Pen needle assembly for delivering drug solutions

Abstract

In one aspect, a pen needle assembly is provided herein which includes a hub, and a needle fixed to the hub, the needle having proximal and distal ends with a lumen extending therebetween. The needle extends distally from the hub to define an exposed length between the distal end of the needle and the hub in the range of about 5.0 to 9.0 mm. The hub defines a post formed about the needle, the post having a distally-facing first skin engaging surface. The exposed length of the needle extends distally from the first skin engaging surface. The hub also defines a distally-facing second skin engaging surface which at least partially circumscribes the first skin engaging surface. The second skin engaging surface being located proximally of the first skin engaging surface. Advantageously, a pen needle assembly is provided having two skin engaging surfaces which provide stability in achieving subcutaneous injections.

What is claimed is: 
     
         1 . A pen needle assembly comprising:
 a hub having a proximal end and a distal end with an axial face;   a collar extending axially from said axial face of said hub and spaced radially inward from a peripheral edge of said body, said collar having an axially facing end wall;   a post extending from said end wall, said post having a distal end and a central opening extending through said post and receiving a needle fixed to said post, said needle extending axially from said post, said distal end of said post having an annular axial face spaced radially outward from said needle and defining a first annular skin contact surface;   a member having an annular shape and extending axially from said distal end of said collar, said member spaced radially outward from said post and having an annular axial face spaced axially from said axial face of said post, and where said axial face of said post is spaced distally from said axial face of said member a distance of at least about 0.07.   
     
     
         2 . The pen needle assembly according to  claim 1 , wherein said needle extends distally from said hub to define an exposed length in the range of about 5.0 to 9.0 mm, and where said axial face of said post is spaced distally from said axial face of said member a distance of about 0.07 to about 0.10 inch. 
     
     
         3 . The pen needle assembly according to  claim 1 , wherein
 said annular axial face of said post has a first diameter D 1  and said annular axial surface of said annular member has a second diameter D 2 , and where a ratio of said diameter D 1  to said diameter D 2  is about 0.25:1 to about 0.58:1.   
     
     
         4 . The pen needle assembly according to  claim 3 , wherein
 said ratio of said first diameter D 1  to said second diameter D 2  is about 0.36:1.   
     
     
         5 . The pen needle assembly according to  claim 1 , wherein
 said annular axial face of said post is spaced from said annular axial face of said annular member a distance of about 0.07 to 0.10 inch.   
     
     
         6 . The pen needle assembly according to  claim 5 , wherein
 said axial face of said post is radially spaced from said annular face of said member a distance of about 0.09 inch.   
     
     
         7 . The pen needle assembly according to  claim 1 , wherein
 said annular member is radially spaced from said post a distance to form an annular recess between said post and said annular member.   
     
     
         8 . The pen needle assembly according to  claim 1 , further comprising
 a shell configured for releasable retainment on said hub, said shell being retainable on said hub with said shell covering at least a portion of said needle, the force of said retainment being sufficiently great to maintain said shell retained on said hub with said pen needle assembly being mounted to a medical pen injector with the medical pen injector being shaken to prepare a medicament contained therein for administration to a patient.   
     
     
         9 . The pen needle assembly according to  claim 8 , wherein said releasable retainment is obtained by one or more of the group consisting of frictional interengagement, frangible connection, mechanical connection, fusion and adhesion. 
     
     
         10 . A pen needle assembly comprising:
 a hub having a proximal end and a distal end with an axial face;   a post extending axially from said distal end of said hub, said post having a distal end and a central opening extending through said post and receiving a needle, where said needle is fixed to said post and extends axially from said post, said distal end of said post having an annular axial face spaced radially outward from said needle and defining a first annular skin contact surface; and   a member extending axially from said distal end of said body, said member having an outer peripheral edge spaced radially outward from said post and having an axially facing distal surface spaced axially from said annular axial face of said post, and where said annular axial face of said post is spaced axially from said distal surface of said annular member a distance of about 0.07 to about 0.10 inch.   
     
