Preclinical Pharmacokinetic Properties of the P-Glycoprotein Inhibitor GF120918A (HCl salt of GF120918, 9,10-Dihydro-5-methoxy-9-oxo-N-[4-[2-(1,2,3,4-tetrahydro-6,7-dimethoxy-2-isoquinolinyl)ethyl]phenyl]-4-acridine-carboxamide) in the Mouse, Rat, Dog, and Monkey