The agency opened up a public docket seeking comments to aid in the development of two draft guidances it published in October 2017 relating to pH-dependent drug-drug interactions.

The documents — the In Vitro Studies draft guidance and the Clinical Drug Interaction Studies draft guidance — are meant to assist drug developers in planning and evaluating DDI studies during the drug development process.

The FDA is seeking stakeholder input to help construct a framework for assessing pH-dependent DDIs because “it is important to gauge a drug’s susceptibility to them during drug development, characterize the DDI’s effect with clinical studies when necessary and post the study results on drug labeling.”