Bioavailability

Bioavailability: The relative amount of a drug or agent that reaches the circulation (and therefore has a better chance to reach the cancer cells). Theoretically, an agent that is given through injection has higher bioavailability because it is 100% intact when it first enters the blood (although it may later be broken down or otherwise cleared by the body). Supplements, nutraceuticals, and pharmaceuticals administered by mouth, on the other hand, may break down in the digestive system so much that they enter the blood stream at only a fraction of their original intensity. The more intact an agent is when it reaches its target, the better it works.