Preclinical pharmacokinetics of statins

This review summarizes the pharmacokinetic properties of HMG-CoA reductase inhibitors (or statins) reported in animals. Lovastatin and simvastatin are administered as lactone prodrugs in contrast to other statins, which are generally formulated in the pharmacological active hydroxy acid form. Pharmacokinetics vary with the statin and animal species considered. Oral absorption is rapid and the bioavailability low due to an extensive first-pass metabolism. Pitavastatin is the exception, with high bioavailability in all species except monkeys (80% vs. 18%). Plasma protein binding is high for all statins (> 95%) except pravastatin (60%). Regardless of the dosing schedule (single or multiple), animal species and statin, the highest tissue levels are found in the liver--the target organ. Elimination is rapid with metabolism being the main elimination route for all statins, except for pitavastatin, which is only slightly metabolized, and pravastatin, which aside from metabolism is also eliminated by renal excretion. Statins undergo enterohepatic circulation and are recovered mainly in feces via bile, the extent of which is species-dependent. Metabolism varies with the statin and animal species, particularly the beta-oxidation of the dihydroxy heptanoic side chain that occurs primarily in rodents.