Abstract
Eicosapentaenoic acid ethyl ester (EPA-E) with a high degree of purity is marketed as a medical supply. In vivo pharmacokinetics of EPA-E is examined in detail via animal experiments. Orally administered eicosapentaenoic acid (EPA) is found in triglyceride (TG) in the rat intestine, and is absorbed via the lymphatic system. Moreover, EPA is gradually detected in cholesterol ester and phospholipid (PL) in blood. Whereas EPA is found in low density fractionation of lipoprotein such as chylomicron in the lymph fluid, it gradually transitions to high density fractionation in systemic circulation. EPA is distributed to several tissues such as fat, liver, heart, brain and aorta. Whereas EPA and its metabolized fatty acids are found in TG in fat, they are predominantly found in PL in the brain, liver and heart. EPA transforms systemically into docosahexaenoic acid (DHA) by chain elongation and subsequent desaturation after intestinal absorption. Interestingly, DHA is found in the brain earlier than in blood and the liver, suggesting the synthesis of DHA occurs in not only the liver but also the brain. This hypothesis is also supported by a recent clinical trial.
