An implantable access device suitable for delivering a liquid medication to a site remote from the site of port implantation is disclosed, which contains a filter assembly for removing particulate material from fluid injected into the port. The filter assembly of the invention contains a first reservoir chamber having cutouts, recesses, and/or sharp corners in which particulate material may be trapped, and additionally having a first wall forming a filter barrier capable of 360.degree. of fluid flow therethrough. The implantable access device may also include an infusion pump apparatus coupled to the access device. A filter assembly for insertion into an implantable treatment material device is also described.