Patch production

Abstract

A method of producing projections on a patch including providing a mask on a substrate and etching the substrate using an etchant and a passivant to thereby control the etching process and form the projections, wherein the passivant does not include oxygen.

1 . A microprojection array comprising projections on a surface of a substrate, wherein the microprojection array is produced by a method comprising:
 a) providing a mask on the substrate; and,   b) etching the substrate using an etchant and a passivant to thereby control the etching process and form the projections, wherein the passivant does not include oxygen.   
     
     
         2 . A microprojection array according to  claim 1 , wherein the mask includes an organic photo-resist. 
     
     
         3 . A microprojection array according to  claim 1 , wherein the passivant is a gas including:
 a) at least one of:
 i) carbon; and, 
 ii) silicon; and, 
   b) at least one of:
 i) chlorine; and, 
 ii) fluorine. 
   
     
     
         4 . A microprojection array according to  claim 1 , wherein the passivant is at least one of:
 a) a per-fluoride hydrocarbon; and,   b) a fluorinated olefine;   c) Octafluorocyclobutane;   d) Perfluoroisobutene; and,   e) C 4 F 8 .   
     
     
         5 - 6 . (canceled) 
     
     
         7 . A microprojection array according to  claim 1 , wherein the method includes, controlling the etching process by varying etching parameters including at least one of:
 a) a ratio of the etchant to the passivant;   b) a gas flow for at least one of the etchant and the passivant; and,   c) a pressure for at least one of the etchant and the passivant.   
     
     
         8 . A microprojection array according to  claim 7 , wherein the ratio is in the range of 0.25 to 0.60. 
     
     
         9 . A microprojection array according to  claim 7 , wherein the pressure of at least one of the etchant and the passivant is in the range of 0 to 26.7 Pa. 
     
     
         10 . A microprojection array according to  claim 7 , wherein the pressure of at least one of the etchant and the passivant is in the range of 0.67 to 8.0 Pa. 
     
     
         11 . A microprojection array according to  claim 7 , wherein the etchant is supplied at a flow rate in the range of at least one of:
 a) 0 to 200 sccm; and,   b) 40 to 120 sccm.   
     
     
         12 . A microprojection array according to  claim 7 , wherein the passivant is supplied at a flow rate in the range of at least one of:
 a) 0 to 200 sccm; and,   b) 10 to 80 sccm.   
     
     
         13 - 15 . (canceled) 
     
     
         16 . A microprojection array according to  claim 1 , wherein the method of producing the microprojection array further includes, performing post-etch processing. 
     
     
         17 . A microprojection array according to  claim 16 , wherein the post-etch processing includes, chemically sharpening the projections. 
     
     
         18 - 21 . (canceled) 
     
     
         22 . A microprojection array according to  claim 1 , wherein the method of producing the microprojection array further includes, applying a coating to the projections. 
     
     
         23 . A microprojection array according to  claim 22 , wherein the coating is a metallic coating. 
     
     
         24 - 26 . (canceled) 
     
     
         27 . A microprojection array according to  claim 1 , wherein the method of producing the microprojection array further includes coating the projections with a material. 
     
     
         28 . A microprojection array according to  claim 1 , wherein the material is a therapeutic agent. 
     
     
         29 . A microprojection array according to  claim 1 , wherein the patch has a surface area of approximately 0.4 cm 2 . 
     
     
         30 . A microprojection array according to  claim 1 , wherein the projections have a density of between 1,000-30,000 projections/cm 2 . 
     
     
         31 . A microprojection array according to  claim 1 , wherein the projections have a density of 20,000 projections/cm 2    
     
     
         32 . A microprojection array according to  claim 1 , wherein the projections have a length of between 10 to 200 μm. 
     
     
         33 . A microprojection array according to  claim 1 , wherein the projections have a length of 90 μm 
     
     
         34 . A microprojection array according to  claim 1 , wherein the projections have a radius of curvature of greater than 1 μm. 
     
     
         35 . A microprojection array according to  claim 1 , wherein the projections have a radius of curvature greater than 5 μm. 
     
     
         36 . A microprojection array according to  claim 1 , wherein the projections include a support section and a targeting section. 
     
     
         37 . A microprojection array according to  claim 36 , wherein the targeting section has a diameter of less than at least one of:
 a) 1 μm; and,   b) 0.5 μm.   
     
     
         38 . A microprojection array according to  claim 36 , wherein a length for the targeting section is at least:
 a) less than 0.5 μm; and,   b) less than 1.0 μm; and,   c) less than 2.0 μm.   
     
     
         39 . A microprojection array according to  claim 36 , wherein a length for the support section is at least one of:
 a) for epidermal delivery <200 μm;   b) for dermal cell delivery <1000 μm;   c) for delivery to basal cells in the epithelium of the mucosa 600-800 μm; and,   d) for lung delivery of the order of 100 μm in this case.   
     
     
         40 - 42 . (canceled)