Microneedle arrays formed from polymer films

Abstract

An active agent can be administered transdermally to a patient by using a transdermal patch that has microneedles that are compositionally homogenous with a base layer. The transdermal patch can contain an active agent that can be delivered to a skin surface of a subject when the patch is applied.

1 . A method of administering an active agent transdermally comprising:
 providing a transdermal patch having a polymer base layer with microneedles projecting from a surface thereof, wherein the microneedles are compositionally homogenous with the polymer base layer, and wherein said transdermal patch contains an active agent; and   applying said transdermal patch to a skin surface of a subject.   
     
     
         2 . The method of  claim 1 , wherein the active agent is delivered over a sustained period of time. 
     
     
         3 . The method of  claim 1 , wherein the polymer base layer of the transdermal patch is removed from the skin surface of the subject while leaving the microneedles embedded in the skin surface. 
     
     
         4 . The method of  claim 1 , wherein the microneedles continue to deliver the active agent after the polymer base layer is removed from the skin surface of the subject. 
     
     
         5 . The method of  claim 4 , wherein the microneedles are hollow. 
     
     
         6 . The method of  claim 1 , wherein the microneedles are solid. 
     
     
         7 . The method of  claim 6 , wherein the active agent is loaded onto an exterior surface of the microneedles. 
     
     
         8 . The method of  claim 1 , wherein the active agent is included in the polymer base layer. 
     
     
         9 . The method of  claim 1 , wherein the microneedles are regularly spaced on the polymer base layer. 
     
     
         10 . The method of  claim 5 , wherein the active agent is loaded into the microneedles. 
     
     
         11 . The method of  claim 1 , wherein the transdermal patch contains two or more active agents. 
     
     
         12 . The method of  claim 1 , wherein the active agent is incorporated into the microneedles. 
     
     
         13 . The method of  claim 1 , wherein the polymer is bio-absorbable. 
     
     
         14 . The method of  claim 1 , wherein the polymer is biodegradable. 
     
     
         15 . The method of  claim 1 , further comprising removing said transdermal patch from the skin surface of a subject. 
     
     
         16 . The method of  claim 15 , wherein the microneedles remain embedded in the skin surface after removal of the transdermal patch. 
     
     
         17 . The method of  claim 1 , wherein the polymer base layer has a thickness from about 0.5 mm to about 5 mm. 
     
     
         18 . The method of  claim 1 , wherein the polymer is selected from the group consisting of polyvinyl alcohol, polyacrylates, polymers of ethylene-vinyl acetates, other acyl substituted cellulose acetates, polyurethanes, polystyrenes, polyvinyl chloride, polyvinyl fluoride, polyethylene oxide, chlorosulphonate polyolefins, poly(vinyl imidazole), poly(valeric acid), poly butric acid, poly lactides, polyglycolides, polyanhydrides, polyorthoesters, polysaccharides, gelatin, and mixtures and copolymers thereof. 
     
     
         19 . The method of  claim 1 , wherein the active agent is a nucleic acid. 
     
     
         20 . The method of  claim 19 , wherein the nucleic acid is single stranded DNA, double stranded DNA, single stranded RNA, double stranded RNA, or plasmid. 
     
     
         21 . A method for preparing a microneedle array comprising:
 (i) applying a polymer solution onto a substrate to form a base layer having a surface that is in contact with the substrate and an exposed surface that is not in contact with the substrate;   (ii) contacting the exposed surface of the base layer with an array of pins for a period of time before retracting the array of pins from the exposed surface of the base layer to form the microneedle array on the exposed surface of the base layer wherein the array of pins is retracted at a rate of 0.1 mm/s to 100 mm/s with an a heated airflow of 0.1 m/s to 10 m/s at a temperature of 0° C. to 100° C.   
     
     
         22 . The method of  claim 21  further comprising the step of incorporating an active agent into the microneedle array. 
     
     
         23 . The method of  claim 21  wherein the microneedle array is incorporated into a transdermal patch.