In vitro inhalation behavior of spherically agglomerated steroid particleswith carrier lactose

In order to prepare a dry powder inhalation (DPI) formulation for steroid K SR-592, we designed agglomerates consisting of fine primary drug particles suitable for inhalation by the spherical agglomeration method. The agglomer ates easily disintegrated into the primary particles and were deposited on carrier lactose particles by use of a conventional agitation mixer in a sho rt period, e.g. 2-10 min. The inhalation behavior of the DPI formulation ev aluated with a twin impinger and a cascade impactor in vitro was determined by the mixing time of the agglomerated crystals with the carrier lactose p articles. The DPI formulation prepared by mixing for 2 min showed the highe st respirable fraction value compared with the formulations mixed for other lengths of time.