Optimizing release of dry medicament powder

Abstract

A method based on an Air-razor tool is disclosed thereby providing improved release and dispersal into air of a dose of medication powder. When air is sucked through a suction tube, particles of a powder dose, made available to the suction tube, are gradually released and dispersed into a stream of air entering the suction tube. The gradual release and dispersal is produced by a relative motion introduced between the suction tube and the dose. The high velocity air going into the suction tube inlet provides plenty of shearing stress and inertia energy as the flowing air hits the leading point of the dose. This powder Air-razor method, created by the shearing stress and inertia of the air stream, is so powerful that the particles of the powder adjacent to the inlet of the moving suction tube are released and subsequently entrained in the air stream going through the suction tube.

1 . A method of releasing and dispersing into an airstream a dose of dry powder, releasably retained onto a substrate member, comprising: 
 applying suction pressure to an outlet of a suction tube, said suction thereby creating an airstream through the suction tube from inlet to outlet;    introducing a relative motion between the suction tube and a substrate member, having a dry powder dose of a selected powder formulation thereon, within a time frame of a single suction effort, the inlet aperture of the suction tube being optimized for a release of said dose;    maintaining said suction pressure for the duration of said motion from beginning to end, such that the inlet aperture and the substrate member including the dose thereon traverse one another, whereby the motion and the airstream together provide sufficient shearing power onto the full volume of the dose by means of said motion, said shearing power releasing the powder of the dose from the substrate member and dispersing the powder dose into the airstream by creating a difference in external forces acting on dose particles that overcomes the adhesion and friction forces holding them together.    
   
   
       2 . The method according to  claim 1 , comprising the further step of 
 selecting a volumetric, gravimetric, electrostatic or electro-dynamic method of filling the dose, or a combination of such methods.    
   
   
       3 . The method according to  claim 1 , comprising the further step of 
 selecting an optimal position for said aperture adjacent to the substrate member at a first, selected distance from the substrate member and at a second, chosen distance from the dose on the substrate member.    
   
   
       4 . The method according to  claim 1 , comprising the further step of 
 traversing the substrate member by the suction tube inlet aperture or vice versa, at least partly, including the dose thereon, at least partly, whereby the powder of the dose is released, at least partly, from the substrate member and dispersed at least partly into the airstream.    
   
   
       5 . The method according to  claim 1 , comprising the further step of 
 providing, by the pre-defined suction pressure power, a shearing power adapted to the powder formulation, the dose mass and the physical dose volume, in an area adjacent to the inlet aperture of the suction tube, said shearing power preferably being applied to all parts of the dose gradually by means of the relative motion between the suction tube and the substrate member, or vice versa.    
   
   
       6 . The method according to  claim 5 , comprising the further step of 
 providing a level of shearing power that is able to release, at least partly, particles contained in the powder dose.    
   
   
       7 . The method according to  claim 1 , comprising the further step of 
 optimizing size and shape of the inlet aperture to be adapted to the properties of the powder formulation of the dose, the dose mass, and the physical dose volume;    arranging the relative motion of the inlet aperture to track at the selected distance the surface curvature of the substrate member, or vice versa, where the dose is present upon at least a part of said surface.    
   
   
       8 . The method according to  claim 7 , comprising the further step of 
 applying said Air-razor effect on a dose concentrated to a single spot on the substrate member, said dose filled using a method or methods according to  claim 2 .    
   
   
       9 . The method according to  claim 7 , comprising the further step of 
 applying said Air-razor effect on an extended or elongated dose on the substrate member, said dose filled using a method or methods according to  claim 2 .    
   
   
       10 . The method according to  claim 7 , comprising the further step of 
 applying said Air-razor effect on a dose comprising more than one deposit on the substrate member, said dose filled using a method or methods according to  claim 2 .    
   
   
       11 . The method according to  claim 7 , comprising the further step of 
 applying said Air-razor effect on a combined dose comprising at,least one deposition each of at least two different active ingredients on the substrate member, said combined dose filled using a method or methods according to  claim 2 .    
   
   
       12 . The method according to  claim 7 , comprising the further step of 
 applying said Air-razor effect on a single or a combined dose distributed at random on the substrate member, said dose filled using a method or methods according to  claim 2 .    
   
