Intradermal delivery of substances

Abstract

Methods for ID delivery of drugs and other substances to humans or animals are provided. The methods employ small gauge needles, especially microneedles, placed in the intradermal space to deliver the substance to the intradermal space as a bolus or by infusion. It has been discovered that the placement of the needle outlet within the skin and the exposed height of the needle outlet are critical for efficacious delivery of active substances via small gauge needles to prevent leakage of the substance out of the skin and to improve absorption within the intradermal space. Delivery devices which place the needle outlet at an appropriate depth in the intradermal space and control the volume and rate of fluid delivery to provide accurate delivery of the substance to the desired location without leakage are also provided herein.

1 . A method for delivering a substance into skin comprising delivering the substance into an intradermal space within the skin through a small gauge needle inserted into the intradermal space, wherein an outlet of the needle is inserted at a depth within the skin such that leakage of the substance to the surface of the skin is substantially prevented. 
     
     
         2 . The method of  claim 1  wherein the needle is selected from the group consisting of microneedles, catheter needles, and injection needles. 
     
     
         3 . The method of  claim 1  wherein a single needle is inserted. 
     
     
         4 . The method of  claim 1  wherein multiple needles are inserted. 
     
     
         5 . The method of  claim 1  wherein the substance is a liquid delivered by pressure directly on the liquid. 
     
     
         6 . The method of  claim 1  wherein a hormone is delivered. 
     
     
         7 . The method of  claim 6  wherein the hormone is selected from the group consisting of insulin and PTH. 
     
     
         8 . The method of  claim 1  wherein the substance is infused. 
     
     
         9 . The method of  claim 1  wherein the substance is injected as a bolus. 
     
     
         10 . The method of  claim 1  wherein the needle is about 300 μm to 2 mm long. 
     
     
         11 . The method of  claim 10  wherein the needle is about 500 μm to 1 mm long. 
     
     
         12 . The method of  claim 1  wherein the outlet is at a depth of about 250 μm to 2 mm when the needle is inserted. 
     
     
         13 . The method of  claim 12  wherein the outlet is at a depth of about 750 μm to 1.5 mm when the needle is inserted. 
     
     
         14 . The method of  claim 12  wherein the outlet has an exposed height of about 0 to 1 mm. 
     
     
         15 . The method of  claim 14  wherein the outlet has an exposed height of about 0 to 300 μm. 
     
     
         16 . The method of  claim 1  wherein delivery rate or volume delivered is controlled by spacing of multiple needles, needle diameter or number of needles. 
     
     
         17 . A needle for intradermal delivery of a substance into skin comprising means for limiting penetration of the needle into the skin and an outlet positioned such that when the needle is inserted into the skin to a depth determined by the penetration limiting means, leakage of the substance to the surface of the skin is substantially prevented. 
     
     
         18 . The needle of  claim 17  wherein the outlet is at a depth of about 500 μm to 2 mm when the needle is inserted into the skin. 
     
     
         19 . The method of  claim 18  wherein the outlet is at a depth of about 750 urn to 1.5 mm when the needle is inserted into the skin. 
     
     
         20 . The needle of  claim 17  which is about 300 μm to 2 mm long. 
     
     
         21 - 24 . (canceled)