A novel ternary component for dry powder inhaler formulations

The concept of the ternary formulations was a major step in the development of dry powder inhaler formulation (1). The use of fine lactose as a ternary component is now well accepted to improve aerolization efficiency of mixtures (2). Pharmaceutical fine lactose is generally made by milling and sieving large tomahawk-shaped crystals of alpha lactose produced by batch cooling crystallization. A common problem associated with this milling process is the generation of amorphous domains which are prone to physical and chemical instability (3). Therefore, it is attractive to avoid amorphous lactose by instead controlling the crystallization to produce crystals of the desired particle size directly. In this study, fine lactose crystals have been produced by a proprietary process, and an initial investigation of their properties in the context of a ternary dry powder inhaler formulation is prepared.