• April 5, 2024

Oddly missing from the pharmacopeial compendia and archival literature are flow resistance data for glass microfiber filters common to the delivered dose uniformity (DDU) testing protocols described in the USP and European Pharmacopeias. The authors undertook a laboratory investigation to provide insight into how filter flow resistance can vary across several similar products available commercially. […]

The Association of Inhalation Toxicologists (AIT) presented a workshop at the 2023 Drug Delivery to the Lungs Conference. The focus was on methods used for in vitro toxicity screening, in vivo study designs, toxicological endpoints and regulatory toxicology. The workshop also covered technical aspects of the generation, characterization and dosimetry of aerosols in toxicology studies. […]

  • December 1, 2023

In the first article, we explored the robustness of the pharmacopeial methodology for the determination of delivered dose uniformity (DDU) for orally inhaled products to bias in volumetric flow rate setting from variations in ambient pressure. In this article, we extend the analysis to evaluate how the determination of the second performance-related critical quality attribute, […]

  • October 17, 2023

In 2020 and 2021, Inhalation published three articles by the Cascade Impaction Working Group of the International Pharmaceutical Aerosol Consortium for Regulation and Science (IPAC-RS): (1) The liability of fine particle dose (FPD); (2) Cascade impactor stage groupings: Poor decisions from degraded data; and (3) Efficient data analysis (EDA): Size, mass and common sense. In […]

  • August 10, 2023

The article describes a series of in vitro test methods that can be used to estimate the total and regional lung doses. The focus of the discussion is on research and development, with the view that the ability to estimate total and regional lung deposition is essential in the design of efficient orally inhaled products. […]

  • April 7, 2023

Much improvement has taken place in evaluating sources of variability in the measures of delivered dose uniformity (DDU) and aerodynamic particle size distribution (APSD). Methods described in the United States Pharmacopeia (USP) and European Pharmacopoeia (Pharm. Eur.) now include dimensions and diagrams for all components critical to their robustness. However, we show that there are […]

  • April 8, 2022

Considering flow conditions in the DPI test system has led to understanding more about why experts have improved the pharmacopeial protocol over time. Still, there are aspects of the fundamentals that are not yet clarified but worth understanding and accommodating in the protocols. The authors believe these include specifications for the solenoid valve, the effect […]

A large gap exists between the relatively straightforward robust methods in the pharmacopeias, developed primarily for product release, and the more elaborate approaches to assist in understanding how inhalers are likely to perform in the hands of the patient or caregiver. The authors propose that there is a middle way forward and believe it is […]

  • December 7, 2021

Impaction-based methods for determining the aerodynamic particle size distributions (APSDs) of aerosolized drug products intended for oral and nasal inhalation are preferred by regulatory authorities because they can be used to directly classify the APSD in terms of the drug substance content of the sampled drug product. One such impactor, the Next Generation Impactor (NGI), […]

  • August 10, 2021

The authors believe that the decision-making framework used to demonstrate product quality consists of both the metrics themselves and the way they are used to make the decision. In the context of inhaler APSD, they contend that good decision-making requires independent assessments of each dimension of the APSD, namely size and mass, which they propose […]