Acetylated cashew gum-based nanoparticles for transdermal delivery of diclofenac diethyl amine

•Polymer nanoparticles were prepared using the modified polysaccharide from cashew gum.•The nanoparticles were characterized using spectrophotometry in the region near ultraviolet and visible and dynamic light scattering.•NPs were loaded with diclofenac diethylammonium and the efficiency of incorporation of the drug and in vitro permeation assay were evaluated. Nanoprecipitation and dialysis methods were employed to obtain nanoparticles (NPs) of acetylated cashew gum (ACG). NPs synthesized by dialysis showed greater average size compared to those synthesized by nanoprecipitation, but they presented improved stability and yield. NPs were loaded with diclofenac diethylamine and the efficiency of the drug incorporation was over 60% for both methods, for an ACG:NP a weight ratio of 10:1. The cytotoxicity assay demonstrated that the NPs had no significant effect on the cell viability, verifying their biocompatibility. The release profile for the diclofenac diethylamine associated with the ACG-NPs showed a more controlled release compared to the free drug and a Fickian diffusion mechanism was observed. Transdermal permeation reached 90% penetration of the drug.