16 and is substantially impermeable to the passage of a beneficial agent and other ingredients contained in delivery device 10 in another embodiment wall 12 comprises at least in part a semipermeable composition with the remainder of the wall comprising a different composition substantially impermeable to the passage of fluid as well as of the ingredients in the device materials useful as wall forming compositions are well known in the art examples of which are described in the patents previously cited herein the disclosures of which are incorporated herein by reference wall 12 is non toxic and it maintains its physical and chemical integrity that is it does not erode during the dispensing period device 10 in a presently preferred embodiment is manufactured with wall 12 as a single unit member by injection molding or the like compartment 16 contains a beneficial agent formulation 17 which comprises a beneficial agent together with a carrier for the beneficial agent the carrier material may be a fluid a solid a semi solid or in a presently preferred embodiment a thermo responsive composition materials suitable as carriers for the beneficial agent are known in the art and are described in the patents previously cited herein compartment 16 further contains displacement means or expandable driving member 20 that is in layered contact with a contacting surface 21 of beneficial agent formulation 17 the expandable driving member usually comprises a fluid.