Microfabricated nanopore device for sustained release of therapeutic agent

Abstract

A drug delivery device that includes a capsule for implantation into the body; the capsule further includes a reservoir for containing a substance such as a therapeutic agent, at least one port for allowing the substance to diffuse from or otherwise exit the reservoir, and a nanopore membrane in communication with the capsule at or near the exit port for controlling the rate of diffusion of the substance from the exit port. The device also includes an optional screen for providing structural stability to the nanopore membrane and for keeping the pores of the nanopore membrane clear. One embodiment of the drug delivery device includes an osmotic engine internal to the device for creating fluid flow through the device.

What is claimed: 
     
         1 . A drug delivery device, comprising:
 a capsule for implantation into the body, said capsule comprising a reservoir, an exit port in communication with the reservoir and a nanopore membrane in communication with the exit port, wherein said reservoir comprises a therapeutic substance having a Stoke's diameter in an amount for release of the therapeutic substance for several weeks at a rate that approaches zero-order release as the therapeutic substance diffuses through pores in the nanopore membrane that have a diameter 1-5 times the Stoke's diameter of the therapeutic substance.   
     
     
         2 . The drug delivery device of  claim 1 , wherein said capsule further comprises a first end and a second end, and wall extending from the first end to the second end. 
     
     
         3 . The drug delivery device of  claim 2 , wherein said capsule is tapered at the first and second ends. 
     
     
         4 . The drug delivery device of  claim 1 , wherein said capsule is substantially cylindrical in cross section. 
     
     
         5 . The drug delivery device of  claim 1 , wherein said nanopore membrane comprises an array of parallel, annular channels. 
     
     
         6 . The drug delivery device of  claim 5 , wherein channels in the array of parallel, annular channels have a pore size of between 2-100 nm. 
     
     
         7 . The drug delivery device of claim  14 , wherein said nanopore membrane comprises an array of parallel, rectangular channels. 
     
     
         8 . A device, comprising:
 a cylindrical capsule having a first end and a second end and a fluid impermeable wall extending from the first end to the second end, the wall defining a reservoir for containing a therapeutic agent, the device further comprising a membrane with an array of parallel pores with dimensions that physically constrain motion of the therapeutic agent in each pore of the array to control release of the therapeutic agent from the device; and wherein said device is manufactured from titanium and sized for implantation into an anatomical compartment of the body.   
     
     
         9 . A method for delivering a therapeutic agent, comprising
 providing a cylindrical capsule having a first end and a second end and a fluid impermeable wall extending from the first end to the second end, the wall defining a reservoir for containing a therapeutic agent, the device further comprising a membrane having pores with dimensions that physically constrain motion of the therapeutic agent in each pore of the array to control release of the therapeutic agent from the device; and wherein said device is manufactured from titanium and sized for implantation into an anatomical compartment of the body, said device being indicated for implantation.   
     
     
         10 . A method for delivering a peptide or a protein, comprising
 providing a device comprising a capsule for implantation into the body, said capsule comprising a first end, a second end and a fluid impermeable wall extending from the first end to the second end to define a reservoir; said capsule further comprising an exit port in communication with the reservoir and a nanopore membrane in communication with the exit port, wherein said device comprises a peptide or a protein in the reservoir, said peptide or protein having a Stoke's diameter, and wherein said nanopore membrane has pores between about 1-5 times the Stoke's diameter of the peptide or protein, and wherein an amount of the peptide or protein is contained in the reservoir for release at a rate that approaches zero-order release for a period of several weeks.