Preparation and in vitro and in vivo evaluation of oral curcumin nanocrystalline capsules

The poorly water-soluble drug curcumin was prepared into oral nanocrystalline solid preparation by nanocrystal technology to improve the solubility, dissolution rate, and bioavailability. Curcumin nanocrystals were prepared by media grinding technology, and two types of stable curcumin nanocrystal suspension formulations were developed. The stabilizers in the two formulations were polyvinylpyrrolidone (PVP K30)/sodium lauryl sulfate (SDS)(1∶1) and Tween 80, respectively. The prepared curcumin nanocrystal suspension was loaded onto microcrystalline cellulose pellets through fluidized bed coating technology, and the nanocrystalline capsules were obtained after filling. The results of nanocrystal redispersion stability and scanning electron microscope (SEM) showed that the morphology of drug-loaded pellets was uniform when PVP K30 and SDS were used as stabilizers, and the diameter of nanocrystals before and after redispersion was about 200 nm, which was determined as the optimal formulation. In vitro dissolution study showed that curcumin nanocrystals at the size of 200 nm exhibited significantly promoted dissolution. The results of X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) showed that the curcumin crystalline partly turned amorphous during the preparation of nanocrystals.Pharmacokinetic studies in rats showed that the bioavailability of curcumin nanocrystals was 9.3 times higher than that of the bulk drug. The curcumin nanocrystalline capsules developed in this research can significantly improve the dissolution rate and bioavailability, which is of great significance in improving the poor solubility of drugs, and is expected to become a new dosage form for clinical treatment.