Method and apparatus for coating skin piercing microprojections

Abstract

An Apparatus and method are provided for selectively applying an agent-containing liquid coating to extremely tiny skin piercing microprojections ( 10 ). The coating solution is applied to the skin piercing microprojections ( 10 ) using a coating technique which selectively coats only the skin piercing microprojections ( 10 ) and not to substrate ( 12 ) from which the microprojections ( 10 ) extend, and the dried. The coating method includes providing an agent-containing coating liquid and conveying the liquid to a liquid holding surface having a coating transfer region. The depth of the coating liquid at the coating transfer region is precisely controlled. The microprojections are then immersed to a predetermined level in the coating liquid. The liquid that coats the microprojections ( 10 ) is then dried to form a solid agent-containing coating on the microprojections ( 10 ).

1 - 13 . (canceled) 
   
   
       14 . An apparatus for coating applying an agent-containing coating liquid onto a plurality of microprojections extending from a surface or edge of a substrate substantially without coating the substrate, comprising:
 a rotatable member with a liquid holding surface, said liquid holding surface having a coating transfer region;   a coating liquid conveyor for providing said coating liquid at said coating transfer region;   a coating liquid depth controller for controlling the depth of said coating liquid at said coating transfer region to a predetermined depth; and   a substrate conveyor for conveying said microprojections at a predetermined level of immersion through said coating liquid at said coating transfer region.   
   
   
       15 . An apparatus for applying an agent-containing coating liquid onto a plurality of microprojections extending from a surface or edge of a substrate substantially without coating said substrate, comprising:
 a rotatable member with a curved liquid holding surface, said curved liquid holding surface having a coating transfer region;   a coating liquid conveyor for providing said coating liquid at said coating transfer region;   a coating liquid depth controller for controlling the depth of said coating liquid at said coating transfer region to a predetermined depth; and   a substrate conveyor for conveying said microprojections at a predetermined level of immersion through said coating liquid at said coating transfer region.   
   
   
       16 . An apparatus for applying an agent-containing coating liquid onto a plurality of microprojections extending from a surface or edge of a substrate substantially without coating said substrate, comprising:
 a liquid holding surface having a coating transfer region, said liquid holding surface being an outer surface of a rotatable cylindrically-shaped roller;   a coating liquid conveyor for providing said coating liquid at said coating transfer region;   a coating liquid depth controller for controlling the depth of said coating liquid at said coating transfer region to a predetermined depth; and   a substrate conveyor for conveying said microprojections at a predetermined level of immersion through said coating liquid at said coating transfer region.   
   
   
       17 . An apparatus for applying an agent-containing coating liquid onto a plurality of microprojections extending from a surface or edge of a substrate substantially without coating said substrate, comprising:
 a liquid holding surface having a coating transfer region, said liquid holding surface being an outer surface of a rotatable cylindrically-shaped roller;   a coating liquid conveyor for providing said coating liquid at said coating transfer region;   a coating liquid depth controller for controlling the depth of said coating liquid at said coating transfer region to a predetermined depth; and   a substrate conveyor for conveying said microprojections at a predetermined level of immersion through said coating liquid at said coating transfer region, wherein said coating liquid conveyor comprises rotating said roller through a bath of said coating liquid.   
   
   
       18 . An apparatus for applying an agent-containing coating liquid onto a plurality of microprojections extending from a surface or edge of a substrate substantially without coating said substrate, comprising:
 a liquid holding surface having a coating transfer region, said liquid holding surface being an outer surface of a rotatable cylindrically-shaped roller;   a coating liquid conveyor for providing said coating liquid at said coating transfer region;   a coating liquid depth controller comprising a doctor blade for controlling the depth of said coating liquid at said coating transfer region to a predetermined depth; and   a substrate conveyor for conveying said microprojections at a predetermined level of immersion through said coating liquid at said coating transfer region, wherein said coating liquid conveyor comprises rotating said roller through a bath of said coating liquid.   
   
   
       19 . An apparatus for applying an agent-containing coating liquid onto a plurality of microprojections extending from a surface or edge of a substrate substantially without coating said substrate, comprising:
 a liquid holding surface having a coating transfer region, said liquid holding surface being an outer surface of a rotatable cylindrically-shaped roller;   a coating liquid conveyor for providing said coating liquid at said coating transfer region;   a coating liquid depth controller for controlling the depth of said coating liquid at said coating transfer region to a predetermined depth; and   a substrate conveyor for conveying said microprojections at a predetermined level of immersion through said coating liquid at said coating transfer region, wherein herein said coating liquid conveyor comprises rotating said roller through a bath of said coating liquid, wherein said coating liquid depth controller comprises a second roller, substantially parallel with said liquid holding surface and spaced a predetermined distance therefrom and forming a nip therebetween.   
   
