Patent ID: 6277099
Filing Date: 2001-08-21
Classification: A61M

Abstract:
A medication delivery pen, comprising:a housing having opposing proximal and distal ends;an actuator disposed in the proximal end of the housing for setting and administering a dosage of medication;a medication-containing cartridge assembly having a cartridge with a pierceably sealed distal end, an open proximal end removably attachable to the distal end of the housing, and a piston in sliding, fluid tight engagement within said cartridge;a drive mechanism coupled between the actuator and the cartridge to exert an axial force on the piston to inject the set dosage of medication, wherein the actuator triggers the drive mechanism to administer the injection of medication held in the cartridge;a processor coupled to the actuator to determine a value equal to the dosage set by the actuator; andmeans for disabling the processor when the cartridge is removed or not properly inserted in the housing,wherein the drive mechanism includes: a pair of half nuts in rotational engagement with the actuator; a non-rotatable lead screw having a proximal end, a distal end for exerting the axial force on the piston to inject the set dosage of medication, and a set of threads extending between the proximal and distal ends, said half nuts being radially openable and closable to selectively engage with the threads of the lead screw for axially advancing along the lead screw upon rotation of the actuator.