Dry powder inhaler

Abstract

A dry powder inhaler has a dispersion chamber containing beads. A dose of dry powder is released into the chamber, or into an inlet tangentially joining into the chamber. As the patient inhales on a nosepiece or mouthpiece, air moves circularly through the dispersion chamber to drive the beads. The beads roll, bounce, and collide repeatedly with the drug particles on the chamber surfaces or on the beads. The smaller active drug particles are separated from larger carrier particles and from each other, and a powder aerosol is created and inhaled by the patient. The beads are preferably lightweight, so that they can be rapidly accelerated and moved, even with nominal inspiration. The flow resistance of the inhaler is also reduced via the beads, allowing greater airflow and powder dispersion, without any increased effort by the patient.

1 . An inhaler comprising: 
 a dispersion chamber having an open central interior area;    a curved outer wall in the dispersion chamber forming a bead race in the dispersion chamber;    at least one bead in the dispersion chamber, with the bead having a diameter or characteristic dimension of at least 50 to 90% of an interior height of the dispersion chamber;    an inlet connecting into the dispersion chamber; and    an outlet connecting into the dispersion chamber and spaced apart from the inlet.    
   
   
       2 . The inhaler of  claim 1  wherein the dispersion chamber is disk-shaped.  
   
   
       3 . The inhaler of  claim 1  wherein the bead race has a radius of curvature greater than a radius of curvature of the bead.  
   
   
       4 . The inhaler of  claim 2  wherein the dispersion chamber has a flat bottom surface and a flat top surface adjoining the bead race.  
   
   
       5 . The inhaler of  claim 1  further comprising means for retaining the bead in the chamber.  
   
   
       6 . The inhaler of  claim 1  wherein the bead has a diameter or characteristic dimension which allows the bead to move around chaotically in the dispersion chamber when a patient inhales on the outlet.  
   
   
       7 . The inhaler of  claim 1  further comprising a dose platform adjacent to the inlet, for holding a dose of a dry powder pharmaceutical.  
   
   
       8 . The inhaler of  claim 1  further comprising an obstruction in the dispersion chamber to cause the bead to move chaotically.  
   
   
       9 . The inhaler of  claim 1  wherein from 2 to 10 round beads are provided in the dispersion chamber.  
   
   
       10 . The inhaler of  claim 1  wherein the dispersion chamber has a characteristic dimension that is from 4 to 20 times greater than the characteristic dimension of the bead.  
   
   
       11 . An inhaler comprising: 
 a dispersion chamber having an open central interior region;    at least one bead in the dispersion chamber, with the dispersion chamber having a diameter or an interior characteristic dimension that is 4 to 20 times greater than a characteristic dimension of the largest bead in the dispersion chamber;    an inlet into the dispersion chamber;    an outlet in the dispersion chamber; and    a tubular mouthpiece oriented approximately perpendicular to the outlet.    
   
   
       12 . The inhaler of  claim 11  further comprising a single unit dose blister container supported on the inlet, and containing a single dose of a dry powder pharmaceutical.  
   
   
       13 . The inhaler of  claim 11  further comprising a plurality of beads in the chamber.