W.H.Doub1, W.P.Adams2, J.A.Spencer1, L.F.Buhse1, M.M.Nasr1, P.J.Treado3, M.P.Nelson3, D.S.Lester4, A.S.Hussain5, 1DPA, OPS, CDER, FDA, St. Louis, MO, 2OPS, CDER, FDA, Rockville, MD, 3ChemImage, Pittsburgh, PA, 4Pharmacia Corp., 5OPS, CDER, FDA, Rockville, MD
A feasibility study was conducted to examine whether Raman imaging is capable of determining the chemical identity, particle size and PSD of micronized drug substance, principally corticosteroids, in aqueous suspension formulations of nasal sprays. Raman spectra were obtained for the active pharmaceutical ingredient (API) and all excipients for a common formulation of aqueous suspension nasal spray. The formulation was sprayed onto a microscope slide, and brightfield as well as API-specific chemical images were obtained of the dried particles. These images were processed using ChemImage’s software to obtain the PSD of the API particles. Calibration of the imaging system was performed using NIST—traceable microparticles.
API particles were clearly distinguishable from those due to excipients. We also observed API particles adhering to excipient particles. This phenomenon may be an artifact of sample preparation and studies are planned to address this issue. The use of Raman-based chemical imaging enables the qualitative identification of corticosteroid in the presence of microcrystalline cellulose as is found in an aqueous suspension nasal inhalation product. Studies are currently underway to investigate the technique for quantitative particle sizing.
This work was presented at AAPS 2002.