Redefining the Threshold for Permeability Classification

According to the 2000 FDA BCS Guidance, a compound that is classified as Class I (highly soluble, highly permeable) is eligible for a BCS biowaiver, which means that a clinical bioequivalence study is unnecessary in case of a new formulation or a generic version of the same chemical entity, for example.  Even without a formal biowaiver, the FDA has more recently taken the position that clinical drug-drug interaction studies are unnecessary for highly permeable and highly soluble compounds that are also substrates of drug efflux transporters such as P-gp. 


The in vitro permeability threshold defined by Absorption Systems’ High Permeability Internal Standard (HPIS) is the lowest available.  This novel internal standard has a Papp about 7-fold lower than that of metoprolol (another compound often used for the same purpose) and fraction absorbed >95% in humans.  With our standard, it is more likely that your compound will be classified as highly permeable, and this can simplify and accelerate your clinical testing.

Contact Us

Customer Login

forgot password

More Information

Resource Library

© 1999-2014 Absorption Systems LP | Legal Notice Site Map Privacy Statement RSS Twitter LinkedIn