Floating solid cellulose nanofibre nanofoams for sustained release of the poorly soluble model drug furosemide.

Objectives: This study aimed to prepare a furosemide-loaded sustained release cellulose nanofibre (CNF)-based nanofoams with buoyancy.

Methods: Dry foams consisting of CNF and the model drug furosemide at concentrations of 21% and 50% (w/w) have been prepared by simply foaming a CNF-drug suspension followed by drying. The resulting foams were characterized towards their morphology, solid state properties and dissolution kinetics.

Key Findings: Solid state analysis of the resulting drug-loaded foams revealed that the drug was present as an amorphous sodium furosemide salt and in form of furosemide form I crystals embedded in the CNF foam cell walls. The foams could easily be shaped and were flexible, and during the drug release study, the foam pieces remained intact and were floating on the surface due to their positive buoyancy. Both foams showed a sustained furosemide release compared to a marketed tablet. It was found that the extent of sustained release from both foams was dependent on the drug loading, the dimension of the foam piece, as well as the solid state of the drug.

Conclusions: Furosemide-loaded CNF-based foams with sustained release and buoyancy have been successfully prepared in a simple casting and drying procedure.