Solubility measurement of Triamcinolone acetonide (steroid medication) in supercritical CO2: Experimental and thermodynamic modeling

Triamcinolone Acetonide (TA, Steroid Medication) solubility in supercritical carbon dioxide (ScCO2) was determined for the first time at 308, 318, 328, and 338 K and pressures of 120–270 bar. The results showed that mole fractions of TA dissolved in ScCO2 ranged from 6.90 × 10−6 to 2.13 × 10−4, and the solubility ranged from 0.052 to 1.650 g/L. Four different types of models were examined; (1) seven known density-based models, with 3–6 adjustable parameters, namely Sung-Shim, Chrastil, Kumar–J and Bian et al., MST, Bartle, and Sodeifian; (2) Equation of state (EoS) based model, specifically Peng-Robinson (PR) EoS, coupled with two conventional types of van der Waals mixing rules; (3) a Solid-Liquid Equilibrium (SLE) based model, developed by Soedifian et al.,; (4) several machine learning-based models, namely Ridge Regression, Huber Regression, Random Forest, and Gaussian Process. Based on the results, all applied models accurately described TA solubility in ScCO2, although Sodeifian et al. model led to superior results based on AARD% and Kumar–Johnston model based on Bayesian Information Criterion (BIC). Finally, thermodynamic enthalpies of TA were estimated for the first time.