PK 11195-D3 is the isotope labelled analog of PK 11195 (P571500), a high affinity peripheral benzodiazepine receptor (PBR) ligand. PK 11195 has been shown to regulate protein phosphorylation in rat brain mitochondria under control of Ca2+. PK11195 promotes mitochondrial apoptosis and blocks P-glycoprotein (Pgp)-mediated drug efflux to chemosensitize cancer cells.