Many attendees expressed particular interest in the talk by Elise Burmeister Getz on “Pharmacokinetic Behavior of Fluticasone Propionate and Salmeterol from Advair Diskus: The Consequences of Batch Variability,” even without realizing its connection to the citizen petition filed by Sandoz requesting that the FDA refrain from approving any ANDAs for generic copies of Advair Diskus 100/50 unless PK bioequivalence testing could be shown to account for batch-to-batch variability in the reference drug. While the FDA denied the citizen petition for technical reasons in March 2017, the agency issued a complete response letter to Mylan’s ANDA for a generic Advair at about the same time.
The speakers in another session – including Andy Clark, Jeff Weers, Dennis Sandell, and Jolyon Mitchell, who appeared via Skype – addressed a number of issues related to the determination of in vitro bioequivalence, including the use of various cascade impactor inlets and parameters such as the “Q index,” which quantifies how flow rate effects total lung dose, and the inertial impaction parameter. On the final day of the meeting, presenters introduced new techniques for characterizing aerosols, including a description of an “acini-on-chip” model of flow within the alveoli by Josué Sznitman of the Technion – Israel Institute of Technology and a talk on the use of phase Doppler anemometry and high speed imaging techniques for characterizing MDI plumes by Hank Versteeg of Loughborough University.
Novel techniques for assessing formulations in development were also a major trend in the workshops, with Capsugel offering a workshop titled, “Engineered Particle Platform for Rapid Assessment of Inhaled Formulations: In Vitro and In Vivo Correlations”; FLUIDDA presenting a workshop titled, “Functional Respiratory Imaging (FRI): Assessment of Lung Health to Optimize Respiratory Drug Delivery”; and Proveris Scientific’s workshop, “Using a Novel Rapid Screening Technique to Streamline pMDI Formulation and Device Development.”