Preparation of floating polymer-valsartan delivery systems using supercritical CO2

This study investigates pharmaceutical polymers (Soluplus®, HPMCAS, and Eudragit® E100) and supercritical CO2-assisted process for preparation of floating valsartan delivery systems. Tested process (at pressure of 30 MPa and temperature of 100 °C during 2 h) enabled preparation of stable porous valsartan formulations which was confirmed with FESEM and mercury intrusion porosimetry analysis. The bulk density of obtained formulations was lower than 550 kg/m3. FTIR, DSC, and PXRD analysis indicated that there was no chemical interaction between the drug and polymers and that amorphous solid dispersions were obtained. Formulations with Soluplus® and HPMCAS retained its buoyancy in 0.1 M HCl for longer than 24 h, while formulation with Eudragit® E100 retained its buoyancy up to 2 h. Controlled valsartan release was influenced by solubility of polymers in the tested release medium, which was confirmed by UV/VIS spectroscopy. The obtained results provided framework for further development of floating drug delivery system using an environmental friendly process.