Production of Luteolin/Biopolymer Microspheres by Supercritical Assisted Atomization

Supercritical assisted atomization (SAA) was used to produce coprecipitated submicroparticles of luteolin (LUT)/poly­(vinylpyrrolidone) (PVP) for pharmaceutical applications. LUT has antioxidant, antiinflammatory, and antitumoral properties but is poorly water-soluble, whereas PVP is highly water-soluble. This polymer can be used to protect the active molecule and to improve its bioavailability. Different LUT/PVP weight ratios were selected ranging between 1:4 and 1:8. SAA produced partly collapsed spherical particles with controlled particle size and mean diameters ranging between 0.22 and 0.33 μm. UV–vis analyses revealed very high loading efficiency of LUT in SAA particles (99–100%). The powders are amorphous, whereas the untreated material shows crystalline patterns. Fourier transform infrared revealed that hydrogen bonds were created between the drug and polymer. Drug-release analysis indicated that the supercritical processing was successful: the LUT dissolution rate in a phosphate-buffered saline solution was up to 9 times faster compared to that of an unprocessed drug.