Patent ID: 8092422

Claim:
A two-chamber carpule for use with a pen system comprising a) a cylinder having a proximal end and a distal end, containing an end plug, which is positioned at the proximal end of the cylinder, optionally a stop at the proximal end, an intermediate plug, a bypass, where the distal end is configured to connect to an attachment, the attachment having a proximal end and a distal end, where the attachment comprises, a closure with a distal opening suitable for receiving an application needle and optionally a needle holder, one or more sealing elements for sealing the distal opening of the closure and for sealing the connection between the closure and the cylinder; and b) an axial groove on an inner side of a receiving component of either the distal end of the cylinder or the proximal end of the attachment, where the axial groove is configured to allow pressure to escape when the cylinder and the attachment are joined together during assembly, wherein the cylinder and the attachment when in an assembled state contains a preparation and is configured to be inserted and installed into a pen system.