FaSSIF 101

What is FaSSIF?

FaSSIF (Fasted State Simulated Intestinal Fluid) is a biorelevant test medium that replicates small intestinal fluid after drinking a glass of water. Generating in vitro dissolution profiles of a Test Product and Reference in this Biorelevant Medium reveals the rates of drug release in vivo. If in vitro drug release profiles are complete, it is likely that this medium can be used to assess chances of achieving bioequivalence of the Test Product to the Reference.  

What is in FaSSIF?

FaSSIF contains the same type and level of physiological surfactants (biliary secretions) present in the intestinal fluid it replicates. These natural surfactants are critical because they form mixed micelles which can enhance drug solubility and dissolution greatly. This solubility enhancement is particularly important for BCS Class 2 and BCS Class 4 (poorly water-soluble drugs). FaSSIF has the average pH of fasted intestinal fluid and similar osmolarity too. These are important parameters to control when testing drugs or formulations sensitive to pH and salt content.

How do I make FaSSIF?

FaSSIF can be prepared in less than a couple of minutes with 3F Powder and diluted FaSSIF Buffer Concentrate.

For more detailed information on FaSSIF download the Technical Data Sheet here.

Download our Biorelevant Dissolution Guides here.