The droplet size distribution produced by the atomization system within a spray d1yer is vital in defining the output particle size distribution, which in turn can strongly influence the subsequent flow, dissolution, ingestion or bioavailability of the final product. This thesis explores the capability of a simple atomizing system for the production of narrow droplet size distributions within an industrially-relevant spray dryer. The combination of constrained droplet size distribution, defined solute concentration and selected processing conditions has been evaluated to determine the influence upon the physicochemical properties of a model active pharmaceutical ingredient, and the dosing characteristics of formulated products. The flow focusing atomizer was demonstrated to be capable of generating distinct droplet size distributions, and able to produce similar performance in the dynamic environment within a spray dryer. Experiments conducted using the inhaled corticosteroid mometasone furoate indicate that droplet size, concentration and drying conditions are important in determining the particle size, texture and thermodynamic properties of the output powder. Analysis of formulations containing the flow-focused mometasone furoate particles defined a clear link between the impaction profile in a cascade impactor and droplet size and spray d1ying conditions.