Biowaiver Monograph for Immediate-Release Solid Oral Dosage Forms: Amoxicillin Trihydrate

Area of Science:

• Pharmaceutical Sciences
• Drug Development
• Regulatory Science

Background:

• Amoxicillin trihydrate is a widely used antibiotic in immediate-release solid oral dosage forms.
• In vitro bioequivalence (BE) testing, or biowaiver, can streamline drug approval processes.
• Regulatory guidelines permit biowaivers under specific conditions based on drug properties.

Purpose of the Study:

• To review literature and experimental data for waiving in vivo bioequivalence (BE) testing for amoxicillin trihydrate immediate-release products.
• To assess the suitability of amoxicillin trihydrate for biowaiver based on Biopharmaceutics Classification System (BCS) criteria.
• To define conditions under which a biowaiver can be recommended for amoxicillin trihydrate formulations.

Main Methods:

• Literature review and analysis of experimental data.
• Evaluation of solubility and permeability characteristics (BCS classification).
• Consideration of therapeutic uses, index, excipient interactions, dissolution, and bioavailability studies.

Main Results:

• Amoxicillin doses up to 875 mg are BCS Class I; 1000 mg is BCS Class II; >1000 mg is BCS Class IV.
• Biowaiver is recommended for amoxicillin trihydrate immediate-release products with single API at 875 mg or less.
• Specific conditions include approved excipients, WHO/FDA/EMA methods, and rapid dissolution.

Conclusions:

• The biowaiver procedure is suitable for amoxicillin trihydrate immediate-release formulations up to 875 mg.
• Formulations exceeding 875 mg or using non-standard excipients require in vivo BE studies.
• This facilitates regulatory approval and reduces the need for clinical BE testing for certain amoxicillin products.