Back to basics: The development of a simple, homogenous, two‐component dry‐powder inhaler formulation for the delivery of budesonide using miscible vinyl polymers

It was hypothesised that formulating a dry‐powder inhaler (DPI) using a refined, smooth grade of lactose, without fines and a polymer coated drug microparticle should produce an homogeneous formulation in which aerosolisation behaviour could be modified. Hence, the aim of this study was to develop a simple two component polymer coated‐budesonide/lactose blend in which the drug microparticle adhesive forces could be optimised by modifying the drug coating in order to improve aerosolisation from a DPI. Budesonide microparticles (1.83 ± 0.03 µm) were coated with the vinyl polymers by adsorption and then spray‐dried. The drug was blended with three different types of lactose, checked for uniformity of mixing and loaded into Pulvinal® devices. The median volume particle size of all but one of the polymer coated microparticles remained below 4 µm after spray‐drying and the content uniformity for all the blends >96%. Coating the budesonide with 0.01% poly(vinyl alcohol) increased the fine particle fraction (FPF) in the next generation impactor (NGI) from 29.1 ± 0.7% to 52.8 ± 1.0% and reduced the force of adhesion from 410 ± 182 to 241 ± 82 nN with smooth lactose. This illustrates that vinyl polymers could effectively modify adhesive interactions without the need for ternary components such as fines. © 2007 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:1257-1267, 2008