Bioavailability and Bioequivalence

  • Sam H. Haidar
  • Hyojong (Hue) Kwon
  • Robert Lionberger
  • Lawrence Yu

For systemically acting drugs, absorption is a prerequisite for therapeutic activity when drugs are administered extravascularly. Factors affecting drug absorption have been discussed in previous chapters. This chapter will cover general methods to evaluate bioavailability and bioequivalence. Scientific principles as well as regulatory perspectives related to these two topics will be discussed. Historically, the development of sensitive and precise bioanalytical methods in the 1960s and 1970s allowed for the first time the measurement of very low levels of drug concentrations in biological fluids. As a result, pharmacokinetic profiles of drugs, describing absorption, distribution, and clearance, could be determined. Regulations related to bioavailability and bioequivalence were put into place, considering the latest advances in the science. Currently, bioavailability and bioequivalence play a significant role in the discovery, development, and regulation of new drug products. Additionally, bioequivalence studies are a crucial component of abbreviated new drug applications (ANDAs), leading to market access of safe, effective, and low cost generic drugs.


Drug Product Reference Product Bioequivalence Study Acceptance Limit Variable Drug 
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Copyright information

© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  • Sam H. Haidar
    • 1
  • Hyojong (Hue) Kwon
    • 1
  • Robert Lionberger
    • 1
  • Lawrence Yu
    • 1
  1. 1.Food and Drug AdministrationCenter for Drug Evaluation & ResearchRockvilleUSA

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