Therapeutic product delivery device
A therapeutic product delivery device is described which comprises a device body and a cartridge for holding a therapeutic product. An engagement structure is provided for releasably engaging the cartridge with the device body. A fault detector is provided for detecting a fault in the delivery of the therapeutic product from the cartridge. A release trigger is responsive to the detection of a fault to cause the engagement structure to release the cartridge from the device body. In this way, a fault causes the cartridge to be released from the device body, which will prevent any further delivery of the therapeutic product to the patient. This solution is strongly preferable to a solution in which a product delivery mechanism (e.g. a pump) is merely paused or stopped, since when the cartridge separates then no further delivery is possible at all, until the cartridge is reattached (or more probably replaced with a new cartridge in case the fault is with the cartridge).
1. A therapeutic product delivery device comprising:
a device body;
a cartridge for holding a therapeutic product;
an engagement structure for releasably engaging the cartridge with the device body the engagement structure comprising:
one or more first engaging elements on one or other of the device body and the cartridge, the first engaging elements being engagable with one or more corresponding second engaging elements on the other of the device body and the cartridge,
a releasing element which is moveable between a retaining position in which the first engaging elements are able to engage the second engaging elements, and a releasing position in which the first engaging elements are not able to engage with the second engaging elements, and
a wire element which is deformable in response to an applied electric current to move the releasing element from the retaining position to the releasing position;
a fault detector for detecting a fault in the delivery of the therapeutic product from the cartridge; and
a release trigger, responsive to the detection of a fault, to apply an electric current to the wire element, thereby deforming the wire element to cause the engagement structure to release the cartridge from the device body.
2. The therapeutic product delivery device according to claim 1 , wherein the cartridge comprises a reservoir containing the therapeutic product and a pumping device for pumping the therapeutic product from the reservoir to the patient.
3. The therapeutic product delivery device according to claim 2 , wherein
the device body comprises a biasing element which presses against the reservoir of the cartridge when the cartridge is engaged with the device body; and
the force exerted by the biasing element on the cartridge causes the cartridge to be ejected away from the device body when the engagement structure releases the cartridge from the device body.
4. The therapeutic product delivery device according to claim 3 , wherein the biasing element comprises a spring.
5. The therapeutic product delivery device according to claim 1 , wherein the first engaging elements are clips, and the second engaging elements are lugs.
6. The therapeutic product delivery device according to claim 1 , wherein the engagement structure comprises a spring which biases the releasing element towards the retaining position, the wire element acting against the bias in response to the applied electric current to move the releasing element into the releasing position.
7. The therapeutic product delivery device according to claim 1 , comprising a release actuator, responsive to user manipulation to move the releasing element from the retaining position to the releasing position.
8. The therapeutic product delivery device according to claim 1 , wherein the fault detector detects a fault when a rate of delivery of the therapeutic product exceeds a predetermined threshold rate.
9. The therapeutic product delivery device according to claim 3 , wherein the biasing element presses against a movable element of the reservoir, and the fault detector comprises a displacement sensor for detecting a position of the movable element and detection circuitry for detecting a fault when the position of the movable element changes at a rate above a predetermined threshold rate.