Supercritical Assisted Atomization for the production of curcumin-biopolymer microspheres

Supercritical Assisted Atomization (SAA) has been applied to the formation of microspheres curcumin (CUR)-polyvinylpyrrolidone (PVP) to be used for biomedical applications. CUR has antioxidant, anti-inflammatory and antitumoral properties and is poorly water soluble; whereas, PVP is highly water soluble. The aim was to entrap CUR in form of nanoparticles in a polymeric hydrosoluble carrier, to protect the active principle and to enhance its bioavailability. Four CUR/PVP weight ratios were selected: 1/2, 1/4, 1/6 and 1/8 and processed by SAA at 80 °C and 99 bar in the saturator and 80 °C and 1.50 bar in the precipitator. Spherical particles of CUR/PVP were obtained in all cases, characterized by a mean size, calculated on particle number %, smaller than 400 nm and a D90 lower than 1 μm. X-ray, DSC, FTIR analyses showed that the microspheres were amorphous and that the drug was intimately mixed with the polymer. UVâvis spectrometric analyses confirmed an high loading efficiency of the active principles microspheres, ranging between 94 and 100%. Dissolution tests in aqueous environment at different pH values were performed to measure the improvement of the dissolution rate. It resulted up to 4.5 times faster with respect to the physical mixture for the most favorable 1/8 ratio, with a complete CUR dissolution time of 5.5 h at pH 6.5