Implantable drug delivery port

A method of forming an implantable drug delivery port comprising a port housing, a fill port washer, a pierceable septum, and a port cover, the method comprising:

• machining the port housing to include an inner sidewall and needle stop defining a fill port cavity for receiving an injectable fluid, wherein the inner sidewall comprises a perimeter edge;
• machining at least one of the perimeter edge of the inner sidewall or a first side of the port washer to form a plurality of filter channels, wherein each filter channel defines a cross-sectional flow area when the first side of the port washer is seated in direct contact with the perimeter edge of the inner sidewall;
• and
• coupling the port cover to the port housing so that the pierceable septum is compressed between at least a second side of the fill port washer and the port cover, wherein the port cover defines an aperture positioned over the pierceable septum and is configured so that a needle can pierce through the septum to deliver the injectable fluid to the fill port cavity.