to separate drugs within a chamber formed beneath a dome - like housing from another biomedically active substance , the chamber is subdivided into two chamber portions by enclosing , within said chamber , a plastic bag or by stretching a membrane thereacross . the plastic bag , or the membrane , respectively , is ruptured upon depression of a terminal element located at the apex of the dome of the housing . the subdivision of the chamber into two chamber portions prevents intermixing of the biologically active substances during storage . one of the chamber portions may retain liquids which are suitable in the article , and preferably are separated from another one of the liquids , such as a surfactant , and thus permits a wide choice , of , respectively , biologically active and other substances . unintended leakage of the substances through a microporous membrane closing off the housing is prevented by applying a cover strip across the membrane .