PECVD coating methods for capped syringes, cartridges and other articles
A method is disclosed in which a vapor-deposited coating or layer is directly or indirectly applied to at least a portion of the internal wall of the barrel of a capped pre-assembly comprising a barrel, optionally a dispensing portion, and a cap. The cap is secured to the barrel and at least substantially isolates the distal opening of the dispensing portion from pressure conditions outside the cap. A vapor-deposited coating or layer is applied directly or indirectly to at least a portion of the internal wall of the barrel while the pre-assembly is capped. The coating or layer is applied under conditions effective to maintain communication from the barrel lumen to the exterior via the front opening, optionally further via the dispensing portion lumen if present, at the end of the applying step. The capped pre-assembly can be pressure tested easily and rapidly, for example with a test duration between 1 and 60 seconds, to determine whether it has container closure integrity.
1. A method comprising:
providing a capped pre-assembly comprising:
a barrel comprising an internal wall defining a barrel lumen and a front opening through the internal wall;
a dispensing portion comprising a hypodermic needle secured to the barrel, the hypodermic needle comprising a distal opening located outside the barrel and a dispensing portion lumen communicating between the front opening of the barrel and the distal opening of the dispensing portion; and
a cap secured to the barrel and at least substantially isolating the front opening from pressure conditions outside the cap, the cap being sufficiently permeable to a sterilizing gas to sterilize the portions of the assembly isolated by the cap; and
applying a plasma enhanced chemical vapor deposition (PECVD) coating or layer directly or indirectly to at least a portion of the internal wall of the barrel, while the pre-assembly is capped and the dispensing portion lumen of the hypodermic needle is communicating between the front opening and the distal opening of the dispensing portion, under conditions effective to maintain communication between the barrel lumen and the exterior via the front opening at the end of the applying step, in which essentially no PECVD coating is formed in the dispensing portion lumen of the hypodermic needle.
2. The method of claim 1 , further comprising, before the providing step, assembling the capped pre-assembly.
3. The method of claim 2 , further comprising, before the assembling step, forming the barrel.
4. The method of claim 3 , in which the barrel is formed by placing the dispensing portion in an injection mold and injection molding thermoplastic material about the dispensing portion, thus forming the barrel and securing the dispensing portion to the barrel.
5. The method of claim 1 , in which the cap is made of a thermoplastic elastomer.
6. The method of claim 1 , in which the cap of the pre-assembly isolates the distal opening at least partially due to: contact between the cap and the distal opening, contact between the cap and the barrel, or both.
7. The method of claim 1 , in which the barrel further comprises an opening spaced from the dispensing portion and communicating through the internal wall.
8. The method of claim 7 , in which the vapor-deposited coating or layer is applied through the opening.
9. The method of claim 8 , in which the PECVD coating or layer is applied by flowing a reactant vapor material through the opening and employing plasma enhanced chemical vapor deposition to deposit a reaction product of the reactant vapor material on the internal wall of the barrel.
10. The method of claim 1 , further comprising, while drawing at least a partial vacuum through the barrel opening, measuring the pressure decay of gas drawn from the barrel opening and any leakage paths.
11. The method of claim 10 , further comprising comparing the pressure decay of gas to a predetermined standard to determine the container closure integrity of the capped pre-assembly.
12. The method of claim 11 , in which the pressure decay is measured with sufficient precision to detect a pressure decay due to an intact container versus a container having a single perforation in the cap having a diameter of 5 microns, to 0.5 microns.
13. The method of claim 12 , in which the pressure decay is measured within a time between 1 second and 60 seconds.
14. The method of claim 10 , in which the pressure decay of gas drawn from the barrel opening and any leakage paths is measured after applying a vapor-deposited coating or layer.
15. The method of claim 1 , in which the vapor-deposited coating or layer is a barrier coating or layer.