Nanotherapeutics for pulmonary drug delivery: An emerging approach to overcome respiratory diseases

Pulmonary diseases pose an immense threat to global health. Several nanotherapeutics-based approaches aimed to tackle pulmonary ailments in recent years. The current innovation includes developing nanomedicine for pulmonary delivery of active pharmaceutical ingredients, repurposed drugs, host-directed therapies, or molecules with unconventional mechanisms (such as antimicrobial peptides). But pulmonary delivery of nanomedicines is troublesome due to poor aerodynamic properties for lung deposition and expulsion during inhalation. Nanomedicine can deliver drugs directly into lung tissue via aerosol or dry powder for inhalation to target deep lung deposition and subsequent therapeutic efficacy. Particulate-based drug delivery systems are potentially complementary to conventional inhaled drugs. There are several ways to produce an aerosol or DPI-based therapeutics, and we reviewed some standard methods used to develop nanotherapeutics for inhalation. The developed inhalable formulations can be delivered using inhalation devices, and advanced inhaler device technology has allowed the efficacious delivery of therapeutic compounds via inhalation. In addition, particle engineering is a crucial criterion in developing inhalable formulations to improve drug delivery, enhance therapeutic effects, and perform superior targeting. Technological advancements in inhalation devices have improved the efficiency of lung-based drug delivery mechanisms. This review also enumerated the assessment of pulmonary drug delivery systems, i.e., in vitro, ex vivo, in vivo, or in silico models, which have made significant strides in recent years.