Reimagining carrier-based formulations for inhalation: Respirable agglomerates

Carrier-based formulations comprising interactive mixtures of micronized drug particles and coarse lactose monohydrate carrier particles were designed to overcome the strong interparticle cohesive forces associated with fine, respirable drug particles. However, the large size of conventional carrier particles imposes inherent constraints, resulting in low and variable lung delivery due to oropharyngeal filtering of particles, flow rate dependent drug delivery, and strong co-formulation effects in fixed dose combination products. Recently, alternative approaches have emerged that replace coarse carrier particles with fine, nanostructured carrier particles. These carriers form respirable agglomerates with micronized or nanosized drug particles, enabling substantially improved lung targeting, greater dose consistency, and reduced sensitivity to inhalation flow rate. Respirable agglomerates also enable stable suspensions of drugs in metered dose inhalers, with improved dose consistency and lung delivery efficiency.