A cross-validation study by Catalent Pharma Solutions has shown the Malvern Spraytec laser diffraction-based particle size analyser to be a robust, efficient and cost-effective alternative to cascade impaction techniques for routine screening of nebuliser formulations. Researchers from Catalent's Respiratory, Analytical and Biotechnology group, based in North Carolina's Research Triangle Park in the US, conducted the study.
The study, which was first presented at Drug Delivery to the Lungs 19 in Edinburgh, Scotland in December 2008, used both the Spraytec and the Next Generation Impactor (NGI) to determine the particle size distributions of two formulations delivered from two different nebulisers. Results from both measurement techniques for the fine particle fraction - the fraction of a dose that deposits in the lungs - were equivalent, demonstrating that the complementary technique of particle size analysis by laser diffraction is directly comparable with cascade impactor measurements.
The company says the use of particle sizing techniques is critical in understanding inhaled drug and device performance. While cascade impactor testing remains essential for validation and submission purposes, the results of the study show that laser diffraction can be used for routine testing. It offers fast, efficient access to the information needed to quantify device/formulation performance and to assess the ranges available for safe and effective development. As such it is a valuable tool for cutting the costs and timelines associated with inhalation product development, the company adds.
Spraytec reliably measures aerosolised droplet size distributions during spraying. Measurements can be carried out very rapidly and over a broad range of particle sizes (typically 0.1 - 2000 microns), delivering detailed dynamic information.