Segregation and distribution of different particle sizes in the components of a capsule filling machine based on the vacuum drum filler for DPI applications
Isabel Gallego1,2, Thomas Brinz1 & Martin Sommerfeld2
1Syntegon Technology GmbH, Stuttgarter Str. 130, 71332 Waiblingen, Germany
2Institute of Process Engineering, Multiphase Flow Systems, Otto-von-Guericke-University Magdeburg, Hoher Weg 7b, 06120 Halle (Saale), Germany
Summary
Capsule filling using a vacuum drum allows low dose filling of dry powder inhalation (DPI) formulations. Due to the low amount of powder dosage, accurate fill weight and uniform content of active pharmaceutical ingredient (API) in the capsules are critical. API is mixed with the excipients before entering the capsule filling machine, however, it is desired to investigate whether there is any segregation of the powder during the capsule filling process. The capsule filling machine is mainly composed of a feeding station, a powder chamber with a stirrer and a vacuum drum with bores. In this study, the segregation in the vacuum drum was investigated by using a tracer, as well as the influence of different types of stirrers in the powder chamber. A mixture of three lactose with different particle size was studied to analyse the behaviour of small and big particles in the filling process, by replacing either small or big particles with their respective tracer. To obtain the tracer, the lactose was dyed with a solution of methylene blue in ethanol in a fluidized bed, and its concentration was measured with UV-Vis spectroscopy. It was identified that the type of stirrer used in the powder chamber influences the segregation of particles of different sizes in the vacuum drum, showing statistically significant differences.
Key Message
Uniform content in DPI capsule filling is critical. It is possible to measure the content uniformity in the capsules using a tracer and thus evaluate the segregation in the filling machine. The stirrer type in the powder chamber influences the segregation of particles of different sizes in the vacuum drum.