Biocompatible polymeric micelles with polysorbate 80 for use in brain targeting

In this paper, the synthesis and characterization of novel amphiphilic graft copolymers based on an alpha,beta-poly(N-2-hydroxyethyl)-D, L-aspartamide (PHEA) backbone and D, L-polylactic acid (PLA) hydrophobic side chains are reported. These copolymers were obtained starting from PHEA-ethylenediamine (PHEA-EDA), which was functionalized with polysorbate 80 (PS(80)) and/or PLA in order to obtain the PHEA-EDA-PS(80)-PLA and PHEA-EDA-PLA samples, respectively. The degrees of derivatization, DD(PS80) and DD(PLA), of PHEA-EDA-PS80-PLA, calculated by (1)H-NMR, resulted in being 1.2 +/- 0.03 mol% and 0.54 +/- 0.05 mol%, respectively, while that of PHEA-EDA-PLA was found to be 0.60 +/- 0.05 mol%. Size exclusion chromatography (SEC) analysis confirmed the occurrence of derivatization, the molecular weight values being close to the theoretical ones. Polymeric micelles from PHEA-EDA-PLA and PHEA-EDA-PS(80)-PLA copolymers were obtained by using the dialysis method and were characterized in terms of mean size, zeta potential, critical aggregation concentration (CAC), and surface composition by x-ray photoelectron spectroscopy (XPS) analysis, which demonstrated the presence of PS(80) onto the PHEA-EDA-PS80-PLA micelle surface. In vitro experiments demonstrated that these systems had no cytotoxic effects on 16 HBE, Caco2, HuDe and K562 cell lines, and no haemolytic activity. Moreover, both PHEA-EDA-PS80-PLA and PHEA-EDA-PLA micelles were able to penetrate into Neuro2a cells and, in the case of PS(80) decorated micelles, to escape from phagocytosis by the J774 A1 macrophages.