Two-step method for encapsulation of oregano essential oil in chitosan nanoparticles: Preparation, characterization and in vitro release study

► Oregano essential oil was encapsulated in chitosan nanoparticles. ► Oil presence in nanoparticles was corroborated by FTIR, TGA and XRD techniques. ► Particles had spherical shape and size range about 40-80 nm. ► The release profile of the OEO showed burst effect followed by slow release.