Dissolvable microneedles for skin treatment

Abstract

A skin treatment device is provided including bioerodible polymeric microneedles which are designed to more effectively deliver beneficial agents to the skin. The device includes a flexible substrate and an arrangement, for example, an array, of microneedles projecting from the substrate.

What is claimed is: 
     
         1 . A device effective to deliver a beneficial agent to the skin, the device comprising:
 a substrate; and   an arrangement of microneedles projecting from the substrate;   the arrangement comprising first microneedles having a first length and second microneedles having a second length different from the first length;   the first and second microneedles comprising a mixture of a polymeric material and an active agent beneficial to skin.   
     
     
         2 . The device of  claim 1  wherein the polymeric material comprises hyaluronic acid. 
     
     
         3 . The device of  claim 2  wherein the polymeric material comprises crosslinked hyaluronic acid. 
     
     
         4 . The device of  claim 1  wherein the first length is at least about 20% greater in length than the second length. 
     
     
         5 . The device of  claim 1  wherein the first length is at least about 40% greater in length than the second length. 
     
     
         6 . The device of  claim 1  wherein the first length is at least about 60% greater in length than the second length. 
     
     
         7 . The device of  claim 1  wherein the first length is at least about 80% greater in length than the second length. 
     
     
         8 . The device of  claim 1  wherein the arrangement is in the form of an array in which the first and second microneedles are arranged in an alternating fashion. 
     
     
         9 . A method of treating skin comprising applying the device of  claim 1  to a region of skin to be treated in a manner capable of causing the first and second microneedles to penetrate the stratum corneum. 
     
     
         10 . The method of  claim 8  further comprising drawing the region of skin to be treated toward the device using suction or a vacuum. 
     
     
         11 . A skin treatment assembly comprising:
 a first patch having a first shape for covering a portion of a face to the treated and including a first array of microneedles;   a second patch having a second shape different from the first shape for covering another portion of a face to be treated and including a second array of microneedles different from the first array.   
     
     
         12 . The assembly of  claim 11  wherein the first array comprises microneedles having a first length and the second array comprises microneedles having a second length different from the first length. 
     
     
         13 . The assembly of  claim 11  wherein the first array comprises microneedles having a first spacing between adjacent microneedles and the second array comprises microneedles having a second spacing between adjacent microneedles the second spacing being different from the first spacing. 
     
     
         14 . The assembly of  claim 11  wherein the microneedles comprise a mixture of a polymeric material and an active agent beneficial to skin. 
     
     
         15 . The device of  claim 14  wherein the polymeric material comprises hyaluronic acid.