Can low-dose combination products for inhalation be formulated in single crystalline particles?

This study aims to produce and test the performance of novel crystalline respirable particles containing two low-dose active ingredients and mannitol. This technique overcomes the usual requirement of blending with lactose carriers in formulating combination inhalation products. Ternary powders were produced by co-spray drying solutions containing an inhaled corticosteroid (ICS), a long-acting β2-agonist (LABA), and mannitol as a crystalline excipient. Two formulations comprising widely used ICS and LABA were studied: budesonide/formoterol fumarate dihydrate/mannitol (B/F/M-SD) and fluticasone propionate/salmeterol xinafoate/mannitol (F/S/M-SD). Various physicochemical properties of the powders were analyzed. Aerosol performance was evaluated by dispersing each powder from an Aerolizer® at 60 and 100 L/min into a Next Generation Impactor. We obtained partially hollow spherical particles (volume median diameters of 2 μm) with drug-enriched surfaces. Both formulations contained α-mannitol, and the ICSs were crystalline. The content of each drug component in the powder was found to conform to the theoretical dose. The ternary powders generated high fine particle fractions (>50% of the loaded dose), with concomitant drug deposition on the impactor stages. The aerosol performance of B/F/M-SD was maintained after storage over silica gel at 22 °C for 11 weeks. In conclusion, co-spray dried particles of ICS/LABA/M-SD were largely crystalline, stable and showed excellent aerosol performance. They may provide an attractive alternative strategy to develop combination products without lactose blends.