### Question
How does DRUGS AND DEVICES define bioavailability?


### Answer
Under *21 U.S.C. § 355*, **bioavailability** is defined as:

> the rate and extent to which the active ingredient or therapeutic ingredient is absorbed from a drug and becomes available at the site of drug action

#### Citation:
  - *21 U.S.C. § 355*
  - Heading: **CHAPTER 8-NARCOTIC FARMS > SUBCHAPTER V-DRUGS AND DEVICES > Part A-Drugs and Devices**

