Abstract: A hypodermic syringe with a selectively retractable includes an barrel having an proximal end and a distal end that defines a receiver with a shoulder. The barrel has a hollow bore therethrough and the receiver includes a plurality of inwardly projecting cams distal to the shoulder. There is an elongate plunger with a proximal end and a distal end sized to fit slidably within the bore of the barrel to define a chamber. There is a hub with a flange and a stem that has a passageway therethrough extending distally into the receiver. The stem has distal recesses disposed to engage the projecting cams so that the hub is retained with the distal end of the stem in the receiver. The syringe includes a needle mounted in the passageway in the hub with the distal point projecting distally and the fluid path communicates with the chamber. There is a clip about the elongate plunger initially allowing movement of the plunger for drawing and expelling fluid.

Abstract: A pen needle magazine dispenser for holding and dispensing a novel pen needle assembly. The pen needle magazine dispenser includes a number of threaded sleeves within cavities that interact with threads on each pen needle assembly to attach the pen needle to a special adapter on a conventional medication delivery pen. The magazine dispenser includes a sterility barrier and a cap to cover the pen needles.

Abstract: A pen needle magazine dispenser for holding and dispensing a novel pen needle assembly. The pen needle magazine dispenser includes a number of threaded sleeves within cavities that interact with threads on each pen needle assembly to attach the pen needle to a special adapter on a conventional medication delivery pen. The magazine dispenser includes a sterility barrier and a cap to cover the pen needles.

Abstract: A medication cartridge for use with a medication delivery pen having a cartridge body with threads at its distal end for receiving a pen-needle. The threads are either integrally molded in the cartridge or on the outer surface of a cap used to retain a septum on the distal end of the cartridge body. The cartridge body of the medication cartridge also includes threads or a snap-ring at its proximal end for attaching the medication cartridge directly to a pen body housing of the medication delivery pen without the need for a medication cartridge holder.

Abstract: An improved medication delivery pen is provided for injecting fluids such as insulin within body tissue. The medication delivery pen includes a mechanism that prevents the removal of a cartridge unless an injector button on the medication pen is in a predefined position, a bayonet attachment and an improved clutch assembly in a dose setting mechanism that provides improved control over the torque necessary to rotate a units counter ring in the medication delivery pen using a dose setting knob.

Abstract: An improved medication delivery pen is provided for injecting fluids such as insulin within body tissue. The medication delivery pen includes a mechanism that prevents the removal of a cartridge unless an injector button on the medication pen is in a predefined position, a bayonet attachment and an improved clutch assembly in a dose setting mechanism that provides improved control over the torque necessary to rotate a units counter ring in the medication delivery pen using a dose setting knob.