[PET imaging to study the functional impact of P-glycoprotein in neuropharmacokinetics]

P-glycoprotein (P-gp) is a major efflux transporter at the blood-brain barrier (BBB) where it controls the brain distribution of many drugs. Clinical translation of preclinical data obtained using invasive methods in animals is difficult due to species differences in P-gp expression and function. Positron emission tomography (PET) is an imaging technique allowing for the determination of the tissue kinetics of microdose of radiolabeled compounds. Three radiolabeled substrates of the P-gp have been developed for clinical use: [¹¹C]verapamil, [¹¹C]-N-desmethyl-loperamide and [¹¹C]metoclopramide. These innovative tools enabled the study of P-gp in humans in various patho-physiological conditions including neurological diseases. This approach is also useful to predict the risk for drug-drug interaction caused by P-gp inhibitors at the BBB and address its impact for neuropharmacokinetics in vivo in humans.