bi·o·a·vail·a·bil·i·ty 
(bī′ō-ə-vā′lə-bĭlĭ-tē)
(bī′ō-ə-vā′lə-bĭlĭ-tē)n.
The degree to which or rate at which a drug or other substance is absorbed or becomes available at the site of physiological activity after administration.
bi′o·a·vaila·ble (-lə-bəl) adj.