Answer: Submit the research protocol to the IRB for review and submit an IND application to the FDA before conducting the research
Explanation:
From the question, we are informed that an investigator proposes to study a market approved product sold to treat high blood pressure in individuals over age 12 and that this study will look at using a liquid formulation for children under age 12.
We are further told that the drug sponsor hopes that the information from the research can be used to change the labeling for use of the drug in children.
The investigator’s most appropriate course of action will be to submit the research protocol to the IRB for review and submit an IND application to the FDA before conducting research.