What are the ‘fasted’ and ‘fed’ states?
The ‘fasted state‘ refers to the conditions of the gut fluids before a meal, whereas the ‘fed state’ refers to the conditions of the gut fluids after a meal. In humans, the concentration of natural surfactants that can improve drug performance (such as bile salts and phospholipids) are typically much higher in the fed state in comparison with the fasted state!
What is the impact of ‘fasted’ and ‘fed’ states for oral drug development?
The difference in concentration of natural surfactants, bile salts, phospholipids and enzymes can drastically change a compound’s dissolution profile (how much and how quickly it dissolves) and its so-called apparent solubility (the maximum dissolved concentration in the gut fluid). For poorly water-soluble compounds, performance can be improved in the fed state! So, it’s important to test in fed and fasted biorelevant media and choose the right formulation development path to obtain a final drug product that performs well.
‘Fed’ and ‘fasted’ Biorelevant Media selection for poorly soluble compounds
Poorly water-soluble drugs, with higher affinity for fatty molecules rather than water (lipophilic compounds) can display improved performance (higher dissolution rates and greater solubility) in the fed vs. the fasted state. Typically, fasted and fed state intestinal Biorelevant Media (FaSSIF and FeSSIF) are used for immediate release neutral and acidic compounds. For bases, gastric media (FaSSGF and FeSSGF) is also necessary as they could precipitate when moving from the low pH of the stomach to the higher pH of the intestine.
‘Fasted’ Biorelevant Media selection for highly soluble compounds
Highly water-soluble drugs are a little more straightforward. For immediate release neutral and acidic compounds, testing solubility and dissolution in fasted state intestinal Biorelevant Media (FaSSIF) is recommended. For bases, additional testing in fasted state simulated gastric media (FaSSGF) is required to identify precipitation issues.
Fed and fasted states can have a huge influence on oral drug delivery, with the fed state potentially improving the performance of poorly soluble drugs. Knowing your oral drug’s chemistry is crucial to understanding whether fed and fasted states can affect its performance. Our selection of easy to use biorelevant media could greatly assist you during various stages of drug development!