Injection apparatus and method of using same

Abstract

The present invention relates to an apparatus and method for using the apparatus for injecting an agent into a tissue, particularly into thin tissues such as the sclera of the eye. The invention provides an apparatus and method for effectively imbedding a needle into a tissue at a predetermined penetration approach angle and penetration distance thereby reducing the risk of penetrating the full thickness of the tissue. The invention includes a support element and a needle guide platform disposed on the support element with an external support surface and a channel extending therethrough and terminating in an aperture at the support surface. A needle disposed in the channel is axially movable along an axis of injection through the channel. The needle is movable from a first retracted position to an extended position corresponding to the penetration distance, along the axis of injection. The axis of injection forms a penetration approach angle of up to about 60° with a tangent of the support surface at a point of intersection of the axis of injection with the projection of the support surface across the aperture.

We claim:  
     
         1 . An apparatus for delivering an agent into a tissue, the apparatus comprising: 
 a support element;    a needle guide platform disposed on said support element and having an external support surface and a channel extending therethrough, the channel terminating in an aperture at the support surface;    a needle having a first end and a second end, said needle including a sidewall defining an outlet in said needle and an inlet disposed in said needle, the inlet being in fluid flow communication with the outlet.    
     
     
         2 . An apparatus according to    claim 1   , wherein said needle is axially movable through said channel from a retracted position to an extended position.  
     
     
         3 . An apparatus according to    claim 2   , further comprising: 
 an actuator for moving said needle through said channel from the retracted position to the extended position.    
     
     
         4 . An apparatus according to    claim 1   , further comprising: 
 a medicament reservoir disposed on said support element and in fluid flow communication with the inlet of said needle.    
     
     
         5 . An apparatus according to    claim 1   , wherein the external support surface is shaped to substantially conform to an external surface of a sclera of an eye.  
     
     
         6 . An apparatus according to    claim 1   , wherein the first end of said needle comprises a sharpened point.  
     
     
         7 . A method for injection comprising: 
 placing a needle into a tissue, the tissue having a first surface and a second surface defining a tissue thickness, at a penetration distance of greater than about the tissue thickness but such that even if extended the needle could not intersect the second tissue surface; and    inserting an agent into the tissue through an outlet defined by a sidewall of the needle, such that the agent exiting the outlet is in an orientation towards one of the first and second surface of the tissue in said needle when the needle is placed into the tissue.    
     
     
         8 . A method for injecting an agent into a target tissue, the target tissue having a first surface and a second surface defining a tissue thickness, said method comprising: 
 disposing a needle in an injection apparatus, the apparatus including a support element, a needle guide platform disposed on said support element and having an external support surface and a channel extending therethrough, a needle disposed in said channel and movable along an axis of injection through the channel, the needle having a first end and a second end and including a sidewall defining an outlet in the needle and an inlet disposed in the needle, the inlet being in fluid flow communication with the outlet;    placing the needle in fluid flow communication with a medicament reservoir;    positioning the injection apparatus adjacent a tissue surface;    advancing the needle outwardly through the channel;    imbedding the needle into the target tissue such that the outlet is adjacent to, and oriented in a direction substantially facing, one of the first and second surface of the tissue; and    transferring the agent into the tissue.    
     
     
         9 . A method according to    claim 8   , wherein the needle is imbedded into the target tissue at a penetration distance of greater than about the target tissue thickness.  
     
     
         10 . A method according to    claim 9   , wherein even if the needle were extended, it could not intersect the second target tissue surface.  
     
     
         11 . A method according to    claim 9   , wherein the needle is imbedded into the target tissue at a penetration distance of about 1.5 mm to about 4 mm.  
     
     
         12 . A method according to    claim 9   , wherein the needle is imbedded into the target tissue at a penetration distance of about 2 mm to about 3 mm.  
     
     
         13 . A method according to    claim 8   , wherein in the transferring step, the agent is transferred at a rate of about 1 to about 10 microliters/second.  
     
     
         14 . A method according to    claim 13   , wherein in the transferring step, the agent is transferred at a rate of about 1 to about 4 microliters/second.  
     
     
         15 . A method according to    claim 14   , wherein in the transferring step, the agent is transferred at a rate of about 4 microliters/second.  
     
     
         16 . An apparatus for injecting an agent into a tissue comprising: 
 a support element having a distal end and a proximal end;    a needle guide platform disposed on the distal end of said support element and having an external support surface and a channel extending therethrough, the channel terminating in an aperture at the support surface;    a needle disposed in said channel and axially movable through said channel from a retracted position to an extended position, said needle having a first end and a second end, said needle including a sidewall defining an outlet in said needle and an inlet disposed in said needle, the inlet being in fluid flow communication with the outlet, said needle extending from said aperture when moving from the retracted position to the extended position;    whereby, an axis of injection of said needle forms an acute penetration approach angle of up to about 60° with a tangent of the support surface at a point of intersection of a longitudinal axis of said needle with a projection of the support surface across the aperture.    
     
     
         17 . An apparatus according to    claim 16   , wherein the first end of said needle comprises a sharpened point.