Sirolimus solubility in supercritical carbon dioxide: Measurement and modeling

The solubility of drugs in supercritical carbon dioxide is a key parameter in their processing. This study focuses on sirolimus, an immunosuppressive drug used in organ transplantation. Its solubility in supercritical carbon dioxide was measured using a static gravimetric method. Measurements were carried out at pressures ranging from 12.5 MPa to 25.0 MPa and temperatures from 313 K to 328 K. The findings revealed a molar fraction range of sirolimus between 1.20 × 10 −6 and 2.73 × 10 −6 and a direct solubility behavior in the investigated domain. The experimental data were correlated using several models. These included semi-empirical density-based models (Chrastil, Mendez-Santiago and Teja, Bartle et al ., Kumar and Johnston, Sparks et al ., and Sodeifian et al .), as well as equation of state-based models (Soave-Redlich-Kwong and Peng-Robinson). The results indicated that Sparks et al . and Soave-Redlich-Kwong showed the lowest average absolute relative deviation (AARD%) and the corrected correlation coefficient (R adj ) of 4.12 %, 0.978 and 05.18 %, 0.980 respectively. • Sirolimus solubility measured in supercritical carbon dioxide across varied pressures and temperatures. • Semi-empirical and equation of state models are used to correlate experimental solubility data. • Sparks et al , and Soave-Redlich-Kwong models show best data correlation performance.