Inhalers and Related Methods

Abstract

An inhaler housing (14) for an inhaler (10) for inhaling inhalable substances, the inhaler having: a body (14) and a dose counter (24) with a return spring (28), wherein a distinct guide surface (162) is provided for guiding the end of the return spring into a recess (152), the distinct guide surface being wider than an entrance mouth (160) of the recess, a dose counter chamber (22) being provided which is separated from a tubular interior space (182) of the inhaler by a barrier (180), the barrier including a stepped upper wall area (184) including at least three steps (186, 188, 190, 192) at different levels, the inhaler having a valve stem block (62) having an inner bore and a valve stem block having a seal (224) in the inner bore with a second diameter which is smaller than a first diameter of the inner bore, the inhaler having a canister (150) being adapted to move during operation between 1 and 4 mm, a drive being arranged to apply a firing force of between 15N and 60N of force to the canister at a position of the canister relative to a valve stem (54) at which the canister fires.

What is claimed is: 
     
         1 . An inhaler housing for an inhaler for inhalable substances, the inhaler housing being arranged to contain a pressurised canister for sliding motion within a tubular body portion thereof, the inhaler housing having a valve stem block for connection to a valve stem of a pressurised canister, the valve stem block having a top surface, the tubular body portion having at least two mutually opposed guide ribs for guiding canister position within the tubular body portion, the guide ribs having substantially straight guide edges extending substantially parallel to and spaced from one another, each straight guide edge having an upper corner where the straight guide edge meets a further surface of the rib leading outwardly towards an upper rib section near an inner wall of the tubular body portion, at least one of the ribs having its straight guide edge's upper corner positioned a distance D 2  in a direction parallel to an axis of the valve stem block along away from the top surface of the valve stem block, a distance between the straight guide edges of the ribs perpendicular to the axis being ID 2 , and in which the ratio D 2 /ID 2  is less than 0.8. 
     
     
         2 . The inhaler housing of  claim 1  in which the ratio D 2 /ID 2  is less than 0.75, about 0.7 being one example. 
     
     
         3 . The inhaler housing of  claim 1  in which the further surface of at least one guide rib extends away from the valve stem block and terminates at a distance D 3  from the top surface of the valve stem block in the direction parallel to the axis, the ratio D 3 /ID 2  being less than 0.9 or less than 0.85, about 0.8 being one example. 
     
     
         4 . The inhaler housing of  claim 1  in which each guide rib meets the upper rib section near the inner wall of the tubular body portion at outer rib positions wherein the outer rib positions are a distance ID 1  apart in a direction perpendicular to the axis, and in which the ratio ID 2 /ID 1  is between 0.7 and 0.9, typically between 0.75 and 0.85, about 0.78 or 0.8 being two examples. 
     
     
         5 . An inhaler housing for an inhaler for inhaling inhalable substances, the inhaler having: a body and a dose counter with an actuation member adapted to drive a dose indication portion of the dose counter against a return spring, the body including a recess for location of an end of the return spring; the recess having a substantially flat reaction surface, a shoulder surface adjacent the reaction surface and an entrance mouth into the reaction surface; wherein a distinct guide surface is provided for guiding the end of the return spring into the recess, the distinct guide surface being wider than the entrance mouth in a direction across the mouth. 
     
     
         6 . The inhaler housing of  claim 5  in which the entrance mouth has at least one chamfered entrance lip, the distinct guide surface having a slanted edge which is an extension of the lip. 
     
     
         7 . The inhaler housing of  claim 5  in which the distinct guide surface is substantially coplanar. 
     
     
         8 . The inhaler housing of  claim 5  in which at least a portion of the distinct guide surface comprises a portion of the body which is recessed relative to an adjacent portion of the body. 
     
     
         9 . An inhaler housing for an inhaler for inhaling inhalable substances, the inhaler housing having a tubular portion defining a tubular interior space for containing a pressurised canister containing inhaler substances, a valve stem block for engagement with a valve stem of such a pressurised canister, and a dose counter chamber for containing a dose counter assembly, the dose counter chamber being separated from the tubular interior space by a barrier, the barrier including a stepped upper wall area including at least three steps at different levels. 
     
     
         10 . The inhaler housing of  claim 9  which includes four said steps. 
     
     
         11 . The inhaler housing of  claim 9  in which the steps are arcuate. 
     
