pH reproducibility of FaSSIF, FeSSIF and FaSSGF prepared from 3F Powder® and corresponding Buffer Concentrates

FaSSIF (Fasted State Simulated Intestinal Fluid), FeSSIF (Fed State Simulated Intestinal Fluid) and FaSSGF (Fasted State Fasted Gastric Fluid) are three of the most common in vitro biorelevant media to simulate in vivo gastrointestinal fluids. Biorelevant media are used during the development of drug products to understand how drugs behave in the gastrointestinal tract.


Variable pH of a solubility or dissolution medium is one of the most common and significant reasons for irreproducible results which affects decision making and interpretation. Maintaining a consistent pH is essential to achieve reproducible solubility and dissolution results of drugs that have different aqueous solubility in the physiological range of the human gastrointestinal tract. This is why controlling pH of biorelevant medium is important.

Buffer Concentrates

Every batch of Buffer Concentrate is made with high quality components (purified water, salts and buffers), manufactured according to strictly defined protocols, released only after analysis of every batch and comes with a Certificate of Analysis. In conjunction with using high quality 3F Powder®, this helps ensure reproducible FaSSIF, FeSSIF and FaSSGF media are prepared every time. See our Media Prep Tool for the exact amounts needed to prepare the medium type and volume you want.


FeSSIF, FaSSIF and FaSSGF dissolution media were prepared using 3F Powder® and five independent batches of each Buffer Concentrates without pH adjustment. The pH of the 5 batches of each medium has been measured after 48 hours storage at room temperature. The results are provided in Figures 1 to 3.


As can be seen from the three Figures, even after 48 hours at room temperature, each medium prepared using 3F Powder with multiple batches of Buffer Concentrate keeps a very consistent pH within +/- 0.05 pH units. This shows that Buffer Concentrates enable preparation of FaSSIF, FeSSIF and FaSSGF media with highly reproducible pH.