Solubility of codeine phosphate in ethylene glycol + N-methyl-2-pyrrolidone mixtures at different temperatures

ABSTRACT

The primary objective of the present study is to systematically investigate the solubility data and thermodynamic properties associated with codeine phosphate within mixtures comprising ethylene glycol (EG) and N-methyl-2-pyrrolidone (NMP) under atmospheric pressure conditions within the temperature range of 293.2–313.2 K. The analysis reveals a discernible positive correlation with both temperature and the ratio of EG. Mathematical models are employed for the purpose of correlating the obtained data, and the reliability of these models is rigorously assessed through the computation of mean relative deviations for back-calculated values. Additionally, the density values of codeine phosphate saturated mixtures are meticulously measured and subsequently correlated utilising the Jouyban-Acree model. Furthermore, the apparent thermodynamic properties governing the solubilisation process of codeine phosphate, including standard enthalpy, entropy and Gibbs free energy, are computed through the application of Gibbs and van’t Hoff equations, and the obtained results are comprehensively documented.

KEYWORDS:

• Codeine phosphate
• solubility
• N-methyl-2-pyrrolidone
• ethylene glycol
• binary solvent mixture
• cosolvency models

Acknowledgments

The research protocol was approved and supported under grant number 74385, Tabriz University of Medical Sciences, Tabriz, Iran.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Tabriz University of Medical Sciences [74385].