Feeding Chamber, an Apparatus and a Method for Production of Doses of Dry Powder, a Method for Controlling Particle Segregation in Dry Powder During Filling

Abstract

A method and an apparatus for exact metering and volumetric filling of dry powder medicament doses into preformed containers, which are adapted for administration by a dry powder inhaler. The filling apparatus includes at least a bulk powder source, a feeding chamber, and a receptacle providing the volume for a specified load mass of dry powder. The bulk powder source releases a portion of powder discontinuously to the feeding chamber, but is disconnected from the feeding chamber and receptacle during the filling operation. The filling apparatus further presents a plane surface in contact with the movable feeding chamber and provides a hard-wearing, low friction coating for reducing dynamic friction and powder retention.

1 - 24 . (canceled) 
   
   
       25 . An apparatus for transporting dry powder from an external bulk powder source to a dose filling tool during volumetric filling of metered doses, the apparatus comprising:
 a feeding chamber device having at least one inlet adapted for receiving portions of dry powder from the external bulk powder source and at least one outlet adapted for dispensing powder to the dose filling tool;   an internal volume of the feeding chamber device is configured to hold a limited amount of powder representing a limited number of doses, and the feeding chamber device is configured to be replenished intermittently with powder from the external bulk powder source for maintaining a level of powder in the internal volume within specified limits over plural cycles of volumetric dose filling;   the feeding chamber device and the dose filling tool are arranged to be movable in relation to each other while the at least one outlet of the feeding chamber device is forcibly in contact with a surface of the dose filling tool during the relative movement, the relative movement providing shearing and frictional forces on a pillar of powder in the internal volume of the feeding chamber device, thereby assisting in providing a coherent plug of powder within the feeding chamber device; and   the feeding chamber device constitutes an independent, intermediate device, separating the bulk powder source from the dose filling tool.   
   
   
       26 . The apparatus according to  claim 25 , wherein
 the feeding chamber device comprises at least one energizable member, when energized capable of collapsing a body of powder in the feeding chamber device into a homogeneous plug of powder and separating the plug of powder from having generally contact with the inner surface of the feeding chamber device.   
   
   
       27 . The apparatus according to  claim 26 , wherein
 the energizable member comprises at least one scraper member movable relative to the feeding chamber device.   
   
   
       28 . An apparatus for volumetric production of doses of dry powder, the apparatus comprising:
 a bulk powder source containing the powder and comprising means for releasing portions of the powder;   a feeding chamber device comprising at least one inlet adapted for receiving portions of powder from the bulk powder source and at least one outlet adapted for dispensing powder to at least one powder metering receptacle of a dose filling tool;   the dose filling tool and the at least one outlet of the feeding chamber device are arranged for being movable in relation to each other such that the at least one outlet of the feeding chamber device is forcibly in contact with a surface of the dose filling tool during the relative movement; and   air suction means adapted for applying air suction power to fill the at least one metering receptacle with a dose of the powder when the at least one outlet of the feeding chamber device crosses the at least one metering receptacle during the relative movement,   wherein the feeding chamber device constitutes an independent, intermediate device, separating the bulk powder source from the dose filling tool.   
   
   
       29 . The apparatus according to  claim 28 , wherein
 the surface of the dose filling tool comprising the at least one metering receptacle is plane.   
   
   
       30 . The apparatus according to  claim 28 , wherein
 a filter is applied to the at least one metering receptacle such that powder particles are not lost to air being sucked during filling of the at least one metering receptacle.   
   
   
       31 . The apparatus according to  claim 30 , wherein
 the filter is a woven filter.   
   
   
       32 . The apparatus according to  claim 28 , wherein
 mechanical strength of the filter is re-enforced by arranging at least one of a supporting wire netting at one or both sides of the filter or a supporting sintered filter at one or both sides of the filter.   
   
   
       33 . The apparatus according to  claim 28 , wherein
 a spring force is applied to keep contact pressure between an air nozzle, the filter, and an opening of the at least one metering receptacle for sucking air, such that elastic seals sealing the nozzle, the filter, and at least one metering receptacle stops leakage of air and powder into and out of the at least one metering receptacle.   
   
   
       34 . The apparatus according to  claim 28 , wherein
 a source of electric charges is arranged in an air gap between the dose filling tool and a dose container, such that electrically charged particles in an ejected powder load become electrically neutralized while being transferred from at least one metering receptacle to the dose container.   
   
