Spray dried powders for nasal application – Influence of particle morphology and filling process on aerosol generation
Angelika Jüptner1, Ségolène Sarrailh2 & Regina Scherließ1
1Department of Pharmaceutics and Biopharmaceutics, Kiel University, Grasweg 9a, 24118 Kiel, Germany
2Aptar Pharma, Route des Falaises, 27100 Le Vaudreuil, France
Spray drying is an interesting formulation alternative to interactive blends, which are commonly used in oral inhalation. Particles of spherical morphology can be obtained by this technology. By changing process parameters or adding excipients morphology, density and size can be tailored to modify dispersion characteristics and location of deposition. Being already used in pulmonary delivery they are also an opportunity in nasal application. In this study it was shown that spray dried formulations can be filled with equipment like a vacuum drum system. The nasal deposition of spherical particles is affected by the filling process, if the assessment of deposition in a nasal cast is conducted without airflow. During the filling process powder plugs are formed which are less dispersible than the manually filled powder. A similar deposition profile to manually filled powders is seen with an airflow of 15 L/min because the dispersion of the built plugs is improved. Besides the filling process the morphology of particles also has an impact on the deposition profile. Particles with a wrinkled morphology tend to have a lower deposition in the middle and upper turbinates at an airflow of 15 L/min than at 0 L/min compared to the spherical particles. Also the postnasal fraction is increased markedly compared to spherical particles. Wrinkled particles with HPMC show the same trend as particles with leucine but they have a lower postnasal fraction. For targeting the upper turbinates (e.g. for nose-to-brain delivery via the olfactory region) a wrinkled morphology can be disadvantageous, if administered to an airflow of 15 L/min.