Experimental and thermodynamic modeling of sumatriptan solubility in supercritical carbon dioxide for green pharmaceutical applications

This study examined the solubility of sumatriptan when dissolved in supercritical carbon dioxide. The temperature of the system was varied between 308 and 338 K, and the pressure was ranged between 10 and 30 MPa. The experimental mole fraction and the solubility ranged from 4.30 × 10^-6 to 5.26 × 10^-5 and from 0.010 to 0.278 g/l respectively with a cross over point of 15 MPa. A total of four semi-empirical models (Chrastil, Bartle et al., K-J, and MST) were evaluated for their potential in facilitating both the correlation and the self-consistency of the data. The K-J method yielded the best outcome, with an AARD of 8.21% and a R_adj of 0.991. These models also helped estimate thermal enthalpies ([Formula: see text] = 40.96 kJ mol^-1, [Formula: see text] = 59.83 kJ mol^-1, and [Formula: see text] = - 18.87 kJ mol^-1). Thermodynamic modeling using the PC-SAFT, Peng-Robinson and Soave-Redlich-Kwong combined with mixing rules showed that the PC-SAFT offered better accuracy (AARD = 11.75%, R_adj = 0.988). These findings provide essential experimental data and validated predictive models that are critical for designing eco-friendly supercritical fluid processes, such as the supercritical anti-solvent.