Figure 1.
Nasal airway anatomy with the olfactory region (OR).
Geometric complexity and narrowness of the nasal airway prevents effective intranasal drug delivery. To avoid contact loss to the wall, particles should closely follow the middle plane (a) of the nasal passage, which exhibits three-dimensional spatial features. A simple delivery system is shown in (b) which consists of components with the following four functions: (1) aerosol generation (inhaler), (2) particle charging, (3) particle focusing, and (4) particle navigation control. A more elaborate system can have supports to stabilize the device relative to the human head.
Figure 2.
Electric field and particle trajectories within the quadrupole geometry with three electrode voltage layouts: (a) layout 1, (b) layout 2, and (c) layout 3.
Figure 3.
Dynamics of 2-D intranasal delivery: (a) airflow, (b) electric potential field, (c) particle trajectories with electrophoretic forces, and (d) particle trajectories without electrophoretic forces.
In the electric field, the red color represents zero voltage and the blue color represents negative voltages.
Figure 4.
Particle trajectories with and without electric forces: (a) partial release; (b) pointed release.
Figure 5.
Comparison of olfactory dosages with and without electric forces in the 2-D model on a logarithmic scale.
The olfactory dosages can be two orders of magnitude higher with applied E-forces than without.
Figure 6.
Diagram of electrode configuration and four particle-pointed-release positions.
There are four groups of electrodes in tandem, with one group on each side of the nose and one group lining above each of the two nasal ridges. L: left; R: right; LS: left side; RS: right side.
Table 1.
Electric potentials on the electrodes of top left (L) and left side (LS) rows.
Figure 7.
Inhalation airflow streamlines (a) and snapshots of particle transport (b) at different instants inside the nasal cavity.
Figure 8.
Comparison of deposition patterns with and without electrophoretic forces for particles released (a) over the entire area of the left nostril, and (b) at point B of the left nostril.
Figure 9.
Snapshots of particle locations (a), electric potential (b) and electrophoretic force in x direction (c) in the left nasal passage for particles released at point B.
Figure 10.
Comparison of olfactory dosages with and without electric forces in the 3-D model on a logarithmic scale.
The olfactory dosages can be two orders of magnitude higher with applied E-forces than without.