Dry powder inhalers (DPI) have gained much interest in pharmaceutical field due to their effectiveness, reproducibility, simplicity to use and affordability. The determination of the aerodynamic particle size distribution (aPSD) is key for the development and quality control of DPIs. These in vitro tests allow the establishment of the deposition profile of the active pharmaceutical ingredient (API), leading ultimately to the prediction of the in vivo performance and its clinical effects. A clear relationship between in vitro and in vivo data is considered an important goal as part of the formulation development.
The main goal of this work consists on the evaluation of the aerodynamic performance of three DPI formulations of the same API and the characterization by chemical imaging of its deposition profiles.
In order to improve the correlation between in vitro and in vivo data, aPSD was measured applying an air flow that mimics the human condition. In this work a next generation impactor (NGI) coupled with a breathing simulator (BRS) was used, allowing the modulation of the air flow to be similar to the desired breathing profile.
After the cascade impactor tests all the stages were collected and analyzed by chemical imaging and the API quantified by High Performance Liquid Chromatography (HPLC), to determine the deposition profile of the different formulations.
Preliminary results acquired by Raman spectroscopy are aligned with the HPLC data. This fact reveals a good starter point to implement a new methodology of API quantification and establish a method correlation with in vivo performance.