Biowaiver monographs for immediate release solid oral dosage forms: piroxicam

Area of Science:

• Pharmaceutical Sciences
• Drug Regulatory Affairs

Background:

• Piroxicam is a non-steroidal anti-inflammatory drug (NSAID) used for pain and inflammation.
• Assessing bioequivalence (BE) for immediate-release (IR) solid oral dosage forms often requires in vivo testing.
• Biopharmaceutics Classification System (BCS) guides decisions on waiving in vivo BE studies.

Purpose of the Study:

• To review literature and experimental data to determine the feasibility of a biowaiver for piroxicam IR solid oral dosage forms.
• To evaluate piroxicam's properties in relation to BCS classification and potential for in vitro assessment of bioequivalence.

Main Methods:

• Literature review of piroxicam's solubility, permeability, pharmacokinetics, and therapeutic index.
• Analysis of excipient interactions and existing bioequivalence/bioavailability data.
• Evaluation of in vitro dissolution data and comparison with regulatory guidelines.

Main Results:

• Piroxicam is classified as BCS Class II, indicating high solubility and low permeability.
• While overall absorption (AUC) is unlikely to be affected, the rate of absorption (Cmax) can be formulation-dependent.
• Current in vitro dissolution methods may not fully capture Cmax differences for BCS Class II weak acids.

Conclusions:

• A biowaiver for piroxicam IR solid oral dosage forms is feasible under specific conditions.
• Conditions include: approved excipients, rapid and similar dissolution profiles (≥85% in 30 min across pH 1.2, 4.5, 6.8), and demonstrated dissolution profile similarity.
• If these conditions are not met, in vivo bioequivalence studies are necessary.