Insert Figure In Figure , the Higuchi kinetic model closely fits the two samples studied, confirming that the release occurs predominantly by diffusion in the second part and in the first part depending on the solubility, which is mediated by particle size. This result is consistent with the release of artemisinin from Cit-Hap NRs at pH = 7.4 . The fit is more accurate for H9-EN, confirming the controlled release.