I never understood what you all were talking about when you talked about breaking the glass vial open to use the B12. I recently ordered B12 vials from Canada for my daughter. When she used the first one yesterday, she told me that these vials were different than the ones I get from my pharmacy. She said these have glass tops that need to be broken open. She dropped the first vial when trying to open it and it was ruined because it broke into pieces on the floor. The vials I get from here in the US have a little plastic lid on the vial which you pry off. Under the lid the mouth of the bottle is covered in a rubber like material which you don't remove, you just insert the needle into the bottle and draw out the B12 liquid.
Now all of the talk about opening vials makes sense. I wonder why there are different types of seals. Is one better than the other when it comes to preserving the integrity of the B12.