Spray dried composite powders: capsule filling process optimization and aerodynamic performance characterization

Maria Braga¹, Raquel Barros¹, Bruno Ladeira¹, Mariana F. Silva^1,2, Joana Tavares¹ & Eunice Costa¹

¹Hovione FarmaCiencia SA, Sete Casas, 2674 – 506 Loures, Portugal

²Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Portugal

Summary

The main objectives of this work were to assess precision capsule filling of a model spray dried composite powder using a dosator-based unit from MG2, optimize the filling process and evaluate its impact on powder in-vitro aerodynamic performance (AP).

Size 3 capsules were efficaciously filled with three different fill weights (5, 10 and 20 mg), using different dosator diameters (1.9, 2.8, 3.4 and 3.7 mm), powder bed heights (4 – 10 mm) and filling speeds (1000 – 2000 capsules/h). The powder characteristics were also visually assessed throughout filling. The successful integration of tools for homogenizing the powder layer and for removing the excess powder from the dosator were key for filling. For the different fill weights, compaction was varied by adjusting the dosing-chamber-height-to-powder-layer-depth compression ratio.

For capsules filled with 10 and 5 mg the most promising trials of were characterized. A fine particle fraction (FPF) of 72.7 % and 80.1% and a fine particle dose (FPD) of 6.5 mg and 3.3 mg were obtained for the 10 and 5 mg fill weight respectively. Aerodynamic performance results of 20 mg fill weight showed a higher performance for capsules with lower compaction level. The estimated FPF and FPD varied between 69.3 % and 13.4 mg for the lower compaction trial and 57.0 % and 11.1 mg for the trial with higher compaction.

This study showed that the MG2 Flexalab is suitable for the capsule filling of spray dried composite powders with low rejection rates and very good aerodynamic performance which are in accordance with similar studies performed previously