Resveratrol (RES) is natural polyphenol with a strong biological activity, but its disadvantages, such as poor water solubility, susceptibility to oxidative decomposition and rapid metabolism in the body, which substantially restricts in vivo bioavailability, need to be resolved. This study used carboxymethyl chitosan (CMCS) as a drug carrier and utilized emulsion cross-linking to prepare RES-loaded CMCS nanoparticles (RES-CMCSNPs). A single-factor experiment was performed to optimize the preparation of these particles; in vitro and in vivo characteristics were evaluated. Spherical RES-CMCSNPs were prepared under optimal conditions, in which average particle size, potential, drug loading and encapsulation efficiency were (155.3 ± 15.2) nm, (-10.28 ± 6.4) mV, (5.1 ± 0.8)% and (44.5 ± 2.2)%, respectively. FTIR, DSC and XRD showed that RES molecules were wrapped in the nanoparticles. In vitro DPPH radical scavenging abilities showed RES-CMCSNPs were better than RES raw powder. The nanoparticles improved the solubility of RES, thereby greatly improving the antioxidant activity of the drug. In vitro release experiments of RES and RES-CMCSNPs by simulating the human gastrointestinal tract were performed, in which RES-CMCSNPs rendered better releasing effects than raw RES. Raw RES and RES-CMCSNPs results were in line with those obtained for the single-chamber model for pharmacokinetic studies in rats. Compared with the bulk drugs, the RES-CMCSNPs exhibited increased in vivo absorption, prolonged duration of action and increased relative bioavailability by 3.516 times more than those of the raw RES. In addition, the residual chloroform is less than the ICH limit for class 2 solvents.
Keywords: Antioxidant; bioavailability; carboxymethyl chitosan; nanoparticles; resveratrol.