Dry powder inhaler with reproducible flow resistance
Inventors
Ahern, David • Danson, Arron • Tibatts, James • Christie, Ewen • Evans, Tim
Assignees
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Publication Number
US-11020549-B2
Publication Date
2021-06-01
Expiration Date
Abstract
A dry powder inhalation device is disclosed. In one optional aspect, the device includes a housing, a base plate, a receptacle for a medicament and a mouthpiece. The base plate is engageable with the housing to form a main space with a main air inlet. The mouthpiece includes an inner conduit connected to its outlet and is engageable with the base plate to fluidly connect the inner conduit to the receptacle. The receptacle is fluidly connected to the main space, so that upon inhalation by a user, air can be drawn through the main air inlet into the main space and onward through the receptacle into the inner conduit. The mouthpiece and the base plate form an auxiliary space with an auxiliary air inlet, wherein the auxiliary space is fluidly connected to the main space.
Core Innovation
The invention relates to a dry powder inhalation device that achieves reproducible flow resistance during inhalation. The device includes a housing, a base plate, a receptacle for a medicament, and a mouthpiece, where the base plate is engageable with the housing to form a main space with a main air inlet. The mouthpiece has an inner conduit connected to its outlet and is engageable with the base plate so the inner conduit is fluidly connected to the receptacle, with the receptacle fluidly connected to the main space.
During inhalation by a user, air is drawn through the main air inlet into the main space, onward through the receptacle into the inner conduit. The mouthpiece and the base plate form an auxiliary space with an auxiliary air inlet, and the auxiliary space is fluidly connected to the main space through at least one air exchange opening in the base plate. Flow resistance of each of the main air inlet and the auxiliary air inlet is constrained to be lower than the flow resistance of a path between the main space and the mouthpiece outlet and also lower than the flow resistance of a path between the auxiliary space and the mouthpiece outlet.
The device further addresses batch-to-batch variability caused by manufacturing leakage paths by providing a bypass air path between the auxiliary space and the mouthpiece inner conduit. The bypass air path is formed by cooperative openings or recesses between a portion of a hole formed in the base plate and a portion of a hole formed in the screen holder, and its flow resistance is taught to be sufficiently constant and preferably lower than leakage-path combined resistance.
Claims Coverage
The independent claims cover three inventive aspects: a main space with a main air inlet plus an auxiliary space with an auxiliary air inlet connected to the main space and to the mouthpiece via a bypass architecture, with constrained flow-resistance relationships; a bypass air path defined by cooperative hole portions between the base plate and a screen holder; and a separation of bypass and air-exchange opening geometry such that the air exchange opening(s) differ in shape and/or size from a bypass opening.
Main and auxiliary spaces with constrained inlet flow resistances
A dry powder inhalation device where the mouthpiece and base plate form an auxiliary space with an auxiliary air inlet fluidly connected to the main space via at least one air exchange opening, and where flow resistance of each of the main air inlet and the auxiliary air inlet is lower than the flow resistance of paths between each space and the mouthpiece outlet.
Bypass air path formed by cooperative hole portions
A device where the auxiliary space is fluidly connected to the inner conduit by a bypass air path, the bypass air path being formed by cooperation between a portion of a hole formed in the base plate and a portion of a hole formed in the screen holder.
Air exchange opening(s) geometrically differ from bypass opening
A device where the auxiliary space is fluidly connected to the inner conduit by a bypass air path having a bypass opening, and where the at least one air exchange opening is at least one of a different shape and a different size than the bypass opening.
Across the independent claims, the inventive coverage centers on forming a main and auxiliary flow architecture with an air-exchange opening to connect auxiliary to main space, imposing flow-resistance relationships so main and auxiliary inlet resistances are lower than paths to the mouthpiece outlet, and defining a bypass air path to the inner conduit via cooperative hole structures, with air-exchange opening geometry differing from a bypass opening.
Stated Advantages
Reproducible flow resistance during user inhalation.
Reduction of dose variability caused by hand-holding altering which inlet is obstructed, by constraining the flow-resistance relationships so the remaining inlet is not limiting.
Improved batch-to-batch consistency by addressing manufacturing leakage paths using a bypass air path with sufficiently constant flow resistance, preferably lower than leakage-path combined resistance.
Time-averaged resistance behavior is supported by the bypass air path in the presence of capsule shuttling that affects flow resistance over time.
Documented Applications
Dry powder inhalation using a device having a mouthpiece, receptacle for a medicament, main and auxiliary spaces, and a bypass air path to manage flow resistance during inhalation by a user.
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