Adaptor for a drug delivery device and drug delivery device

An adaptor for a drug delivery device having a reservoir and a longitudinal tip having an outer surface and a longitudinal channel for dispensing any material stored into the reservoir, the adaptor comprising:

• a distal part defining a connecting ring;
• a proximal part defining a mounting ring having an inner surface;
• and
• an annular ring between the connecting ring and the mounting ring,
• wherein with the adaptor mounted around the longitudinal tip of the drug delivery device, at least one annular space is created between an inner annular recess of said inner surface of the mounting ring and said outer surface of the longitudinal tip, said at least one annular space accommodates an adhesive layer to bond said adaptor to said longitudinal tip,
• wherein the annular ring is provided at a distal extremity of the inner surface of the mounting ring,
• wherein a proximal end of the inner annular recess is open and a distal end of the inner annular recess is closed by a proximal wall of the annular ring, and
• wherein the inner surface of the mounting ring comprises at least one protrusion wherein, with the adaptor mounted around the longitudinal tip of the drug delivery device, said at least one protrusion protrudes into said at least one annular space.