Synthesis and preliminary evaluation of [3H]PSB-0413, a selective antagonist radioligand for platelet P2Y12 receptors

The selective antagonist radioligand [H-3]2-propylthioadenosine-5-adenylic acid (1,1-dichloro-l-phosphonomethyl-l-phosphonyl) anhydride ([H-3]PSB-0413) was prepared by catalytic hydrogenation of its propargyl precursor with a high specific radioactivity of 74 Ci/mmol. In preliminary saturation binding studies, [H-3]PSB-0413 showed high affinity for platelet P2Y(12) receptors with a K-D value of 4.57 nM. Human platelets had a high density of P2Y(12) receptors exhibiting a B-max value of 7.66 pmol/mg of protein. (c) 2005 Elsevier Ltd. All rights reserved.