• 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 […]

  • 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

Production of inhalable drug particles traditionally involves milling, spray drying, spray freeze drying and supercritical fluid processes. Many of these processes expose the formulation to thermal or mechanical stresses, leading to changes in the particles’ surface and physicochemical properties. Among various particle properties (particle size and size distribution, surface properties, hygroscopicity, electrostatic charge and relative […]

  • April 6, 2021

A key objective of this article is to guide the newcomer to the field, as well as those with familiarity of the topic. Four misconceptions are discussed: Misconception 1: Impactor-sized mass (ISM) always includes data from all impactor stages; Misconception 2: Geometric standard deviation (GSD) is always suitable as the measure of spread of a […]

INFORM2020 is a five-year collaboration of academia and industry to investigate critical parameters that influence the performance of dry powder inhaled (DPI) formulations. In part, the collaboration has been attempting to shed light on key questions through X-ray microscopy, which can offer new insights into the microstructure of inhalable formulations for DPIs. The article also […]

  • December 1, 2020

In Parts I and II of this series, we introduced the concept that the batch release criteria for OIPs can and should dictate the quality constraints on all cascade impactors (CIs) used for batch release testing. This logical proposition applies to the entire set of analytical equipment involved in the making and testing of a […]

  • April 1, 2020

Synchrotron X-rays can provide valuable quantitative information on drug distribution, spray density, droplet and particle properties; metrics that are difficult or virtually impossible to obtain by other means. Unlike many traditional measurement techniques, synchrotron measurements can provide direct evidence of the effects of changes to actuator design and formulation composition on the behavior of a […]

  • November 25, 2019

In this second article, we continue defining the path to necessary and sufficient impactor quality specifications. We introduce the need for a careful definition of sufficiency. This definition, in turn, necessarily introduces the concept of acceptable risk. We have therefore set out the philosophy of establishing impactor quality specifications that are sufficient for meeting the […]

Reducing the variability associated with inhaler testing, notably cascade impaction testing, is a critical, ongoing activity for the industry. Experience suggests that the complete automation of testing is not always the best solution due to the complexity, risk and investment involved. Rather, best practice centers on semi-automation, the use of proven, modular, easy-to-validate automation solutions […]

  • September 23, 2019

Physicochemical properties such as particle size, particle density, aerodynamic particle size, degree of crystallinity, particle shape, surface morphology and chemical composition need to be characterized for inhalable solid-state particles that are designed to target select regions of the respiratory tract.