Abstract: An adapter for interconnecting in fluid communication a first connection site and a beneficial agent container having a closure. The adapter includes a plate having first and second connection site sides. A wall extends from the plate from the second connection site side and constructed to surround only the closure. This allows containers having varying sized bodies to be received. A cannula structure is rigidly secured in the plate and defines a flow path extending through the plate. The adapter can be provided in an assembly with the beneficial agent contained or in a drug delivery system.