pH-driven self-assembly of alcohol-free curcumin-loaded propylene glycol alginate nanoparticles

The purpose of this paper was to explore the application of propylene glycol alginate (PGA) alone in alcohol-free curcumin-loaded nanoparticles (PGA/Cur) prepared by a pH-driven method to solve the curcumin shortcomings of low water solubility, stability and bioavailability. One of the bright spots of PGA/Cur was its extremely high loading capacity. PGA/Cur formed a spherical structure mainly by hydrophobic interaction and hydrogen bonding, making curcumin amorphous. PGA/Cur exhibited stability at pH 4.0-8.0 due to its high surface charges. PGA/Cur still showed a unimodal size distribution even under 3000 mM ionic strength. Heating caused uneven size distribution, but the smaller size still presented its thermostability. PGA/Cur exhibited good physical stability and slowed down the curcumin degradation with t_1/2 of 37.47 days during storage. PGA/Cur could maintain structural integrity in gastric acid and released curcumin in the intestine, thus improving the bioaccessibility of curcumin. Additionally, PGA/Cur displayed the solubilization after lyophilization.