   
       20 . An apparatus for coating applying an agent-containing coating liquid onto a plurality of microprojections extending from a surface or edge of a substrate substantially without coating said substrate, comprising:
 a liquid holding surface having a coating transfer region, said liquid holding surface being an outer surface of a rotatable cylindrically-shaped roller;   a coating liquid conveyor for providing said coating liquid at said coating transfer region;   a coating liquid depth controller for controlling the depth of said coating liquid at said coating transfer region to a predetermined depth; and   a substrate conveyor for conveying said microprojections at a predetermined level of immersion through said coating liquid at said coating transfer region, wherein said coating liquid conveyor comprises rotating said roller through a bath of said coating liquid, wherein said coating liquid depth controller comprises a second roller, substantially parallel with said liquid holding surface roller and spaced a predetermined distance therefrom and forming a nip therebetween, and wherein said two rollers rotate in the same rotational direction.   
   
   
       21 . (canceled) 
   
   
       22 . An apparatus for coating an agent-containing liquid onto a plurality of microprojections extending from a surface or edge of a substrate substantially without coating the substrate, comprising:
 an immobile liquid holding surface having a coating transfer region;   a coating liquid conveyor for providing the coating liquid at the coating transfer region;   a coating liquid depth controller for controlling the depth of the coating at the coating transfer region to a predetermined depth; and   a substrate conveyor for conveying the microprojections at a predetermined level of immersion through the coating liquid at the coating transfer region.   
   
   
       23 . An apparatus for coating an agent-containing liquid onto a plurality of microprojections extending from a surface or edge of a substrate substantially without coating the substrate, comprising:
 an immobile liquid holding surface having a coating transfer region;   a coating liquid conveyor for providing the coating liquid at the coating transfer region;   a coating liquid depth controller for controlling the depth of the coating at the coating transfer region to a predetermined depth; and   a substrate conveyor for conveying the microprojections at a predetermined level of immersion through the coating liquid at the coating transfer region, wherein the coating liquid conveyor causes the coating liquid to flow, by force of gravity, over the immobile liquid holding surface.   
   
   
       24 . An apparatus for coating an agent-containing liquid onto a plurality of microprojections extending from a surface or edge of a substrate substantially without coating the substrate, comprising:
 an immobile liquid holding surface having a coating transfer region;   a coating liquid conveyor for providing the coating liquid at the coating transfer region;   a coating liquid depth controller for controlling the depth of the coating at the coating transfer region to a predetermined depth; and   a substrate conveyor for conveying the microprojections at a predetermined level of immersion through the coating liquid at the coating transfer region, wherein the coating liquid conveyor causes the coating liquid to flow, by force of gravity, over the immobile coating surface, and the immobile liquid holding surface, in the coating transfer region, is substantially planar.   
   
   
       25 . An apparatus for coating an agent-containing liquid onto a plurality of microprojections extending from a surface or edge of a substrate substantially without coating the substrate, comprising:
 an immobile liquid holding surface having a coating transfer region;   a coating liquid conveyor for providing the coating liquid at the coating transfer region;   a coating liquid depth controller for controlling the depth of the coating at the coating transfer region to a predetermined depth; and   a substrate conveyor for conveying the microprojections at a predetermined level of immersion through the coating liquid at the coating transfer region, wherein the coating liquid conveyor causes the coating liquid to flow, by force of gravity, over the immobile coating surface, and the immobile liquid holding surface, in the coating transfer region, is curved.   
   
   
       26 . An apparatus for coating an agent-containing liquid onto a plurality of microprojections extending from a surface or edge of a substrate substantially without coating the substrate, comprising:
 an immobile cylindrically-shaped liquid holding surface having a coating transfer region;   a coating liquid conveyor for providing the coating liquid at the coating transfer region;   a coating liquid depth controller for controlling the depth of the coating at the coating transfer region to a predetermined depth; and   a substrate conveyor for conveying the microprojections at a predetermined level of immersion through the coating liquid at the coating transfer region, wherein the coating liquid conveyor causes the coating liquid to flow, by force of gravity, over the immobile liquid holding surface.   
   
