Microneedle arrays and methods of manufacturing the same

Abstract

Microneedle arrays, methods of manufacturing microneedles and methods of using microneedle arrays. The microneedles in the microneedle arrays may be in the form of tapered structures that include at least one channel formed in the outside surface of each microneedle. The microneedles may have bases that are elongated in one direction. The channels in microneedles with elongated bases may extend from one of the ends of the elongated bases towards the tips of the microneedles. The channels formed along the sides of the microneedles may optionally be terminated short of the tips of the microneedles. The microneedle arrays may also include conduit structures formed on the surface of the substrate on which the microneedle array is located. The channels in the microneedles may be in fluid communication with the conduit structures. One manner of using microneedle arrays of the present invention is in methods involving the penetration of skin to deliver medicaments or other substances and/or extract blood or tissue.

1 . A method of delivering a microneedle array to a skin impact site, the method comprising: 
 positioning a microneedle array proximate a delivery site, the microneedle array comprising a plurality of microneedles protruding from a surface;    applying an impact force to the microneedle array over a period of less than about 1 second, wherein the plurality of microneedles are driven through the stratum corneum at the skin impact site.    
   
   
       2 . A method according to  claim 1 , wherein the period is less than about 500 milliseconds.  
   
   
       3 . A method according to  claim 1 , wherein the period is less than about 300 milliseconds.  
   
   
       4 . A method according to  claim 1 , wherein applying the impact force to the microneedles array comprises accelerating the microneedle array towards the skin impact site.  
   
   
       5 . A method according to  claim 1 , wherein the microneedle array is in contact with the skin impact site before applying the impact force to the microneedle array.  
   
   
       6 . A method according to  claim 1 , further comprising removing the microneedle array from contact with the skin impact site within about 1 second after the plurality of microneedles are driven through the stratum corneum at the skin impact site.  
   
   
       7 . A method according to  claim 1 , further comprising retaining the microneedle array in contact with the skin impact site for about 2 seconds or more after the plurality of microneedles are driven through the stratum corneum at the skin impact site.  
   
   
       8 . A method according to  claim 1 , wherein the impact force has a maximum of about 40 N/cm 2  or less.  
   
   
       9 . A method according to  claim 1 , wherein the impact force has a maximum of about 20 N/cm 2  or less.  
   
   
       10 . A method according to  claim 1 , further comprising drawing a vacuum at the skin impact site after the plurality of microneedles are driven through the stratum corneum at the skin impact site.  
   
   
       11 . A method according to  claim 1 , further comprising locating an indicator in contact with the skin impact site after the plurality of microneedles are driven through the stratum corneum at the skin impact site.  
   
   
       12 . A method according to  claim 1 , wherein the method further comprises: 
 locating an indicator in contact with the skin impact site after the plurality of microneedles are driven through the stratum corneum at the skin impact site; and    drawing a vacuum at the skin impact site after the plurality of microneedles are driven through the stratum corneum at the skin impact site.    
   
   
       13 . A microneedle array delivery device comprising: 
 a microneedle array comprising a plurality of microneedles protruding from a surface;    a driver operably connected to the microneedle array, wherein the driver comprises stored energy;    wherein release of the stored energy results in application of an impact force to the microneedle array over a period of less than about 1 second.    
   
   
       14 . A device according to  claim 13 , wherein the driver comprises at least one mechanical spring.  
   
   
       15 . A method according to  claim 13 , wherein the driver comprises at least one resilient member.  
   
   
       16 . A method according to  claim 13 , wherein the driver comprises a compressed fluid.