• Publication Date: 02/01/2024
  • Author(s):
    Duke, Daniel J.
  • Organization(s):
    Monash University
  • Article Type: Technical Articles
  • Subjects: Device Design, Devices and Components, Filling/Packaging, Industry Issues and Trends, Product Development/Formulation

We investigated how the change from current generation to next-generation pMDI propellants might affect the technical performance of currently used pMDI hardware, with a focus on actuator designs that assist with achievement of in vitro equivalence. The key finding of the preliminary in vitro studies described is that the changes required to convert pMDI formulations from current HFAs to low-GWP alternatives require careful evaluation, but do not represent an insurmountable barrier.

We divided our studies into three broad categories: 1) Consideration of performance inside, the canister including factors such as API solubility (for solutions), sedimentation or creaming time (for suspensions), material compatibility, and adhesion or loss of the drug onto the canister valve and wall surfaces (both physical forms). 2) Performance of the spray plume beyond the orifice, which drives spray pattern, plume geometry, droplet size and velocity. It is dominated by atomization, mixing and evaporative processes. 3) Performance of the matured aerosol particles, as measured by their delivered dose and size distribution. All three of these categories represent a complex interaction of hardware, propellant and formulation chemistry.

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