Pen needle magazine

1. An attachable needle assembly for use on a medication delivery pen, the needle assembly comprising:

a housing enclosing:

a hub being fixed to a communication needle, the hub being configured to engage the medication delivery pen and the communication needle being configured to pierce a reservoir septum of the medication delivery pen;

a communication septum of the needle assembly defining a septum chamber, the septum chamber of the needle assembly being in continuous fluid communication with the communication needle;

a plurality of needles disposed in the communication septum of the needle assembly;

a follower ring that rotates and identifies which needle of the plurality of needles is to be selected; and

a snap ring that applies a force to expose the selected needle and move the selected needle to be in fluid communication with the septum chamber of the communication septum of the needle assembly, wherein

when the housing is in a first position, the plurality of needles is not exposed, and when the housing is in a second position, the selected needle of the plurality of needles is in fluid communication with the septum chamber of the communication septum of the needle assembly and exposed for medicament delivery.

2. The attachable needle assembly of claim 1 , wherein the communication septum of the needle assembly includes an inner septum and an outer septum, the inner septum is sealed within the outer septum.

3. The attachable needle assembly of claim 2 , wherein the inner septum includes the septum chamber, the septum chamber comprising a circular cavity and a longitudinal cavity that carries medicament from the communication needle and fluidly communicates with the selected needle of the plurality of needles in the second position.

4. The attachable needle assembly of claim 2 , wherein in the first position, each of a proximal end of the plurality of needles is disposed in the inner septum and each of a distal end of the plurality of needles is disposed in a sealing septum.

5. The attachable needle assembly of claim 2 , wherein in the second position, a proximal end of each of a remaining plurality of needles is disposed in the inner septum.

6. The attachable needle assembly of claim 1 , wherein in the second position, a proximal end of the selected needle of the plurality of needles is in fluid communication with the septum chamber.

7. The attachable needle assembly of claim 1 , wherein

each of the plurality of needles is secured in a respective needle post; and

the snap ring includes a flange that contacts and moves one of the plurality of needle posts to expose a distal end of the selected needle when the housing is in the second position.

8. The attachable needle assembly of claim 1 , wherein the follower ring includes an opening that mates with a flange of the snap ring.

9. The attachable needle assembly of claim 1 , further comprising

a guiding post that orients a plurality of needle posts; and

the plurality of needle posts each include an extending portion, wherein

the guiding post arranges the plurality of needle posts such that the extending portions extend outward from a centerline of the guiding post.

10. The attachable needle assembly of claim 1 , wherein the follower ring rotates with respect to the housing and moves axially with the housing when the housing travels between the first position and the second position.

11. The attachable needle assembly of claim 1 , further comprising a tactile ring that engages a septum housing and the housing to ensure that the follower ring axially moves with respect to the housing.

12. The attachable needle assembly of claim 1 , wherein

the follower ring includes two tooth shaped followers;

the plurality of needles are disposed in a guiding post, the guiding post is fixed to a bottom guide having a plurality of external fins; and

the communication septum is disposed in a septum housing having a plurality of external ridges, wherein

the tooth shaped followers of the follower ring contact the plurality of external fins of the bottom guide and the plurality of external ridges of the septum housing to rotate the follower ring.

13. The attachable needle assembly of claim 12 , wherein the tooth shaped followers alternate contact with the plurality of external fins of the bottom guide and the plurality of external ridges of the septum housing to rotate and select each needle consecutively from a first needle to a last needle of the plurality of needles.

14. The attachable needle assembly of claim 12 , wherein when the housing is moving from the first position to the second position, one of the two tooth shaped followers contacts one of the plurality of external fins of the bottom guide and causes the follower ring to rotate.

15. The attachable needle assembly of claim 12 , wherein when the housing is moving from the second position to the first position, one of the two tooth shaped followers contacts one of the plurality of external ridges of the septum housing and causes the follower ring to rotate.

16. The attachable needle assembly of claim 12 , wherein the housing is configured to move from the first position to the second position for each of the plurality of needles.

17. The attachable needle assembly of claim 1 , wherein each of the plurality of needles is configured for single use.

18. The attachable needle assembly of claim 1 , wherein the follower ring includes two tooth shaped followers and the two tooth shaped followers are circumferentially offset from each other on an internal surface of the follower ring.

19. The attachable needle assembly of claim 1 , further comprising

a sealing septum of the needle assembly that seals and maintains a sterile environment for the plurality of needles, wherein

when the housing is in the first position, a distal end of each of the plurality of needles is disposed in the sealing septum of the needle assembly.

20. The attachable needle assembly of claim 1 , wherein when the housing is in the second position, a distal end of each of a remaining plurality of needles is disposed in a sealing septum of the needle assembly.

21. The attachable needle assembly of claim 1 , wherein when the housing is in the second position, a distal end of the selected needle of the plurality of needles pierces a sealing septum of the needle assembly and is exposed.

22. The attachable needle assembly of claim 1 , wherein the plurality of needles includes at least seven needles.

23. The attachable needle assembly of claim 1 , wherein the plurality of needles do not pierce the reservoir septum of the medication delivery pen.

24. The attachable needle assembly a claim 1 , wherein the plurality of needles only move axially, do not substantially move radially and do not substantially rotate.

25. The attachable needle assembly of claim 1 , further including a cap connected to the housing that applies a force to the snap ring when the housing is moving from the second position to the first position.

26. The attachable needle assembly of claim 1 , further including

a cover enclosing the needle assembly; and

a label sealing and maintaining sterility of the needle assembly in the cover prior to operating with the medication delivery pen.

27. The attachable needle assembly of claim 1 , further including a plurality of indicators that identify a plurality of needle exposure lengths when the housing is moving from the first position to the second position.

28. The attachable needle assembly of claim 27 , wherein the plurality of indicators is disposed under the housing and is not visible in the first position.

29. The attachable needle assembly of claim 1 , wherein a plurality of needle numbers is sequentially disposed on an outer surface of the snap ring to indicate a number of the plurality of needles available for use.

30. The attachable needle assembly of claim 29 , wherein the housing includes a window to displays one of the plurality of needle numbers.

31. The attachable needle assembly of claim 1 , wherein the follower ring is in contact with the snap ring.

32. The attachable needle assembly of claim 1 , wherein the follower ring moves with the snap ring when the housing moves from the first position to the second position.

33. The attachable needle assembly of claim 1 , wherein rotation of the snap ring causes the follower ring to simultaneously rotate.