Transdermal drug delivery method and system

Abstract

The invention concerns a transdermal delivery system for controlled dispensing of an active substance to and through a porous surface. A certain amount of fluid comprising at least one active substance and at least one solvent is dispensed into an administration reservoir. In the administration reservoir the at least one solvent is separated from the administration reservoir by a solvent recovery means such that the active substance achieves a certain level on an interface device which is permeable for the one active substance. Thereby the active substance is absorbable via diffusion from the interface device by a porous surface to be treated.

1 . A device for transdermal administration of an active substance, the device comprising:
 a reservoir configured to hold a solution, the solution comprising the active substance and a solvent;   a piston positioned within the reservoir and configured to move the solution towards the porous skin interface;   a porous skin interface adapted to receive the solution from the reservoir and to transfer the active substance to skin; and   a solvent removal element configured to receive evaporated solvent from the porous skin interface.   
     
     
         2 . The device of  claim 1 , further comprising a vapor permeable material positioned between the porous skin interface and the reservoir. 
     
     
         3 . The device of  claim 1 , further comprising a valve configured to control the flow of solution from the reservoir to the skin interface. 
     
     
         4 . The device of  claim 3 , further comprising a programmable control unit configured to control the valve. 
     
     
         5 . The device of  claim 1 , wherein the porous skin interface comprises adhesive. 
     
     
         6 . The device of  claim 1 , further comprising an administration reservoir adapted to receive the solution from the reservoir and to communicate with the porous skin interface. 
     
     
         7 . The device of  claim 1 , further comprising a housing into which the reservoir, porous skin interface, and solvent removal element are incorporated. 
     
     
         8 . A method for transdermally administering an active substance to a subject, the method comprising:
 placing a porous skin interface of a transdermal dispensing system into contact with the subject's skin;   dispensing a solution of the active substance and a solvent from a reservoir of the dispensing system to the porous skin interface; and   moving solvent from the porous skin interface into a solvent removal element of the dispensing system.   
     
     
         9 . The method of  claim 8 , wherein the dispensing step comprises moving a piston within the reservoir. 
     
     
         10 . The method of  claim 8 , wherein the moving step comprises moving solvent through a vapor permeable material into the solvent removal element. 
     
     
         11 . The method of  claim 10 , wherein the dispensing step comprises actuating a valve to control flow of solution from the reservoir to the skin interface. 
     
     
         12 . The method of  claim 11 , wherein the actuating step comprises actuating the valve automatically according to a preset administration regime. 
     
     
         13 . The method of  claim 8 , wherein the dispensing step comprises flowing the solution from the reservoir into an administration reservoir before reaching the porous skin interface. 
     
     
         14 . The method of  claim 8 , further comprising adhesively attaching the dispensing system to the subject.