   
       13 . A method of optimizing emission of a dose of dry powder, releasably retained on a substrate member by use of an Air-razor method, comprising: 
 setting Air-razor parameters according to characteristics of the dose and the dry powder;    applying a pre-defined suction pressure to a mouthpiece in fluid connection with an outlet of a suction tube and moving the suction tube relative the substrate member, or vice versa;    maintaining said suction pressure for the duration of said motion from beginning to end, such that the inlet aperture and the substrate member and the dose thereon traverse one another, whereby the motion and the airstream together constitute an Air-razor effect that releases and disperses the powder dose into the airstream going through the mouthpiece into a receiver;    measuring the amount of retained powder on the substrate member and optionally in the suction tube and/or the mouthpiece and optionally measuring the fine particle fraction of the emitted dose;    comparing measurement results with previously determined requirements, and    repeating the method, if the measurement results are not satisfactory, using a revised set of Air-razor parameters, including first aperture size, shape, aperture distance to the substrate, duration of suction and speed and time of relative motion, until the results meet the requirements or the optimization process is stopped.    
   
   
       14 . The method according to  claim 13 , comprising the further step of 
 selecting a volumetric, gravimetric, electrostatic or electro-dynamic method of filling the dose, or a combination of such methods.    
   
   
       15 . The method according to  claim 13 , comprising the further step of 
 applying said Air-razor method on a dose concentrated to a spot on the substrate member, said dose filled using a method or methods according to  claim 14 .    
   
   
       16 . The method according to  claim 13 , comprising the further step of 
 applying said Air-razor method on an extended or elongated dose on the substrate member, said dose filled using a method or methods according to  claim 14 .    
   
   
       17 . The method according to  claim 13 , comprising the further step of 
 applying said Air-razor method on a dose comprising more than one deposit on the substrate member, said dose filled using a method or methods according to  claim 14 .    
   
   
       18 . The method according to  claim 13 , comprising the further step of 
 applying said Air-razor method on a combined dose comprising at least one deposition each of at least two different active ingredients on the substrate member, said dose filled using a method or methods according to  claim 14 .    
   
   
       19 . The method according to  claim 13 , comprising the further step of 
 applying said Air-razor method on a single or a combined dose distributed at random on the substrate member, said dose filled using a method or methods according to  claim 14 .    
   
   
       20 . The method according to  claim 13 , comprising the further step of 
 selecting the pre-defined suction pressure to be within a range from 2 to 4 kPa for the duration of said motion from beginning to end.    
   
   
       21 . The method according to  claim 1 , comprising the further step of 
 selecting the duration of said motion to be at least 0.2 s and less than 2 s from beginning to end.    
   
   
       22 . An optimized Air-razor device for releasing a dry powder medication dose from a substrate member and disperse the dose into an airflow, comprising: 
 a suction tube having an inlet aperture adapted to the dose and a larger outlet aperture;    said inlet aperture positioned adjacent to the substrate member    the suction tube and the substrate member being moveable in relation to one another;    said device comprising a controller for controlling the speed of motion suction tube-substrate member in relation to one another upon movement,    said device being optimized by setting Air-razor parameters according to characteristics of the dose and the dry powder;    applying a pre-defined suction pressure to a mouthpiece in fluid connection with an outlet of a suction tube and moving the suction tube relative the substrate member, or vice versa;    maintaining said suction pressure for the duration of said motion from beginning to end, such that the inlet aperture and the substrate member and the dose thereon traverse one another, whereby the motion and the airstream together constitute an Air-razor effect that releases and disperses the powder dose into the airstream going through the mouthpiece into a receiver;    measuring the amount of retained powder on the substrate member and optionally in the suction tube and/or the mouthpiece and optionally measuring the fine particle fraction of the emitted dose;    comparing measurement results with previously determined requirements, and    repeating the method, if the measurement results are not satisfactory, using a revised set of Air-razor parameters, including first aperture size, shape, aperture distance to the substrate, duration of suction and speed and time of relative motion, until the results meet the requirements or the optimization process is stopped.    
   
   
       23 . A dry powder inhaler device, wherein 
 the inhaler device comprises an optimized Air-razor device according to  claim 22.