Generic dry powder inhalers bioequivalence: Batch-to-batch variability insights

Area of Science:

• Pharmaceutical Sciences
• Respiratory Drug Delivery

Background:

• Dry powder inhaler (DPI) performance, including active pharmaceutical ingredient (API) deposition, is affected by formulation, device, manufacturing, and physiological factors.
• In-market DPIs exhibit batch-to-batch variability, leading to bioinequivalence issues in generic product comparisons, even if clinically minor.

Purpose of the Study:

• To review the implications of batch-to-batch variability in DPIs on bioequivalence study outcomes.
• To identify shortcomings in current regulatory requirements for DPIs.
• To highlight the need for improved in vitro testing methods for reference product batch selection.

Main Methods:

• Literature review of factors influencing DPI deposition and variability.
• Analysis of current regulatory guidelines and their limitations.
• Discussion of formulation and manufacturing contributions to batch variability.

Main Results:

• Batch-to-batch variability in DPIs can compromise bioequivalence study outcomes.
• Existing regulatory frameworks may not adequately address DPI variability.
• Formulation and manufacturing processes are significant contributors to this inherent variability.

Conclusions:

• There is a critical need for enhanced regulatory oversight concerning DPI batch consistency.
• Development of reliable in vitro tests is crucial for accurate reference product batch selection.
• Addressing batch variability is essential for ensuring therapeutic equivalence of generic DPIs.