Aerosol delivery systems, compositions and methods

An apparatus comprising:

• an entrainment chamber defining an entrainment volume, the entrainment chamber including a gas inlet port, an aerosol inlet port and an outlet port, the gas inlet port configured to fluidically couple a gas source to the entrainment volume, the aerosol inlet port configured to receive an inlet aerosol produced by an aerosol generator, the entrainment chamber configured such that at least a portion of the inlet aerosol is entrained into a flow of a gas within the entrainment volume to produce an entrained aerosol flow at the outlet port;
• and
• a particle selection chamber including a cannula coupling port configured to be coupled to a nasal cannula, the particle selection chamber configured to receive the entrained aerosol flow from the outlet port of the entrainment chamber and produce an outlet aerosol flow, the particle selection chamber including an obstructive structure configured to remove particles from the entrained aerosol flow such that a volumetric median diameter of the outlet aerosol flow is less than a volumetric median diameter of the inlet aerosol,
• the cannula coupling port including a cannula nozzle and a coupling portion, the coupling portion configured to be coupled to the nasal cannula such that an inner wall of the cannula nozzle and an inner wall of the nasal cannula form a substantially continuous surface.

An apparatus comprising:

• an entrainment chamber defining an entrainment volume, the entrainment chamber including a gas inlet port, an aerosol inlet port, and an outlet port, the gas inlet port configured to fluidically couple a gas source to the entrainment volume, the aerosol inlet port configured to receive an inlet aerosol produced by an aerosol generator, the entrainment chamber configured such that a first portion of the inlet aerosol is entrained into a flow of a gas within the entrainment volume to produce an entrained aerosol flow at the outlet port and a second portion of the inlet aerosol is collected within the entrainment chamber;
• a particle selection chamber including a cannula coupling port configured to be coupled to a nasal cannula, the particle selection chamber configured to receive the entrained aerosol flow from the outlet port of the entrainment chamber and produce an outlet aerosol flow, the particle selection chamber configured to extract a portion of the entrained aerosol from the entrained aerosol flow such that a volumetric median diameter of the outlet aerosol flow is less than a volumetric median diameter of the inlet aerosol;
• and
• a recirculation port defined by one of the entrainment chamber or the particle selection chamber, the recirculation port configured to receive one of the second portion of the inlet aerosol or the extracted portion of the entrained aerosol, the recirculation port fluidically coupled to the aerosol generator via a recirculation pathway that excludes at least one of the entrainment chamber or the particle selection chamber.