     
         12 . The inhaler housing of  claim 11  in which the arcuate steps have substantially flat areas aligned substantially perpendicular to an axis of the valve stem block as well as part-cylindrical riser surfaces between the substantially flat areas. 
     
     
         13 . The inhaler housing of  claim 11  in which the steps are substantially concentric with an axis of the valve stem block. 
     
     
         14 . The inhaler housing of  claim 11  in which the steps extend around the valve stem block a distance of about 180 degrees. 
     
     
         15 . The inhaler housing of  claim 11  in which the material forming the barrier is of substantially constant thickness substantially throughout the steps. 
     
     
         16 . The inhaler housing of  claim 11  in which the dose counter chamber is formed with at least one heat staking pin for mounting of a dose counter system, the heat staking pin being directly attached to at least two of the steps. 
     
     
         17 . The inhaler housing as claimed in  claim 16  in which the heat staking pin is attached to at least one step surface that is oriented substantially perpendicular to an axis of the valve stem block and to at least one and preferably two step risers. 
     
     
         18 . The inhaler housing of  claim 1  in which an aperture for a drive pin for actuating the dose counter is formed through a second furthest step away from the valve stem block. 
     
     
         19 . An apparatus comprising an inhaler valve stem and valve stem block interface for a breath actuated inhaler having a dose counter and a pressurised canister containing inhaler substances including a medicament, which may be in suspension or in solution, the valve stem block having a cylindrical inner bore with an inner diameter which is a first diameter, the cylindrical inner bore being for accepting a valve stem with an outer diameter, the valve stem block having a seal in the inner bore with a second diameter which is smaller than the first diameter. 
     
     
         20 . The apparatus of  claim 19  in which the first diameter is about 3.22 mm. 
     
     
         21 . The apparatus of  claim 19  in which the first diameter is about 3.5% larger than the second diameter. 
     
     
         22 . The apparatus of  claim 19  in which an outer diameter of the valve stem is smaller than the first diameter but larger than the second diameter prior to introduction of the valve stem into the inner bore, preferably about 0.75% to 1.5% larger, for example about 1% larger. 
     
     
         23 . The apparatus of  claim 19  in which the valve stem block includes an annular recess concentric with and extending around the inner bore at least partially around the circumference thereof, the inner diameter of the annular recess being about 25 to 50% larger than the inner diameter of the cylindrical inner bore, for example about 40% larger. 
     
     
         24 . A breath actuated inhaler having a drive adapted to drive a pressurised canister so as to retract a metering valve stem into the canister to fire the canister, the canister being adapted to move during operation between 1 and 4 mm between end positions of its length of travel relative to the valve stem, the drive being arranged to apply a firing force of between 15N and 60N of force to the canister at a position of the canister relative to the valve stem at which the canister fires. 
     
     
         25 . The breath actuated inhaler of  claim 24  in which the drive comprises a drive spring. 
     
     
         26 . The breath actuated inhaler of  claim 24  in which the canister is arranged to move between 1 and 3 mm between the end positions, for example 3 mm. 
     
     
         27 . The breath actuated inhaler of  claim 24  in which the drive is adapted to provide the firing force as more than 25N, preferably also less than 60N. 
     
     
         28 . The breath actuated inhaler of  claim 24  in which the firing force is more than 35N or equal to that required to fire the canister. 
     
     
         29 . The breath actuated inhaler of  claim 24  in which the firing force is greater than the sum at the point of firing of opposing forces applied to the canister by a valve stem spring in the canister and a return spring for an actuator pin of a dose counter of the inhaler. 
     
     
         30 . An inhaler including the inhaler housing of  claim 1 . 
     
     
         31 . A method of treating a respiratory disease or disorder comprising actuating the inhaler of  claim 24  to administer a therapeutically effective amount of one or more active ingredients. 
     
     
         32 . The method of  claim 31 , wherein the inhaler is a breath-actuated inhaler and the step of actuating the inhaler comprises inhaling through the inhaler. 
     
     
         33 . The method of  claim 31 , wherein the respiratory disease or disorder is asthma. 
     
     
         34 . The method of  claim 31 , wherein the respiratory disease or disorder is COPD. 
     
     
         35 . The method of  claim 31 , wherein the one or more active ingredients comprise a corticosteroid. 
     
     
         36 . The method of  claim 31 , wherein the one or more active ingredients comprise beclomethasone dipropionate or tiotropium bromide.