AAPS PharmSciTech

, 12:965 | Cite as

Non-impactor-Based Methods for Sizing of Aerosols Emitted from Orally Inhaled and Nasal Drug Products (OINDPs)

  • Jolyon Mitchell
  • Richard Bauer
  • Svetlana Lyapustina
  • Terrence Tougas
  • Volker Glaab
Review Article


The purpose of this article is to review non-impactor-based methods for measuring particle size distributions of orally inhaled and nasal pharmaceutical aerosols. The assessment of the size distributions of sprays and aerosols from orally inhaled and nasal drug products by methods not involving multi-stage cascade impaction may offer significant potential advantages in terms of labor savings and reducing the risk for operator-related errors associated with complex-to-undertake impactor-based methods. Indeed, in the case of nasal spray products, cascade impaction is inappropriate and alternative, and preferably non-invasive methods must be sought that minimize size-related bias associated with the measurement process for these relatively large droplets. This review highlights the options that are available to those involved with product quality assessments, providing guidance on relative strengths and weaknesses, as well as highlighting precautions that should be observed to minimize bias. The advent of Raman chemical imaging, which enables an estimate to be made of the proportion of each particle comprising active pharmaceutical ingredient(s) (APIs), necessitates a re-think about the value of classical microscopy image analysis as now being capable of providing API-relevant information from collected aerosols and sprays.

Key words

aerosol efficient data analysis measurement techniques size distribution spray 



The authors are grateful for the technical advice received from colleagues within the IPAC-RS Cascade Impactor Working Group, as well as recommendations from the IPAC-RS Board of Directors during the internal review process. They also wish to acknowledge helpful scientific discussions with Dr. Julie Suman (NextBreath, LLC) and Mr. William Doub (U.S. FDA, CDER) regarding application of RCI to the study of nasal spray-based formulations.


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Copyright information

© American Association of Pharmaceutical Scientists 2011

Authors and Affiliations

  • Jolyon Mitchell
    • 1
  • Richard Bauer
    • 2
  • Svetlana Lyapustina
    • 3
  • Terrence Tougas
    • 4
  • Volker Glaab
    • 5
  1. 1.Trudell Medical InternationalLondonCanada
  2. 2.Aerosol AnalysisMannkind CorpDanburyUSA
  3. 3.Pharmaceutical Practice GroupDrinker Biddle & Reath LLPWashington DCUSA
  4. 4.Analytical DevelopmentBoehringer IngelheimRidgefieldUSA
  5. 5.Respiratory Drug DeliveryBoehringer IngelheimIngelheim am RheinGermany

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