Investigating the in vivo behavior and in vitro characteristics purportedly gastro-retentive extended release formulation to enhance the regulatory standard of such products | RFA FD 22 018

Opportunity Information: Apply for RFA FD 22 018

This grant opportunity, RFA FD 22 018 from the U.S. Food and Drug Administration (FDA) within the Department of Health and Human Services, focuses on improving the scientific and regulatory foundation for so-called gastro-retentive extended-release oral drug products. These dosage forms are marketed or described as being able to remain in the stomach or upper gastrointestinal (GI) tract longer than typical oral products, with the goal of improving drug absorption and overall bioavailability. The core problem the FDA is trying to address is that, despite these claims, there has been little to no direct in vivo proof demonstrating true gastric retention for these products in humans. As a result, both regulators and generic drug developers face uncertainty about how to evaluate whether a generic version behaves like the reference listed drug in a way that is clinically meaningful and consistent with the product's proposed mechanism.

The project aims to generate direct, visualizable evidence of gastric retention following oral administration by using imaging technologies. In practical terms, the FDA is looking for research proposals that can track and characterize where a gastro-retentive product goes in the GI tract over time and how long it remains in the stomach region, and then compare that behavior between a reference product and its corresponding generic product. The emphasis on imaging suggests methods that can noninvasively monitor location and transit in vivo, producing objective data rather than relying on indirect assumptions inferred from pharmacokinetic profiles alone. The intent is to connect real-world GI residence behavior to how these dosage forms are expected to work, and to determine whether the reference and generic products show comparable retention patterns.

In parallel with in vivo imaging work, the opportunity calls for exploring and developing in vitro testing methods that can better characterize these formulations and potentially predict or correlate with their in vivo behavior. This includes investigating different laboratory test approaches that might capture key performance attributes of gastro-retentive extended-release products, such as swelling, buoyancy, density changes, mechanical integrity under gastric-like conditions, drug release under relevant pH and motility scenarios, and robustness to physiological variability. The FDA is specifically interested in identifying optimal in vitro methodologies that could be practical for prospective generic applicants to use when building evidence packages to support bioequivalence. A notable aspect is the mention of supporting bioequivalence demonstrations not only for a single strength, but potentially for additional strengths of generic products as well, which often requires sound scientific justification and sensitive, discriminating tests.

From a regulatory perspective, the larger goal is to strengthen standards and decision-making for this category of products by grounding evaluations in clearer, more direct evidence. If successful, the work could help clarify what it really means for a product to be "gastro-retentive" in vivo, how much variability is expected, which product attributes matter most, and what kinds of tests are fit-for-purpose when comparing reference and generic formulations. That, in turn, could reduce ambiguity in review and development, improve consistency in regulatory assessments, and potentially lower barriers for generic competition while maintaining confidence in therapeutic equivalence.

The award structure reflects a targeted research effort rather than a broad multi-award program. The funding instrument type is a cooperative agreement, meaning FDA is likely to have substantial involvement during the project period, such as input on study design, milestones, and data interpretation. The opportunity listed an award ceiling of $1,000,000 and an expected number of awards of one, indicating a single, relatively sizable project intended to produce impactful, publishable, and regulator-relevant outcomes. The opportunity was created on January 12, 2022, with an original application closing date of March 31, 2022. The activity aligns with consumer protection, health, and science and technology research and is tied to CFDA number 93.103. Eligibility is described as "Others" with additional clarifications expected in the full announcement, which typically means the applicant pool may include certain research institutions, academic centers, nonprofits, or other organizations that meet FDA's stated criteria.

Overall, the opportunity is aimed at closing a key evidence gap: verifying and characterizing gastric retention in vivo for products that claim gastro-retentive behavior, and translating what is learned into more reliable in vitro tools that generic developers can use to demonstrate bioequivalence. The practical end result the FDA appears to be seeking is a more rigorous, standardized, and scientifically defensible way to evaluate gastro-retentive extended-release drug products across both reference and generic versions, improving confidence in regulatory outcomes and supporting efficient generic drug development.

• The Department of Health and Human Services, Food and Drug Administration in the consumer protection, health, science and technology and other research and development sector is offering a public funding opportunity titled "Investigating the in vivo behavior and in vitro characteristics purportedly gastro-retentive extended release formulation to enhance the regulatory standard of such products" and is now available to receive applicants.
• Interested and eligible applicants and submit their applications by referencing the CFDA number(s): 93.103.
• This funding opportunity was created on Jan 12, 2022.
• Applicants must submit their applications by Mar 31, 2022. (Agency may still review applications by suitable applicants for the remaining/unused allocated funding in 2026.)
• Each selected applicant is eligible to receive up to $1,000,000.00 in funding.
• The number of recipients for this funding is limited to 1 candidate(s).
• Eligible applicants include: Others (see text field entitled Additional Information on Eligibility for clarification).

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