Influence of Surface Modification and the pH on the Release Mechanisms and Kinetics of Erlotinib from Antibody-Functionalized Chitosan Nanoparticles

mAb-functionalized nanoparticles have shown great promise in targeting payload to specific cancer cells. However, very little information is available about the effect of such surface modification on the release of the loaded drug from these nanoparticles. The effects of surface modification by mAb on the release of erlotinib from chitosan nanoparticles (CNPs) were investigated using various mathematic models. Fickian diffusion was elucidated to be the main mechanism of release of erlotinib from nonfunctionalized CNPs irrespective of the pH. In contrast, a strong pH influence was observed in the release of erlotinib from the mAb-functionalized nanoparticles. The lack of a single model to definitely describe the release mechanism coupled to the slow release of erlotinib from antibody-functionalized CNPs in comparison to the nonfunctionalized CNPs strongly suggests that the diffusion pathway of erlotinib was being interfered with by the antibody coupled to the surface of CNPs.