Major depressive disorder (MDD) represents a widespread mental health condition. Efficiently moving therapeutic substances across the blood-brain barrier (BBB) remains a critical obstacle in addressing depressive disorders. AC5216, identified as a translocator protein (TSPO) ligand and considered a potential treatment for major depressive disorder (MDD), faces limitations due to its subpar druggability and oral bioavailability. In this context, an amphiphilic polymer composed of polyethylene glycol, poly-l-lysine, and poly(lactic-