Inhalers and Related Methods

Abstract

An inhaler ( 10 ) for the inhalation of inhalable substances comprise: a canister ( 50 ) having an interior reservoir ( 84 ) containing pressurised inhalable substances including fluid; a metering valve ( 52 ) including a metering chamber ( 82 ) and a valve stem ( 54 ) defining a communication path between the metering chamber and the interior reservoir, the communication path ( 86 ) including an opening ( 106 ) configured to permit flow between a transfer space inside the valve stem and the interior reservoir, the interior reservoir being arranged for orientation above the metering chamber whereby gas such as air located within the metering chamber is replaced with liquid from the interior reservoir.

What is claimed is: 
     
         1 . An inhaler for the inhalation of inhalable substances, the inhaler comprising: a canister having an interior reservoir containing pressurised inhalable substances including fluid;
 a metering valve including a metering chamber and a valve stem defining a communication path between the metering chamber and the interior reservoir, the communication path including an opening configured to permit flow between a transfer space inside the valve stem and the interior reservoir, the interior reservoir being arranged for orientation above the metering chamber whereby gas such as air located within the metering chamber is replaced with liquid from the interior reservoir.   
     
     
         2 . The inhaler of  claim 1 , in which the opening is configured to permit flow in a direction with an axial component along the valve stem directly between the transfer space inside the valve stem and the interior reservoir. 
     
     
         3 . The inhaler of  claim 1  in which the communication path is configured to permit liquid to flow under pressure along the communication path to the metering chamber and gas to flow in a reverse direction therealong from the metering chamber into the interior reservoir. 
     
     
         4 . The inhaler of  claim 1  in which the opening comprises an elongated opening. 
     
     
         5 . The inhaler of  claim 4  which includes a second opening or further openings into the communication path. 
     
     
         6 . The inhaler of  claim 5  in which the second opening is diametrically opposed to the first said opening. 
     
     
         7 . The inhaler of  claim 1  in which the valve stem has at least one opening into the interior reservoir with an axially oriented portion facing directly axially along a longitudinal axis of the valve stem into the interior reservoir for the flow of fluid directly into the communication path in an axial direction along the valve stem. 
     
     
         8 . The inhaler of  claim 1  which includes a metering chamber exit port for venting the metering chamber to atmosphere via a stem block and/or nozzle. 
     
     
         9 . The inhaler of  claim 1 , which includes a canister fire system for ejecting inhalable substances from the inhaler in response to air flow by closing communication between the metering chamber and the interior reservoir and opening communication between the metering chamber and atmosphere. 
     
     
         10 . The inhaler of  claim 9  which includes a drive for driving the canister relative to the valve stem, the drive optionally including a drive spring. 
     
     
         11 . The inhaler of  claim 10  which includes an actuator system for operating the drive, optionally in which the actuator system is actuatable by air flow. 
     
     
         12 . The inhaler of  claim 9  in which the canister fire system is adapted to depress the valve stem into the canister to cause inhalable substances to be ejected from the inhaler and to hold the valve stem depressed with the metering chamber communicating with atmosphere. 
     
     
         13 . The inhaler of  claim 12  in which the canister fire system includes a reset actuator which is operable so as to extend the valve stem relative to the canister in order to close communication between atmosphere and the metering chamber and to open communication between the metering chamber and the interior reservoir. 
     
     
         14 . The inhaler of  claim 13  in which the reset actuator comprises a mouthpiece cap for a mouthpiece of the inhaler, the mouthpiece cap being closable to permit extension of the valve stem relative to the canister, the mouthpiece cap optionally being hingedly connected to a main housing of the inhaler for camming engagement with at least one drive rod. 
     
     
         15 . The inhaler of  claim 14  which includes a preventer adapted, after an inhalation has taken place, to prevent a further inhalation until the mouthpiece cap has been closed to extend the valve stem. 
     
     
         16 . The inhaler of  claim 1 , wherein the inhalable substances comprise at least one propellant. 
     
     
         17 . The inhaler of  claim 16  in which at least one said propellant has a surface tension at 25° C. of about 6 to 10 mN/m. 
     
     
         18 . The inhaler of  claim 1 , wherein the inhalable substances comprise an active ingredient selected from the group consisting of beclomethasone dipropionate and tiotropium bromide. 
     
     
         19 . The inhaler of  claim 1  which includes a dose counter for counting doses. 
     
     
         20 . The inhaler of  claim 19  in which the dose counter includes: (a) a tape bearing dose indicia for displaying counts and/or (b) an actuator pin for contact with the canister, or a body movable therewith, for counting doses, and a dose counter chamber separated by a barrier from an inner space of the inhaler for containing the canister, the actuator pin extending out of the dose counter chamber through an aperture in the wall for contact during counting with the canister or the body movable therewith. 
     
     
         21 . The inhaler of  claim 1  which is a breath actuated inhaler. 
     
     
         22 . The inhaler of  claim 1  which is a metered dose inhaler. 
     
     
         23 . The inhaler of  claim 1  which is an oral inhaler. 
     
     
         24 . The inhaler of  claim 1  which is a nasal inhaler. 
     
     
         25 . The inhaler of  claim 1  which includes a reset actuator which when actuated prevents exposure of the metering chamber to atmosphere, wherein the inhaler provides 75 to 125% of labelled claim for a dose following exposure of the metering chamber to atmosphere for a time period which is more than one minute. 
     
     
         26 . The inhaler of  claim 25  in which the reset actuator is a mouthpiece cap that, when closed, prevents exposure of the metering chamber to atmosphere. 
     
     
         27 . The inhaler of  claim 25  in which the inhaler provides 75 to 125% of labelled claim for a dose following exposure of the metering chamber to atmosphere for a time period which is more than two minutes. 
     
     
         28 . The inhaler of  claim 25  in which the inhaler provides 75 to 125% of labelled claim for a dose following exposure of the metering chamber to atmosphere for a time period which is one hour, more than one hour, 24 hours or more than 24 hours. 
     
     
         29 . The inhaler of  claim 1  which includes a metering valve spring and an opposing canister spring for drivingly firing the canister, the metering valve spring, canister spring and metering valve being arranged in the inhaler such that an equilibrium of forces is achieved in at least one ready-to-fire configuration of the inhaler. 
     
     
         30 . The inhaler of  claim 29  which is adapted to operate including at least one suction force; the suction force operating against the canister spring.