Metal–Organic Framework Microsphere Formulation for Pulmonary Administration

Although nanoscaled metal–organic frameworks (nanoMOFs) are promising drug carriers, their appropriate formulation remains almost unexplored and basically restricted to intravenous routes. Lungs, beneficiating from a large absorption surface and low enzymatic presence, are a very attractive target for both local and systemic delivery. However, pulmonary nanoMOF formulation is a pending and defying task. Thus, we propose a pioneer nanoMOF-based microsphere system as a potential platform for pulmonary administration. A biocompatible nanoMOF was successfully encapsulated in mannitol by a simple and continuous spray-drying technique. Upon intratracheal administration to rats, the resulting formulation, exhibiting optimal properties ( i.e ., homogeneity, size, density, and spray-drying process yield), was able to release the intact nanoMOF carrier uniformly along the lungs, reaching the bronchioles and alveoli.