Multi-dose vial (revision 1)

A multi-dose vial, termed a multiple-dose container in compendial language, is a container of an injectable preparation intended to permit withdrawal of successive portions of its contents without change in the strength, quality or purity of the remainder. The definition is functional: it describes an intention and the conditions that make the intention safe, not a size or a shape. A 10 mL vial may be a single-dose or a multiple-dose container depending on its formulation and its labelling.^[1]

Two requirements follow from repeated entry. Because each penetration of the closure is an opportunity for microbial ingress, and because the contents are held at or near room temperature for a period afterwards, a multiple-dose preparation must contain an antimicrobial preservative whose effectiveness has been demonstrated by the challenge testing described in USP <51>. And because the preservative controls but does not eliminate risk, the period during which the container may be used after its first puncture is limited, conventionally to 28 days unless the manufacturer specifies otherwise.^[2][3]