Interstitial filtration and collection device and method for long-term monitoring of physiological constituents of the body

An implantable filtration and collection device for collecting a filtrate containing a physiological constituent of the body present in an interstitial body space, said implantable filtration and collection device being operable with a negative pressure generating source to withdraw the filtrate from the interstitial body space, said implantable filtration and collection device comprising:

• a filtration means for filtering a filtrate from interstitial fluid in an interstitial space inside the body, said filtration means including a porous filter made of a material compatible for long-term patency inside the body, said filter adapted to be implanted inside the body in fluid communication with the interstitial space and wherein the pores in said filter are sized not to exceed a predetermined dimension corresponding to the size of the physiological constituent being filtered;
• and
• a filtrate collector connectable to the negative pressure generating source and including an elongate tube connected to said filter in fluid communication therewith and adapted to extend externally of the body with said filter implanted inside the body.