FaSSGF (Fasted State Simulated Gastric Fluid) is a very useful drug development tool. Tests in this dissolution medium can help reveal how your oral drug is likely to behave in the stomach after drinking a glass of water. Although drugs are not generally absorbed in the stomach, the interaction with stomach fluid can influence the absorption of many drugs greatly; this is especially true of bases.

The stability, solubility and dissolution data you generate from testing in FaSSGF can help identify critical factors influencing your drug’s absorption in the fasted state. These results also support your selection of the appropriate solid state and formulation approach for your drug.  Experiments are performed using standard laboratory equipment (such as USP Dissolution Apparatus 1 or 2). Drug content is analysed using HPLC.

What’s the composition of FaSSGF?

In vivo gastric fluid in the fasted state contains low levels of surfactants refluxed back into the stomach from the upper section of the small intestine. FaSSGF contains the same type and low level of these surfactants (bile salt and phospholipid). These components can contribute to the wetting of a dosage form and drug. FaSSGF has the average acidic pH of fasted gastric fluid and similar osmolarity (about 120 mOsmol/L) too. These are important parameters to control when testing drugs or formulations sensitive to pH and salt content.

How do I make FaSSGF?

You can make FaSSGF in no more than a couple of minutes with 3F Powder® and FaSSGF Buffer Concentrate. These simple steps show how easy it is to prepare 900mL of the medium (the volume we recommend using per dissolution vessel):

Our 'Media Preparation Tool' will give you customized instructions for almost any volume of FaSSGF you want to make and it’s free to use here.

Download our Biorelevant Dissolution Guides here.