Device and method for enhancing skin piercing by microprotrusions

Abstract

A device and method for enhancing skin piercing by microprotrusions involves pre-stretching the skin to enhance pathway formation when the microprotrusions are pressed into the skin. An expandable device includes skin engaging opposite ends that contact the skin surface so that when the device is expanded the skin is stretched. The skin is placed under a tension of about 0.01 to about 10 megapascals, preferably about 0.05 to 2 megapascals. The device has a plurality of microprotrusions which penetrate the skin while the skin is being stretched by the expanded device. Another stretching device employs suction for skin stretching.

1 . An apparatus for applying to a body surface, comprising: 
 an expandable member having a body surface engaging first portion and a body surface engaging second portion, said body surface engaging first and second portions being adapted to apply a tension of about 0.01 to about 10 M Pa to the body surface when the member is expanded; and    a microprojection member having a plurality of microprotrusions for penetrating the body surface, said plurality of microprotrusions being disposed between said first portion and said second portion of said expandable member.    
   
   
       2 . The apparatus of  claim 1 , further comprising and agent-containing reservoir located between said body surface engaging first and second portions.  
   
   
       3 . The apparatus of  claim 2 , wherein said reservoir is located in a housing and wherein said plurality of microprotrusions extend from a skin proximal side of said housing.  
   
   
       4 . The apparatus of  claim 3 , wherein said housing is wedge-shaped and contacts surfaces on said body surface engaging first and second portions to expand said expandable member when said housing is inserted between said body surface engaging first and second portions.  
   
   
       5 . The apparatus of  claim 3 , wherein said housing is shaped to expand said expandable member when said housing is rotated in a space between said body surface engaging first and second portions.  
   
   
       6 . The apparatus of  claim 1 , further comprising: 
 a retainer that initially holds said body surface engaging first and second portions in a first position; and    a biasing member for urging said body surface engaging first portion away from said body surface engaging second portion when said retainer is removed.    
   
   
       7 . The apparatus of  claim 1 , further comprising: 
 means for holding said expandable member in an expanded state after said member has been expanded.    
   
   
       8 . The apparatus of  claim 7 , wherein said holding means holds said expandable member in said expanded state in a first direction and wherein said housing is wedge-shaped and contacts surfaces on said body surface engaging first and second portions to expand said member in a second direction.  
   
   
       9 . The apparatus of  claim 1 , wherein said plurality of microprotrusions comprise: 
 a first sheet member having a first set of microprotrusions extending outward therefrom, said first sheet member being in communication with said body surface engaging first portion; and    a second sheet member having a second set of microprotrusions extending outward therefrom, said second sheet member being in communication with said body surface second portion, whereby when said expandable member is expanded said first sheet member moves in a direction parallel to said second sheet member and away from said body surface engaging said second portion.    
   
   
       10 . The apparatus of  claim 1 , wherein said body surface engaging first portion and said body surface engaging second portion comprise rotatable members pivotally mounted on a base.  
   
   
       11 . The apparatus of  claim 1 , wherein said plurality of microprotrusions are arranged in a row and are adapted to be moved over the body surface to form a plurality of elongated slits therein.  
   
   
       12 . A transdermal agent delivery devices comprising: 
 a skin stretching device for stretching skin by applying a tension of about 0.01 to about 10 M Pa to the skin; and    an agent containing member having an array of microprotrusions, wherein said skin stretching device is configured to stretch the skin of a subject and maintain said skin in a stretched state during penetration of said skin by said microprotrusions.    
   
   
       13 . The device of  claim 12 , wherein said skin stretching device includes first and second skin engaging portions and means for moving said first and second skin engaging portions away from each other to stretch said skin.  
   
   
       14 . The device of  claim 13 , wherein said first and second skin engaging portions slide apart to stretch said skin.  
   
   
       15 . The device of  claim 13 , wherein said first and second skin engaging portions rotate to stretch said skin.  
   
   
       16 . The device of  claim 12 , wherein said skin stretching device includes a suction chamber having an opening that is pressed against said skin to stretch said skin, and wherein said agent containing member is movable within said suction chamber to pierce said skin.  
   
   
       17 . The device of  claim 16 , wherein said suction chamber comprises an interior space of a tubular member that is provided with a suction for drawing said skin into said tubular member.  
   
   
       18 . The device of  claim 12 , wherein said skin stretching device includes: at least one channel having an open side for contacting said skin; and means for applying a suction to said channel to draw said skin into said channel and stretch skin adjacent to said channel.  
   
   
       19 . The device of  claim 18 , wherein said agent containing member is movable within said skin stretching device to pierce said stretched skin between opposing portions of the at least one channel.  
   
   
       20 - 33 . (canceled)