Softpellets for high dose pulmonary delivery
Christian Etschmann, Regina Scherließ
Department of Pharmaceutics and Biopharmaceutics, Kiel University, Grasweg 9a, 24118 Kiel, Germany
High dose formulations are increasingly gaining attention in the field of inhalation. Soft agglomerates seem to be a suitable technique to produce good flowing powders that are stable enough to allow powder handling and dosing, but are soft enough to be deagglomerated and get dispersed during inhalation utilising a suitable inhaler. Typically softpellets are produced by preagglomeration of micronised powders using a screw feeder. Thereafter the pre- agglomerates are rounded in a spheroniser. In this study a new technique utilising vibration is applied to produce placebo and active pharmaceutical ingredient (API) softpellets. In the first step of this method pre-agglomerates are formed by forcing the powder through a sieve resulting in oblong powder agglomerates. The particle size of the resulting product can be controlled by the selection of the sieve for pre agglomeration. Afterwards the pre-agglomerates were rounded on a vibrating slide. In this study three different sizes of placebo softpellets were compared with respect to particle size and sphericity. In a last step the fines and coarse particles were separated with sieves. It has been shown that smaller particles show a higher sphericity and higher stability than larger particles. Furthermore the bulk density of larger particles was higher compared to the smaller ones. First results of aerodynamic characterisation of an API batch consisting of rifampicin are very promising. They seem to get well deagglomerated with the Turbohaler and produce a high fine particle fraction of 52.90 %.