PET radiotracers for imaging P-glycoprotein: the challenge for early diagnosis in AD.

PET radiotracer development to target in vivo P-glycoprotein (P-gp) could be an important strategy for the early diagnosis of neurodegenerative disorders such as Alzheimer's disease (AD). Indeed, as a dysfunction of P-gp is responsible for the accumulation of β-amyloid plaques (a hallmark of AD) in brain parenchyma, P-gp is the cause of AD onset. P-gp substrates and inhibitors are useful for imaging the activity or expression of this protein, respectively; herein we discuss the in vivo evaluation of some ¹¹C radiotracers with P-gp-inhibitory activity, such as [¹¹C]MC18 and [¹¹C]MC113, as well as P-gp substrates [¹¹C]MC266 and [¹¹C]MC80. Moreover, the radiosynthesis of all these P-gp probes is reported.