can be formed and attached to the osmotic pump also the orifice module can be coupled to a membrane module which can then be attached to the osmotic pump the imbibition rate reducer can be installed on the osmotic pump post manufacture and pre implantation to reduce the imbibition rate of the osmotic pump by a selected amount where a reduction in imbibition rate produces a corresponding reduction in the delivery rate of the osmotic pump for illustration purposes fig4 a shows an osmotic pump system 400 having an imbibition rate reducer e g the orifice module 200 installed on an osmotic pump 402 according to an embodiment of the invention the internal structure of the osmotic pump 402 is presented for illustration purposes only and is not to be construed as limiting the present invention the present invention is generally applicable to all osmotic pumps having any number of shapes and to all such pumps administered in implantable osmotic delivery techniques the osmotic pump 402 as illustrated in fig4 a includes an elongated cylindrical capsule 404 the capsule 404 may be sized such that it can be implanted within a body in fig4 a one end 406 of the capsule 404 is closed and the other end 408 of the capsule 404 is open the closed end 406 includes a delivery port 410 in an alternative embodiment the closed end 406 may be modified to include a flow modulator not shown such as taught by peterson et al in u s pat no 6 524 305 a semipermeable membrane plug 412 is received in the open end 408 of the capsule 404 the.