Methods and devices for delivering agents across biological barriers

Abstract

The invention provides for microneedle devices for delivering agents across biological barriers. The microneedles include agent reservoirs integrated into the bodies of the microneedles, themselves.

1 . A device for delivering an agent across a biological barrier comprising: 
 a first microneedle;    a first reservoir integrated into the microneedle for holding the agent.    
   
   
       2 . The device of  claim 1 , wherein the biological barrier is skin.  
   
   
       3 . The device of  claim 1 , wherein the first reservoir comprises an opening through one of the width and depth of the microneedle.  
   
   
       4 . The device of  claim 1 , wherein the first reservoir comprises a depression in the microneedle.  
   
   
       5 . The device of  claim 1 , wherein the first reservoir takes up a substantial portion of the volume of the first microneedle.  
   
   
       6 . The device of  claim 5 , wherein the portion is between about 5% and about 70% of the volume of the first microneedle.  
   
   
       7 . The device of  claim 5 , wherein the portion is about 20% -50% of the volume of the first microneedle.  
   
   
       8 . The device of  claim 1 , wherein the first microneedle comprises one of stainless steel and titanium.  
   
   
       9 . The device of  claim 1 , wherein the first microneedle is between about 150 μm to about 3000 μm long.  
   
   
       10 . The device of  claim 1 , wherein the first microneedle is between about 300 μm to about 1500 μm long.  
   
   
       11 . The device of  claim 1 , wherein the first microneedle is about 10 μm to about 2000 μm wide.  
   
   
       12 . The device of  claim 1 , wherein the first microneedle is about 100 μm to about  500 μm wide.    
   
   
       13 . The device of  claim 1 , wherein the agent is suitable for intradermal delivery.  
   
   
       14 . The device of  claim 1 , wherein the agent contains a drug.  
   
   
       15 . The device of  claim 1 , wherein the agent contains a vaccine.  
   
   
       16 . The device of  claim 1 , wherein the reservoir is filled with the agent.  
   
   
       17 . The device of  claim 1 , comprising a second microneedle having a second reservoir integrated into the second microneedle.  
   
   
       18 . The device of  claim 17 , wherein the first reservoir contains a first agent and the second reservoir contains the same agent.  
   
   
       19 . The device of  claim 17 , wherein the first reservoir contains a first agent and the second reservoir contains a different agent.  
   
   
       20 . The device of  claim 17 , wherein the first microneedle extends from a first base element, the second microneedle extends from a second base element, and wherein the first and second base elements are coupled to a common substrate.  
   
   
       21 . The device of  claim 1 , comprising a depth guard for limiting the depth to which to the first microneedle can pierce the skin of a user.  
   
   
       22 . The device of  claim 21 , wherein the depth guard extends from one of the first microneedle, a substrate from which the first microneedle extends, and a base element from which the first microneedle extends.  
   
   
       23 . The device of  claim 21 , comprising a base element having a proximal end and a distal end, the base element being wider at its proximal end than at distal end, wherein: 
 the first microneedle extends from the distal end of the base element, and    the depth guard extends beyond the base element towards the distal end of the first microneedle.    
   
   
       24 . The device of  claim 1 , comprising one of a biodegradable stent, wherein the first microneedle is coupled to the biodegradable stent for delivering the agent across a vascular barrier.  
   
   
       25 . The device of  claim 1 , comprising a surgical tool, wherein the microneedle is coupled to the surgical tool for delivering the agent across an internal biological barrier.  
   
   
       26 . A method of manufacturing a device for delivering an agent across a biological barrier: 
 providing a microneedle having an integrated agent reservoir; and    filling the integrated agent reservoir with the agent.    
   
   
       27 . The method of manufacturing a device for transdermal delivery of an agent of  claim 26  wherein filling the integrated agent reservoir comprises dipping the microneedle into a solution containing the agent.  
   
   
       28 . The method of manufacturing a device for transdermal delivery of an agent of  claim 26  wherein filling the integrated agent reservoir comprises depositing a predetermined volume of a solution containing the agent into the integrated agent reservoir.  
   
   
       29 . The method of manufacturing a device for transdermal delivery of an agent of  claim 26  wherein filling the integrated agent reservoir comprises applying a hydrophilic compound to the interior of the integrated agent reservoir and applying a hydrophobic compound to a remainder of the microneedle.  
   
   
       30 . The method of manufacturing a device for transdermal delivery of an agent of  claim 26  further comprising 
 providing a second microneedle having a second integrated agent reservoir;    coupling the first microneedle and the second microneedles to a substrate; and    filling the second integrated agent reservoir with the agent.    
   
   
       31 . A method of delivering an agent transdermally comprising: 
 providing a microneedle having an integrated agent reservoir filled with the agent;    applying the microneedle against the skin of a patient, thereby piercing the skin and positioning the integrated reservoir beneath the surface of the skin.    
   
   
       32 . A device for transdermal agent delivery comprising: 
 a substrate;    a plurality of microneedles extending from corresponding base elements coupled to the substrate, wherein the microneedles include openings, which take up between 20-50% of the volume of a corresponding microneedle, and which define integrated agent reservoirs; and    a depth guard extending from at least one of the base elements for limiting the depth to which the plurality of microneedles can be inserted into a surface.    
   
   
       33 . A method of delivering an agent transdermally comprising: 
 providing a plurality of microneedles coupled to a substrate, wherein at least one of the plurality of microneedles includes an opening defining an integrated reservoir holding the agent;    applying the substrate to the skin of a patient, thereby puncturing the skin to a depth allowed by a depth guard coupled to at least one of the microneedles such that the integrated reservoir is below the surface of the skin.