Biowaiver monographs for immediate release solid oral dosage forms: acetazolamide

Area of Science:

• Pharmaceutical Sciences
• Drug Regulatory Affairs

Background:

• Acetazolamide is an immediate-release (IR) solid oral dosage form.
• Regulatory decisions regarding waivers for in vivo bioequivalence (BE) testing are crucial for drug product approvals.

Purpose of the Study:

• To review literature data for acetazolamide to determine if a waiver of in vivo bioequivalence testing is justifiable for IR solid oral dosage forms.
• To assess acetazolamide's characteristics, including Biopharmaceutics Classification System (BCS) properties, therapeutic index, pharmacokinetics, and potential for excipient interactions.

Main Methods:

• Literature review of acetazolamide's solubility, permeability, and pharmacokinetic properties.
• Evaluation of data on excipient interactions and reported bioequivalence (BE)/bioavailability (BA) issues.
• Assessment of acetazolamide's classification within the Biopharmaceutics Classification System (BCS).

Main Results:

• Data on acetazolamide's solubility, oral absorption, and permeability are inconclusive for definitive BCS classification.
• A conservative approach suggests that a biowaiver is not justified for new multisource acetazolamide products.
• SUPAC level 1 and 2 post-approval changes, along with most EU Type I variations, may be approved without in vivo BE studies.

Conclusions:

• Due to insufficient conclusive data, a biowaiver for in vivo bioequivalence testing is not recommended for new multisource acetazolamide IR products.
• Regulatory flexibility exists for specific post-approval changes, allowing for waivers of in vivo BE studies under certain conditions (e.g., SUPAC, EU Type I variations).
• Further research may be needed to conclusively classify acetazolamide within the BCS for potential future biowaiver considerations.