Last Friday, FDA issued four (4) guidance documents that establish the FDA’s current thinking on requirements for establishing sameness and bioequivalence of topical products. They cover in vitro permeation testing, in vitro release studies, Q3 characterization studies, and studies required for corticosteroids of medium and high potency.
While there have been many documents and discussions about these issues in topical drug delivery, these four (4) guidances bring together bits and pieces of previous FDA discussions and documents impacting topical products being developed into complex topical dosage forms for specific routes of administration. For instance, the guidance on in vitro permeation studies “does not address drug products that are administered via ophthalmic, otic, nasal, inhalation, oral, or injection-based routes, or that are transdermal or topical delivery systems (including products known as patches, topical patches, or extended release films)”. Note that all the first three of the draft documents were developed under the Drug Competition Action Plan and the fourth revises and updates the guidance Topical Dermatologic Corticosteroids: In Vivo Bioequivalence that was issued in June 1995.
The four (4) draft guidance documents are:
- In Vitro Permeation Test Studies for Topical Drug Products Submitted in ANDAs Guidance for Industry (45 pages, here)
- In Vitro Release Test Studies for Topical Drug Products Submitted in ANDAs (17 pages, here)
- Physicochemical and Structural (Q3) Characterization of Topical Drug Products Submitted in ANDAs (16 pages, here)
- Topical Dermatologic Corticosteroids: In Vivo Bioequivalence (23 pages, here )
Happy reading to all, and after you have digested all of the information, you likely will not have any questions about how to establish bioequivalence for these products. Right!!! But you will have a skin-tight understanding of how to approach the required studies and generate the appropriate data for ANDA submission.
