Biowaiver monographs for immediate release solid oral dosage forms: aciclovir

Area of Science:

• Pharmaceutical Sciences
• Drug Regulatory Affairs

Background:

• Aciclovir is an antiviral medication used to treat herpes virus infections.
• Regulatory agencies often require bioequivalence (BE) testing for generic drug approvals.

Purpose of the Study:

• To review literature data supporting a biowaiver for immediate-release (IR) aciclovir solid oral dosage forms.
• To assess the suitability of aciclovir for waiving in vivo BE testing based on its properties and available data.

Main Methods:

• Review of scientific literature concerning aciclovir's therapeutic use, therapeutic index, and pharmacokinetics.
• Evaluation of potential excipient interactions and existing bioequivalence/bioavailability (BE/BA) studies.
• Classification of aciclovir according to the Biopharmaceutics Classification System (BCS).

Main Results:

• Aciclovir is classified as BCS Class III (up to 400 mg) and potentially BCS Class IV (800 mg).
• No identified risks for bioinequivalence were found, supported by a wide therapeutic index and non-critical indications.
• Approved excipients and very rapid dissolution of both test and comparator products are key conditions.

Conclusions:

• A biowaiver for IR aciclovir solid oral drug products is considered justified for all tablet strengths.
• Conditions include using approved excipients and ensuring very rapid dissolution for both products.