   
       35 . The apparatus according to  claim 28 , wherein
 sources of electric charges are arranged at a working distance to the bulk powder source or at a working distance to the powder in the feeding chamber device and to the dose filling tool to electrically neutralize electrostatic charges of the powder and the apparatus.   
   
   
       36 . The apparatus according to  claim 28 , further comprising:
 air pressure means for applying air pressure power to eject a metered dose of powder from the at least one metering receptacle when the receptacle is in a position for emptying into a dose container.   
   
   
       37 . A method of transporting dry powder from an external bulk powder source to a dose filling tool during volumetric filling of metered doses, comprising:
 intermittently feeding a portion of powder from the external bulk powder source to a feeding chamber device through at least one inlet of the feeding chamber device, the feeding chamber device configured to contain a limited amount of powder representing a limited number of doses, and comprising at least one outlet adapted for dispensing powder to the dose filling tool; and   providing a relative movement between the feeding chamber device and the dose filling tool while the at least one outlet of the feeding chamber device is in forcible contact with a surface of the dose filling tool during the relative movement, the relative movement providing shearing and frictional forces on a pillar of powder in the feeding chamber device, thereby assisting in providing a coherent plug of powder within the feeding chamber device,   wherein the feeding chamber device constitutes an independent, intermediate device, separating the external bulk powder source from the dose filling tool and transporting the dry powder from the external bulk powder source to the dose filling tool.   
   
   
       38 . The method according to  claim 37 , further comprising:
 energizing at least one energizable member in the feeding chamber device, which when energized is capable of collapsing a body of powder in the feeding chamber device into a homogeneous plug of powder and generally separating the body of powder from having contact with the inner surface of the feeding chamber device.   
   
   
       39 . The method according to  claim 38 , wherein
 the at least one energizable member comprises at least one scraper member movable relative the inside of the feeding chamber device.   
   
   
       40 . A method of producing volumetric doses of dry powder, comprising:
 intermittently replenishing as required a portion of powder from a bulk powder source to at least one inlet of a feeding chamber device;   providing a relative movement between the feeding chamber device and a dose filling tool comprising at least one powder metering receptacle such that at least one outlet of the feeding chamber device crosses the at least one metering receptacle in such a way that the at least one outlet is in forcible contact with a surface of the dose filling tool; and   applying air suction power to fill the at least one metering receptacle with a dose of the powder from the feeding chamber device when the at least one outlet of the feeding chamber device crosses the at least one metering receptacle,   wherein the feeding chamber device constitutes an independent, intermediate device, separating the bulk powder source from the dose filling tool and the applied air suction to the metering receptacle.   
   
   
       41 . The method according to  claim 40 , wherein
 the surface of the filling tool is plane.   
   
   
       42 . The method according to  claim 40 , further comprising:
 applying a filter to the at least one metering receptacle such that powder particles are not lost to air being sucked during filling of the receptacle.   
   
   
       43 . The method according to  claim 40 , further comprising:
 re-enforcing mechanical strength of the filter by arranging at least one of a supporting wire netting at one or both sides of the filter or a supporting sintered filter at one or both sides of the filter.   
   
   
       44 . The method according to  claim 40 , further comprising:
 applying a spring force to obtain contact pressure between an air nozzle, the filter, and an opening of the at least one metering receptacle for sucking air, such that elastic seals sealing the nozzle, the filter, and the at least one metering receptacle stops leakage of air and powder into and out of the receptacle.   
   
   
       45 . The method according to  claim 40 , further comprising:
 arranging a source of electric charges in an air gap between the filling tool and a dose container, such that electrically charged particles in an ejected powder load become electrically neutralized while being transferred from the at least one metering receptacle to the dose container.   
   
   
       46 . The method according to  claim 40 , further comprising:
 arranging sources of electric charges at a working distance to the bulk powder source or at a working distance to the powder in the feeding chamber and to the filling tool to accomplish that electrostatic charges of the powder and the apparatus become electrically neutralized such that the filling process is not adversely affected.   
   
   
       47 . The method according to  claim 40 , further comprising:
 applying air pressure powder to eject a metered dose of powder from the at least one metering receptacle when the receptacle is in a position for emptying into a dose container.   
   
   
       48 . The method according to  claim 40 , wherein
 a mass target of the doses is in a range of 100 μg-50 mg, or in a range of 100 μg-10 mg, or in a range of 100 μg-5 mg.