Anhydrous drug reservoir for electrolytic transdermal delivery device

Abstract

An electrode assembly and a method of forming an anhydrous reservoir layer of an electrode assembly in an electrotransport transdermal agent delivery device are provided. The reservoir layer is adapted to be placed in agent-transmitting relation with a body surface and an electrode in electrical contact with a power source and the reservoir layer. The method includes the steps of dissolving a beneficial agent in a solvent, applying the solvent and dissolved beneficial agent to a surface of a hydrophilic polymer filtration membrane, removing the solvent from the surface of the filtration membrane, and disposing the beneficial agent/filtration membrane within the electrode assembly.

Wherein, what is claimed is:  
     
         1 . A method of forming an anhydrous reservoir layer of an electrode assembly in an electrically powered electrotransport agent delivery device, the reservoir layer being adapted to be placed in agent-transmitting relation with a body surface and an electrode in electrical contact with a power source and the reservoir layer, the method comprising the steps of: 
 i. dissolving a beneficial agent in a solvent;    ii. applying the solvent and dissolved beneficial agent to a surface of a hydrophilic polymer filtration membrane;    iii. removing the solvent from the filtration membrane;    iv. disposing the beneficial agent/filtration membrane within the electrode assembly.    
     
     
         2 . The method of  claim 1  wherein the solvent comprises water and said dissolving step includes dissolving the beneficial agent in water.  
     
     
         3 . The method of  claim 1  wherein the solvent comprises ethanol and said dissolving step includes dissolving the beneficial agent in ethanol.  
     
     
         4 . The method of  claim 1  wherein the solvent comprises isopropanol and said dissolving step includes dissolving the beneficial agent in isopropanol.  
     
     
         5 . The method of  claim 1  wherein said applying step includes applying the solvent and dissolved beneficial agent to the surface of a polyether sulfone filtration membrane.  
     
     
         6 . The method of  claim 1  wherein said applying step includes applying the solvent and dissolved beneficial agent to the surface of a polysulfone filtration membrane.  
     
     
         7 . The method of  claim 1  wherein said removing step includes drying the filtration membrane.  
     
     
         8 . The method of  claim 7  wherein said drying step includes placing the filtration membrane in a forced air oven.  
     
     
         9 . The method of  claim 7  wherein said drying step includes placing the filtration membrane in a vacuum drying oven.  
     
     
         10 . The method of  claim 7  wherein said drying step includes placing the filtration membrane in a desiccator.  
     
     
         11 . The method of  claim 1  wherein said removing step includes lyophilizing the filtration membrane.  
     
     
         12 . A multilaminate dry state electrode assembly for an electrically powered electrotransport agent delivery device, the electrode assembly having a reservoir layer including a substantially non-hydrated hydratable matrix for containing an agent to be delivered, the reservoir layer being adapted to be placed in agenttransmitting relation with a body surface and an electrode layer in electrical contact with both the reservoir layer and a power source, the reservoir layer formed by the process of: 
 v. dissolving the agent in a solvent;    vi. applying the solvent and dissolved agent to a surface of a hydrophilic polymer filtration membrane;    vii. removing the solvent from the surface of the hydrophilic polymer filtration membrane;    viii. disposing the agent/polymer filtration membrane within the electrode assembly.    
     
     
         13 . The electrode assembly of  claim 12  wherein the solvent comprises water.  
     
     
         14 . The electrode assembly of  claim 12  wherein the solvent comprises ethanol.  
     
     
         15 . The electrode assembly of  claim 12  wherein the solvent comprises isopropanol.  
     
     
         16 . The electrode assembly of  claim 12  wherein said hydrophilic polymer filtration membrane comprises a polyether sulfone filtration membrane.  
     
     
         17 . The electrode assembly of  claim 12  wherein said hydrophilic polymer membrane comprises a polysulfone filtration membrane.  
     
     
         18 . A multilaminate dry state electrode assembly for an electrotransport agent delivery device, said electrode assembly comprising: 
 ix. a reservoir layer including a substantially non-hydrated hydratable matrix adapted to contain an agent to be delivered, the reservoir layer being adapted to be placed in agent-transmitting relation with a body surface, and    x. an electrode layer in electrical contact with both the reservoir layer and a power source,    xi. wherein said hydratable matrix comprises a hydrophilic polymer filtration membrane.    
     
     
         19 . The electrode assembly of  claim 18  wherein said filtration membrane is microporous.  
     
     
         20 . The electrode assembly of  claim 19  wherein said filtration membrane has a pore size between 0.5 and 10.0 μ.  
     
     
         21 . The electrode assembly of  claim 20  wherein said filtration membrane has a pore size between 0.5 and 1.5 μ.  
     
     
         22 . The electrode assembly of  claim 18  wherein the filtration membrane is selected from the group consisting of acrylic copolymers, glass fiber, nylon, mixed cellulose esters, polyvinylidene fluoride, and polypropylene.  
     
     
         23 . The electrode assembly of  claim 18  wherein said filtration membrane comprises a polyether sulfone filtration membrane.  
     
     
         24 . The electrode assembly of  claim 18  wherein said filtration membrane comprises a polysulfone filtration membrane.  
     
     
         25 . The electrode assembly of  claim 18  further comprising a hydrogel layer between the electrode layer and the matrix.  
     
     
         26 . The electrode assembly of  claim 18  further comprising a hydrogel layer on the skin proximal side of the matrix.  
     
     
         27 . The electrode assembly of  claim 18  wherein the filtration membrane comprises a thickness of about 2-10 mils.  
     
     
         28 . The electrode assembly of  claim 27  wherein the thickness is about 3-6 mils.  
     
     
         29 . The electrode assembly of  claim 18  wherein the matrix is imbibed with drug before incorporation into the electrotransport device.