Modeling the solubility of non-steroidal anti-inflammatory drugs (ibuprofen and ketoprofen) in supercritical CO2 using PC-SAFT

A method to estimate the solubilities of two non-steroidal anti-inflammatory drugs (NSAIDs), ibuprofen and ketoprofen, as active pharmaceutical ingredients (APIs) in supercritical CO2 (scCO(2)), was examined using perturbed-chain statistical associating fluid theory (PC-SAFT), which is more predictive than conventional methods that use cubic-type equations of state and semi-empirical correlation models. The values of the three PCSAFT pure-component parameters of the API were adjusted to the solubility in organic solvents and determined. These parameters were then applied to estimate the solubility of the API in scCO(2). The PC-SAFT solubility calculations almost reproduced the experimental values over a wide pressure range, even when kij (the binary interaction parameter) was set to zero. Furthermore, the isobaric solubility of scCO(2) was successfully described by PC-SAFT using the generalized kij.