   
       27 . (canceled) 
   
   
       28 . An apparatus for applying an agent-containing coating liquid onto a plurality of microprojections extending from a surface or edge of a substrate substantially without coating said substrate, comprising:
 a rotatable member with a liquid holding surface, said liquid holding surface having a coating transfer region;   a coating liquid conveyor for providing said coating liquid at said coating transfer region;   a coating liquid depth controller for controlling the depth of said coating liquid at said coating transfer region to a predetermined depth; and   a substrate conveyor for conveying said microprojections at a predetermined level of immersion through said coating liquid at said coating transfer region, including a continuous substrate conveyor for continuously conveying a series of said substrates and microprojections through said coating liquid.   
   
   
       29 . An apparatus for applying an agent-containing coating liquid onto a plurality of microprojections extending from a surface or edge of a substrate substantially without coating said substrate, comprising:
 a rotatable member with a liquid holding surface, said liquid holding surface having a coating transfer region;   a coating liquid conveyor for providing said coating liquid at said coating transfer region;   a coating liquid depth controller for controlling the depth of said coating liquid at said coating transfer region to a predetermined depth; and   a substrate conveyor for conveying said microprojections at a predetermined level of immersion through said coating liquid at said coating transfer region, including a continuous substrate conveyor for continuously conveying a series of said substrates and microprojections through said coating liquid, wherein said continuous substrate conveyor comprises a substrate supply roll and a substrate take-up roll.   
   
   
       30 . An apparatus for applying an agent-containing coating liquid onto a plurality of microprojections extending from a surface or edge of a substrate substantially without coating said substrate, comprising:
 a rotatable member with a liquid holding surface, said liquid holding surface having a coating transfer region;   a coating liquid conveyor for providing said coating liquid at said coating transfer region;   a coating liquid depth controller for controlling the depth of said coating liquid at said coating transfer region to a predetermined depth; and   a substrate conveyor for conveying said microprojections at a predetermined level of immersion through said coating liquid at said coating transfer region, including a continuous substrate conveyor for continuously conveying a series of said substrates and microprojections through said coating liquid, wherein said continuous substrate conveyor comprises a substrate supply roll and a substrate take-up roll, further including a substrate guide for positioning said continuous substrate relative to said coating transfer region.   
   
   
       31 . An apparatus for applying an agent-containing coating liquid onto a plurality of microprojections extending from a surface or edge of a substrate substantially without coating said substrate, comprising:
 a rotatable member with a liquid holding surface, said liquid holding surface having a coating transfer region;   a coating liquid conveyor for providing said coating liquid at said coating transfer region;   a coating liquid depth controller for controlling the depth of said coating liquid at said coating transfer region to a predetermined depth;   a substrate conveyor for conveying said microprojections at a predetermined level of immersion through said coating liquid at said coating transfer region, wherein said coating liquid is comprised of a liquid solvent and said agent, said coating liquid having an agent concentration; and   means for controlling said agent concentration selected from the group consisting of, in a temperature controller for controlling the temperature of said coating to a level which reduces evaporative loss of said liquid solvent, a coating atmosphere controller for controlling levels of gaseous solvent in an atmosphere surrounding said coating which reduces evaporative loss of said liquid solvent,   a liquid solvent infusor for infusing liquid solvent into said coating liquid at a rate which compensates for evaporative loss of said liquid solvent, and combinations thereof.   
   
   
       32 . An apparatus for applying an agent-containing coating liquid onto a plurality of microprojections extending from a surface or edge of a substrate substantially without coating said substrate, comprising:
 a rotatable member with a liquid holding surface, said liquid holding surface having a coating transfer region;   a coating liquid conveyor for providing said coating liquid at said coating transfer region;   a coating liquid depth controller for controlling the depth of said coating at said coating transfer region to a predetermined depth;   a substrate conveyor for conveying said microprojections at a predetermined level of immersion through said coating liquid at said coating transfer region, wherein said coating liquid is comprised of a liquid solvent and said agent, said coating liquid having an agent concentration; and   means for controlling said agent concentration selected from the group consisting of, a temperature controller for controlling the temperature of said coating to a level which reduces evaporative loss of said liquid solvent, a coating atmosphere controller for controlling levels of gaseous solvent in an atmosphere surrounding said coating which reduces evaporative loss of said liquid solvent a liquid solvent infusor for infusing liquid solvent into said coating liquid at a rate which compensates for evaporative loss of said liquid solvent, and combinations thereof, and   wherein said liquid solvent comprises water, said temperature is less than about 10° C., and said atmosphere has a relative humidity greater than about 60%.