Medicament delivery device with cartridge sensor and cartridge holder door sensor and method of controlling the device

1. A medicament delivery device for the administration of one or more drug agents, wherein the device comprises:

a retainer for holding a medicament cartridge, the retainer being moveable between an open and closed position;

a position sensor for generating a position output indicative of whether the retainer is in an open or closed position;

a cartridge sensor for generating a cartridge output indicative of whether the retainer is holding a medicament cartridge;

a piston rod and drive train;

a controller for controlling a predetermined operation of the device in dependence on an output of the position sensor and on an output of the cartridge sensor;

a dispense interface for providing fluidic communication between an outlet and a medicament cartridge retainer;

an interface sensor for generating an output indicative of whether the dispense interface is attached to or detached from the device;

a latch movable under control of the controller between a latched position, for holding the retainer in said closed position, and an unlatched position, for allowing opening of the retainer to the open position; and

a cartridge door button;

the controller being operative for controlling a predetermined operation of the device in dependence on an output of the interface sensor, wherein the predetermined operation relates to a cartridge change cycle of the device upon detachment of the dispense interface,

wherein, in response to receiving an output from the interface sensor indicating that the dispense interface is detached from the device, the controller is configured to initiate the cartridge change cycle,

wherein initiating the cartridge change cycle comprises:

activating said cartridge door button; and

in response to detecting that the activated cartridge door button has been actuated by a user, retracting the piston rod from the medicament cartridge and moving the latch from the latched position to the unlatched position.

2. A medicament delivery device according to claim 1 , wherein the controller facilitates control of different predetermined operational sequences depending on the outputs from the cartridge and position sensors.

3. A medicament delivery device according to claim 2 , wherein a first predetermined operational sequence is implemented by the controller when the cartridge sensor indicates that the retainer is holding a medicament cartridge and the position sensor indicates that the retainer is in a closed position, and the first one of said predetermined operational sequences includes advancing the piston rod to the medicament cartridge.

4. A medicament delivery device according to claims 2 , wherein a second predetermined operational sequence is implemented by the controller when the cartridge sensor indicates that the retainer is not holding a medicament cartridge and the position sensor indicates that the retainer is in a closed position, and wherein the second predetermined operational sequence includes displaying a prompt to insert a cartridge in the device.

5. A medicament delivery device according to claim 1 , wherein the device is hand-held.

6. A medicament delivery device according to claim 5 , wherein the device is a pen-type injection device.

7. A medicament delivery device according to claim 1 comprising first and second retainers each for holding a medicament cartridge.

8. A method of controlling a medicament delivery device having a dispense interface, comprising: sensing detachment of the dispense interface from the device; activating a cartridge door button in response to sensing detachment of the dispense interface from the device; sensing actuation of the activated cartridge door button in response to the sensed detachment of the dispense interface and retracting a piston rod from a medicament cartridge retainer of the device in response thereto; opening the medicament cartridge retainer following retraction of the piston rod; sensing outputs of a cartridge sensor and a medicament cartridge retainer position sensor; and either advancing the piston rod towards the medicament cartridge when the output of the cartridge sensor indicates the presence of a cartridge and the output of the medicament cartridge retainer position sensor indicates the retainer is in a closed position, or prompting insertion of a medicament cartridge when the output of the cartridge sensor does not indicate the presence of a cartridge when the position sensor indicates that the retainer is in the closed position.