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. […]
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Spray drying is used to produce engineered, inhalable dry powders and is a critical tool for new drug developers. It enables production of powders with a tightly controlled range of particle sizes and solid-state properties. Formulators have control over the crystalline and amorphous character and radial distribution of components and particle morphology. This comes from […]
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 […]
CFD modeling for product development requires knowledge of the capabilities of state-of-the-art software and the adoption of a well-controlled simulation workflow. This article will review previous work in this area, illuminating CFD capabilities and the processes and considerations required to create a trusted, useful, predictive simulation to support the product development process. This article shows […]
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 […]
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), […]
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 […]
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 […]
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 […]