Solid-liquid equilibrium (SLE) data and thermodynamic properties play an important role to understand the crystallization phenomenon as it became an important step for purification and separation to get a required specific product. In this study, solubility of L-aspartic acid (L-ASP) in different binary mixtures (formic acid/trimethylamine(TMA)/methanol/iso-propylalcohol(IPA) + water) were carried out at temperatures from 283.15 to 328.15 K. The experimental data was generated using the gravimetric and titrimetric method. For a binary system, the solubility of L-ASP increased with increasing temperature. The effect of solvent on mole fraction solubility of L-ASP decreased with increasing methanol/IPA mole fraction in mixture, whereas solubility increased with increased formic acid/TMA fractions in mixture. The order of solubility for binary solvents systems as follows: TMA + water > formic acid + water > methanol + water > IPA + water. Different thermodynamic models like Apelblat equation, Apelblat-Jouyban-Acree model, NRTL model, and general single model were applied to correlate the experimental data. It was found that Apelblat equation and general single model was the best-fit for correlating solubility of L-ASP in binary mixtures with average relative deviation (ARD) less than 2% and root mean square deviation (RMSD) are below 5.3E-04. It can also be concluded that formic acid and TMA act as co-solvent in dissolution of L-ASP in their respective binaries, wheras methanol and IPA exhibited anti-solvent effect in the aqueous solution. The generated SLE data would be helpful in technological research for production of drugs in purification and separation process. (C) 2020 Elsevier B.V. All rights reserved.