DRUG DELIVERY DEVICE Russian patent published in 2013 - IPC A61M5/24 A61M5/315 

FIELD: medicine.

SUBSTANCE: invention refers to medical equipment, namely to drug delivery devices wherein the user may load and measure a drug dose to be delivered from a repeated cartridge. A drug delivery device comprises a drug container, a dosage unit and a body integrating at least a portion of the dosage unit. The dosage unit comprises a piston rod movable in the distal direction for drug delivery, a drive moving the piston rod in the distal direction for drug delivery, a drug dose loading element and a dose limitation element preventing the drug dose load if the drug amount in the container is exceeded. The dose limitation element is axially movable in the proximal direction in relation to the piston rod when loading the dose. The dose limitation element comprises a first lock member. The piston rod comprises a second lock member. The first and second lock members are used to arrest the axial motion of the dose limitation element in the proximal direction in relation to the piston rod once the first and second lock members are engaged thereby arresting the motion of the drug dose loading element to increase the loaded drug dose to be delivered. The dose limitation element and the piston rod interact directly only once the first and second lock members are engaged. According to the second version of the drug delivery device, the dosage unit comprises at least one blocking element for blocking the dose loading element with the body, thereby preventing the dose loading element from rotation about the body to increase a dose. The blocking element is actuated once the first locking element of dose limitation with the second locking element of the piston rod, and a force is applied to the dose loading element to increase a dose. According to the third version of the drug delivery device, the piston rod comprises two threaded portions. The first threaded portion having no effect on the motion of the dose limitation element. The second threaded portion. One end of the thread of the second threaded portion forms the second lock member.

EFFECT: invention limits the dose loading reliably and precisely to correspond to a maximum amount of the drug; attaching a new cartridge requires no contact with any part of the dosage unit; easy replacement of the drug cartridge is provided almost without any force to a cartridge cap when re-setting the device and thereby without drug pressure increase inside the cartridge before the first loading and measuring have been completed.

36 cl, 3 dwg