Drug loading of bioresorbable suture threads by supercritical CO2 impregnation: a proof of concept for industrial scale-up

Supercritical CO2 (scCO2) impregnation emerged as a suitable technique to load thermosensitive drugs in polymeric devices thanks to mild process temperatures, the absence of toxic solvents and the easy removal of residual solvent through depressurization. This technique has been successfully tested at lab scale but few attempts to scale-up the process are reported. This work aims at filling this gap by performing a scCO2 impregnation at pilot scale of bioresorbable suture threads with ketoprofen. The process led to low drug loading values (0.2 - 0.8%) and to a very fast eluting rate, suggesting that they can be suitable when an immediate burst release is needed. Experiments were complemented by a multiscale mathematical modeling to better rationalize the outcomes. This work constitutes a proof of concept for a possible strategy to perform the scale-up of scCO2assisted drug loading and highlighted some aspects to be addressed for future developments.