Self-assembled nanoparticles based on amphiphilic chitosan derivative and arginine for oral curcumin delivery

Curcumin (Cur) is a striking anticancer agent, but its low aqueous solubility, poor absorption, hasty metabolism, and elimination limit its oral bioavailability and consequently hinder its development as a drug. To redress these limitations, amphiphilic chitosan (CS) conjugate with improved mucoadhesion and solubility over a wider pH range was developed by modification with hydrophobic acrylonitrile (AN) and hydrophilic arginine (Arg); the synthesized conjugate (AN-CS-Arg), which was well characterized by Fourier transform infrared and ¹H nuclear magnetic resonance spectroscopy. Results of critical aggregation concentration revealed that the AN-CS-Arg conjugate had low critical aggregation concentration and was prone to form self-assembled nanoparticles (NPs) in aqueous medium. Cur-encapsulated AN-CS-Arg NPs (AN-CS-Arg/Cur NPs) were developed by a simple sonication method and characterized for the physicochemical parameters such as zeta potential, particle size, and drug encapsulation. The results showed that zeta potential of the prepared NPs was 40.1±2.81 mV and the average size was ~218 nm. A considerable improvement in the aqueous solubility of Cur was observed after encapsulation into AN-CS-Arg/Cur NPs. With the increase in Cur concentration, loading efficiency increased but encapsulation efficiency decreased. The in vitro release profile exhibited sustained release pattern from the AN-CS-Arg/Cur NPs in typical biological buffers. The ex vivo mucoadhesion study revealed that AN-CS-Arg/Cur NPs had greater mucoadhesion than the control CS NPs. Compared with free Cur solution, AN-CS-Arg/Cur NPs showed stronger dose-dependent cytotoxicity against HT-29 cells. In addition, it was observed that cell uptake of AN-CS-Arg/Cur NPs was much higher compared with free Cur. Furthermore, the in vivo pharmacokinetic results in rats demonstrated that the AN-CS-Arg/Cur NPs could remarkably improve the oral bioavailability of Cur. Therefore, the developed AN-CS-Arg/Cur NPs might be a promising nano-candidate for oral delivery of Cur.