Synthesis and characterization of non-toxic and thermo-sensitive poly(N-isopropylacrylamide)-grafted cashew gum nanoparticles as a potential epirubicin delivery matrix

•Cashew gum grafted N-isopropylacrylamide was successfully synthesized.•The graft copolymer demonstrated thermal responsiveness.•The nanoparticles showed no cytotoxic activity against the Caco-2 and HT29-MTX.•Copolymer shows good epirubicin association efficiency.

Cashew gum (CG) was grafted with N-isopropylacrylamide (NIPA) by radical polymerization to originate a stimuli-sensitive copolymer for drug delivery purposes. NMR and IR spectroscopy confirmed the insertion of NIPA onto the cashew gum chains. The graft copolymer (CG:NIPA) demonstrated thermal responsiveness. The critical aggregation concentration of the copolymers at 25 °C was higher than at 50 °C. At temperatures lower than the LCST, the nanoparticle size ranged from 12 to 21 nm, depending on the CG:NIPA ratio, but above the LCST the particles aggregated, increasing the particle size. Regarding the potential for future oral application, the nanoparticles showed no cytotoxic activity against the Caco-2 and HT29-MTX intestine cell lines. Epirubicin was encapsulated into nanoparticles of CG-NIPA (1:1), resulting in a 64% association efficiency and 22% loading capacity. Thus, the CG:NIPA graft copolymer demonstrates good potential for used in controlled drug delivery systems.