Beneficial agent delivery system with membrane plug

摘要

A set of membrane plugs, wherein each plug is suitable for use in a delivery system for controlled delivery of a beneficial agent at a predetermined rate, said delivery system comprising:
an implantable capsule having an opening;
a beneficial agent reservoir within the capsule and a beneficial agent delivery outlet through which beneficial agent is released;
a membrane plug that is arranged to be received in the opening of the capsule so as to provide a fluid permeable barrier between an interior and an exterior of the capsule, the membrane plug having a plurality of external ribs for engaging an interior surface of the capsule; and wherein
a) the external ribs are arranged to be located in corresponding grooves in the interior surface of the capsule, the diameter of each rib prior to insertion into the groove being larger than the inner diameter of the corresponding capsule groove by up to 8% of the inner diameter of the groove; and/or
b) a plug clearance exists between an exterior diameter of the membrane plug between the ribs (core diameter) and an interior diameter of the capsule when the plug is inserted into the capsule, wherein the core diameter is between 0.5 and 15 percent smaller than the interior of the capsule;
wherein said rib diameter and/or plug clearance are preselected to achieve the predetermined delivery rate at which the beneficial agent is released from the reservoir,
and wherein each plug in the set has different dimensions such that a desired delivery rate from said delivery system can be achieved by selecting a plug from the set based on the clearance or interference between the plug and an interior surface of the capsule when the plug is installed in the capsule.