Implantable drug storage devices for drug delivery

Abstract

In one embodiment, a fluid storage device includes a rigid outer housing that defines a septum cavity, a reservoir cavity, and a channel that extends between the two cavities, the outer housing further defining an outlet in fluid communication with the reservoir cavity, a septum provided within the septum cavity, the septum being made of an elastic polymer and facilitating refilling of the fluid storage device, and a thin, collapsible membrane that does not generate significant restoring forces when it is deformed as fluid is drawn from the reservoir cavity and, therefore, does not completely or partially return to its initial non-deformed shape even if the outlet of the device remains open after doses are administered.

1 . A fluid storage device comprising:
 an outer housing that defines a septum cavity, a reservoir cavity, and a channel that extends between the septum cavity and the reservoir cavity, the outer housing further defining an outlet in fluid communication with the reservoir cavity; and   a septum provided within the septum cavity, the septum being made of an elastic polymer and facilitating refilling of the fluid storage device, the septum being compressed around its peripheral edges such that a center of the septum bows outward.   
     
     
         2 . The fluid storage device of  claim 1 , wherein the outer housing comprises a base member and a septum cavity cap that covers the septum cavity. 
     
     
         3 . The fluid storage device of  claim 2 , wherein the septum cavity cap includes a refill port that provides access to the septum. 
     
     
         4 . The fluid storage device of  claim 2 , wherein the septum cavity cap is configured to compress the peripheral edges of the septum against an internal ledge of the base member to create radially inward compressive forces within the septum that enable the septum to close needle punctures to prevent leaking. 
     
     
         5 . The fluid storage device of  claim 4 , wherein the septum cavity cap includes an annular compression ring on its bottom that compresses the septum. 
     
     
         6 . The fluid storage device of  claim 2 , wherein each of the base member and the septum cavity cap are coated with a biocompatible polymer. 
     
     
         7 . The fluid storage device of  claim 2 , wherein the septum cavity cap includes a raised peripheral ridge on its top that facilitates location of the fluid storage device after it is implanted under the skin of a subject. 
     
     
         8 . The fluid storage device of  claim 2 , wherein the base member defines a bottom of the septum cavity, a bottom of the reservoir cavity, and the channel that extends between the septum cavity and the reservoir cavity. 
     
     
         9 . The fluid storage device of  claim 1 , wherein the septum is approximately 0.5 to 3 µm thick. 
     
     
         10 . The fluid storage device of  claim 1 , wherein the septum is made out of biocompatible silicone and is coated with a biocompatible polymer. 
     
     
         11 . The fluid storage device of  claim 10 , wherein the biocompatible polymer is parylene. 
     
     
         12 . The fluid storage device of  claim 1 , wherein the device has a height dimension no greater than 3 mm. 
     
     
         13 . The fluid storage device of  claim 1 , wherein the device is a normally open device that comprises no valves or other actuatable devices that are configured to impede a flow of fluid to and from the reservoir cavity. 
     
     
         14 . The fluid storage device of  claim 1 , further comprising a reservoir membrane that is deformed as fluid is drawn from the reservoir cavity and does not to completely or partially return to its initial non-deformed shape even if the outlet of the device remains open after doses are administered. 
     
     
         15 . The fluid storage device of  claim 14 , further comprising a reservoir cavity cap that covers the reservoir cavity, wherein the reservoir cavity cap includes one or more vent openings through which fluids can pass in and out of the reservoir cavity above the reservoir membrane. 
     
     
         16 . An implantable drug delivery system comprising: a fluid storage device including:
 a rigid outer housing that defines a septum cavity, a reservoir cavity, and a channel that extends between the septum cavity and the reservoir cavity, the outer housing further defining an outlet in fluid communication with the reservoir cavity,   a septum provided within the septum cavity, the septum being made of an elastic polymer and facilitating refilling of the fluid storage device, the septum being compressed around its peripheral edges such that a center of the septum bows outward, and   a micropump in fluid communication with the outlet of the fluid storage device configured to draw fluid from the device and administer it to a subject in which the drug delivery system is implanted.   
     
     
         17 . The drug delivery system of  claim 16 , wherein the outer housing comprises a base member and a septum cavity cap that covers the septum cavity. 
     
     
         18 . The drug delivery system of  claim 17 , wherein the septum cavity cap is configured to compress the peripheral edges of the septum against an internal ledge of the base member to create radially inward compressive forces within the septum that enable the septum to close needle punctures to prevent leaking. 
     
     
         19 . The drug delivery system of  claim 18 , wherein the septum cavity cap includes an annular compression ring on its bottom that compresses the septum. 
     
     
         20 . The drug delivery system of  claim 16 , further comprising a reservoir membrane that is deformed as fluid is drawn from the reservoir cavity and does not to completely or partially return to its initial non-deformed shape even if the outlet of the device remains open after doses are administered.