| abstract |
A needle assembly has a needle holder that holds a needle and a sheath. The sheath has a needle compartment that accommodates the needle and any spilled drug flowing from the needle. The sheath and the needle holders are detachable. The sheath has an opening communicating with the needle compartment. A liquid barrier, which can comprise a hydrophobic membrane, is positioned in the first opening, blocking the first opening. The liquid barrier allows gas to escape through the first opening but prevent liquid from leaking through the first opening during drug filling stage. In use, the sheath is positioned over the needle of a drug delivery device. The drug delivery device is filled through a separate port until its drug reservoir is completely filled, which is accomplished by filling until the drug spills out through the needle. The sheath maintains the spilled drug within the needle compartment, while air bubbles escape through the liquid barrier. |