     
         11 . The pen needle assembly according to  claim 10 , wherein said hub further comprises
 a body having a collar extending axially from said distal end of said body and spaced radially inward from a peripheral edge of said body, said collar having an end wall, and where said post and said member extend from said end wall.   
     
     
         12 . The pen needle assembly according to  claim 11 , wherein said member comprises a plurality of fins extending radially outward from said post, said fins having an axially facing surface spaced proximally from said distal end of said post. 
     
     
         13 . The pen needle assembly according to  claim 12 , wherein each of said fins has a radial end face oriented substantially parallel to a longitudinal axis of said hub. 
     
     
         14 . The pen needle assembly according to  claim 11 , wherein said distal end of said post has a substantially conical shaped portion. 
     
     
         15 . The pen needle assembly according to  claim 11 , wherein said member has an annular axial face spaced axially from said annular axial face of said post. 
     
     
         16 . The pen needle assembly according to  claim 11 , wherein said needle extends distally from said hub to define an exposed length in the range of about 5.0 to 9.0 mm. 
     
     
         17 . The pen needle assembly according to  claim 15 , wherein said annular axial face of said post has a first diameter D 1  and said annular axial face of said member has a second diameter D 2 , and where a ratio of said diameter D 1  to said diameter D 2  is about 0.25:1 to about 0.58:1. 
     
     
         18 . The pen needle assembly according to  claim 16 , said ratio of said first diameter D to said second diameter D 2  is about 0.36:1. 
     
     
         19 . The pen needle assembly according to  claim 15 , wherein said annular axial face of said post is spaced from said annular axial face of said annular member a distance of about 0.07 to 0.10 inch. 
     
     
         20 . The pen needle assembly according to  claim 19 , wherein said axial face of said post is radially spaced from said annular surface of said annular member a distance of about 0.09 inch. 
     
     
         21 . The pen needle assembly according to  claim 19 , wherein said axial face of said post is radially spaced from said annular surface of said annular member a distance of about 0.09 inch. 
     
     
         22 . A method of injecting a medicament to a patient, comprising the steps of:
 connecting a pen needle assembly to a medical pen injector containing the medicament,   said pen needle assembly comprising;   a hub having a proximal end and a distal end with an axial face;   a collar extending from said axially from said axial face of said hub and spaced radially inward from a peripheral edge of said body, said collar having an axially facing end wall;   a post extending from said end wall, said post having a distal end and a central opening extending through said post and receiving a needle fixed to said post and extending axially from said post, said distal end of said post having an annular axial face spaced radially outward from said needle and defining a first annular skin contact surface;   an annular member extending axially from said distal end of said collar, said annular shaped member spaced radially outward from said post and having an annular axial face spaced axially from said axial face of said post, and where said axial face of said post is spaced distally from said axial face of said annular member a distance of about 0.07 to about 0.10 inch;   introducing said needle into the patient where said annular axial face of said post and said annular axial face of said annular member contact a surface of the skin of the patient to limit a depth of penetration; and   injecting the medication into the patient.   
     
     
         23 . The method according to  claim 22 , wherein said needle extends distally from said hub to define an exposed length in the range of about 5.0 to 9.0 mm. 
     
     
         24 . The method according to  claim 23 , wherein said annular axial face of said post has a first diameter D 1  and said annular axial surface of said annular member has a second diameter D 2 , and where a ratio of said diameter D 1  to said diameter D 2  is about 0.25:1 to about 0.58:1. 
     
     
         25 . The method according to  claim 24 , wherein said annular axial face of said post is spaced from said annular axial face of said annular member a distance of about 0.07 to 0.10 inch. 
     
     
         26 . The method according to  claim 25 , said annular member is radially spaced from said post a distance to form an annular recess between said post and said annular member.