The brain volume of distribution of DA, DA‐PL, and DA‐PIL in the brain parenchyma measured by internal carotid artery perfusion. DA, free dopamine; DA‐PLs, encapsulated dopamine PEGylated liposomes; DA‐PILs, encapsulated dopamine PEGylated immunoliposomes; SD, control Sprague Dawley rat group; PD, experimental group of rat model of Parkinson's disease (PD). Data are means ± SEM (n = 3,4). ***P < 0.001, significantly different from DA, ##
P < 0.01, ###
P < 0.001, significantly different from DA‐PL.