Abstract: A storage receptacle sealing and transfer apparatus is disclosed for selectively enabling sealing and transfer of material to and from the receptacle. The apparatus is particularly useful for maintaining and later transferring drug and associated materials, under sterile conditions, to achieve mixing, as, is necessary, for example, in reconstituting a drug by mixing the drug with a diluent prior to delivery to a patient. The transfer apparatus is mounted at the aperture, or mouth, of a storage receptacle to seal the aperture until the contents are needed, and then to permit sterile transfer from one receptacle to another receptacle through a central passage.