Solubility of sulphadiazine in (acetonitrile + water) mixtures: measurement, correlation, thermodynamics and preferential solvation

ABSTRACT

The equilibrium solubility at temperatures from (293.15 to 313.15) K, dissolution thermodynamics and preferential solvation of sulphadiazine (SD) in {acetonitrile (ACN) (1) + water (2)} mixtures is reported. Mole fraction solubility of SD (x₃) increases when temperature arises and also increases with the ACN proportion increasing. It varies from 4.81 × 10^–6 in neat water to 6.02 × 10^–4 in neat ACN at 298.15 K. Solubility behaviour was adequately correlated by Jouyban-Acree, modified Wilson and non-linear (proposed by Machatha et al.) models and the obtained mean percentage deviations (MPD) are 4.1%, 2.3% and 2.3%, respectively. The comparison of the MPD shows that the prediction using Jouyban-Acree model is more accurate than Jouyban-Acree-Abraham equation for solubility prediction of SD in {ACN (1) + water (2)}. From the variation of solubility with temperature the apparent thermodynamic analysis of dissolution was performed in all the mixtures and neat solvents. Based on the inverse Kirkwood-Buff integrals preferential solvation parameters were calculated. SD is preferentially solvated by water in water-rich mixtures (0.00 < x₁ < 0.26) but preferentially solvated by ACN in the interval (0.26 < x₁ < 0.65). In ACN-rich mixtures the behaviour is not well defined.

KEYWORDS:

• Sulphadiazine
• {acetonitrile (1) + water (2)} mixtures
• solubility
• Jouyban-Acree model
• preferential solvation
• Inverse Kirkwood-Buff integrals (IKBI)

Acknowledgments

We thank the National Directorate of Research and National Committee for Research Development of the Universidad Cooperativa de Colombia, for the financial support of the Project “Estudio termodinámico de la solubilidad de algunas sulfonamidas en mezclas disolventes ciclohexano + etanol a diferentes temperaturas” with code INV1863. Further, we thank the Universidad Cooperativa de Colombia, sede Neiva, for facilitating the laboratories and equipment used.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

We thank the National Directorate of Research and National Committee for Research Development of the Universidad Cooperativa de Colombia.