Since the approval of Dry Powder Inhalers containing Fluticasone Propionate and Salmeterol Xinafoate in 1999, combination inhaled therapies have dominated the COPD market. However, due to the lack of specific guidance of the Office of Generic Drugs as to the abbreviated new drug application submission, there was very little attempts of generic manufactures to come up with bioequivalent DPI formulations until September 2013.
In this study, Raman Chemical Imaging (RCI) was shown to have a potential to address the need to accurately identify and size not only primary drug particles but also aggregates based on their unique spectroscopic properties. RCI method allows extraction of a Raman spectrum from every pixel in the image (spatial resolution approaching 350 nm can be achieved). Thus every image provides spectral and spatial information about any drug to drug or drug to excipient agglomerates that may form.