Dissolution enhancement of quercetin through nanofabrication, complexation, and solid dispersion.

The main aim of this study was to enhance the dissolution rate of a poorly water-soluble antioxidant drug, quercetin, by fabricating its nanoparticles, complexes and solid dispersions using evaporative precipitation of nanosuspension (EPN). We studied the influence of the type of antisolvent, drug concentration and solvent to antisolvent ratio on the quercetin particles formed during EPN. With water as antisolvent, the particles were big, irregular and flake type but with benzene or hexane as antisolvent, the particles were smaller and needle type. Smallest particles of 220 nm diameter were achieved with hexane as antisolvent, lowest drug concentration and highest solvent to antisolvent ratio. The relative dissolution values showed that the dissolution rate of the EPN prepared quercetin nanoparticles was much higher than that of the raw drug. Quercetin formed inclusion complexes with β-cyclodextrin, and solid dispersions with polyvinylpyrrolidone and pluronic F127, where quercetin was present in an amorphous form and/or was dispersed at a molecular level. The dissolution rate of quercetin in its complexes and solid dispersions improved significantly from the raw quercetin as indicated by the percent dissolution efficiency. It was interesting to note that at lower carrier concentration, the solid dispersions of quercetin with polyvinylpyrrolidone and pluronic F127 presented better dissolution than its complex with β-cyclodextrin but at higher carrier concentration, there was no significant difference in the dissolution behavior of the three formulations. Using Korsmeyer-Peppas model, diffusion was found to be the main release mechanism.