The low solubility of
curcumin is caused by its crystal nature and high hydrophobicity. When exists in crystal phase, curcumin forms both inter and intramolecular hydrogen bonding which inhibits curcumin dissolving in the aqueous solution. However, when in the amorphous state, curcumin could form certain interaction with some polymers (Li, Lee, et al., 2015; Vukicevic & Tønnesen, 2015). Moreover, in the composite matrix, polymer may prevent the growth of curcumin crystal and maintain the amorphous state as well as higher water solubility. Compared with the reported solubility value, cur@star 3 wt% formulation increased the solubility of curcumin by at least 715 fold