referring now to the drawing , there is seen in a distal end of a needle 10 having a pointed , distal end 10 a for directing into the tissue of a target surgical site of a mammalian organism , for example a human eye . the opposite , proximal end of the needle may be of any desired configuration for manual or machine manipulation of needle 10 consistent with the intended uses of needle 10 set forth herein ( not shown ). needle 10 may be made of any suitable material for injection within a mammalian organism , some examples of which include titanium , stainless steel , ceramic , and polymer . the diameter of needle 10 is sized to enable direct injection of needle 10 within the delicate tissues of a human eye . a drug implant is indicated by reference numeral 12 and is illustrated herein in the shape of a cylinder having an outer diameter less than the diameter of needle 10 adjacent distal end 10 a thereof , although the drug implant may be of other shapes as desired . drug implant 12 is a slow - release implant capable of controlled release of a drug to the implant site . needle 10 is the vehicle for delivering implant 12 to the implant site . more particularly , needle 10 is seen to include a lateral opening 14 therein adjacent distal end 10 a thereof . opening 14 serves to releasably hold drug implant 12 therein until the distal end 10 a of needle 10 reaches the implant site in the organism , at which time drug implant 12 is released from opening 14 . once drug implant 12 is released at the implant site , needle 10 may be withdrawn from the organism and either sterilized for subsequent use or discarded in single - use designs of needle 10 . opening 14 may be of any desired configuration , but is preferably configured to match the shape of the drug implant 12 releasably held therein . as seen in fig3 and 4 , a protective cover 16 may be provided in coaxial , sliding engagement with needle 10 . covering 16 is selectively movable along the shaft of needle 10 from the open position seen in fig3 to the closed position seen in fig4 wherein drug implant 12 is prevented from falling free of opening 14 until the target site is reached , at which time covering 16 may be moved in the opposite direction to the open position . an extensible rod ( not shown ) may be attached to covering 16 to selectively move it between the open and closed positions . attention is now turned to fig5 which shows a first embodiment of an implant release mechanism . in this embodiment ; a center bore 18 is provided as an axial extension of opening 14 wherein a spring 20 may be positioned to apply a biasing force against drug implant 12 such that implant 12 is forcibly held between the spring and the distal end wall 14 a of opening 14 . a longitudinally extending rod 22 may be attached to the distal end 20 a of spring 20 whereby rod 22 may be retracted in a direction opposite distal needle end 10 a to release the biasing force of spring 20 , thereby allowing release of implant 12 from needle 10 at the implant site . [ 0036 ] fig6 shown a second embodiment wherein drug implant 12 is engaged in opening 14 by friction - fit at opposite ends 12 a , 12 b thereof . as seen in the cross - section view of fig7 drug implant 12 which is cylindrical in this embodiment , is engaged in opening 14 by the three planar walls 14 b , 14 c , and 14 d of opening 14 frictionally engaging the cylindrical side wall 12 ′ thereof . although no release mechanism is shown in fig6 or 7 , any of the release mechanisms described herein may be used in combination with any of the securing mechanisms described herein which will be detailed more fully below . [ 0037 ] fig8 and 9 show another embodiment of a securing and release mechanism for implant 12 . to load the implant 12 in opening 14 , longitudinally extending rod 24 is retracted to the position shown in fig8 whereby a clearance 14 ′ is provided in opening 14 to allow easy insertion of implant 12 therein . once implant 12 is inserted into opening 14 , rod 24 may be moved in the opposite direction toward distal end 10 a until the distal end of the rod 24 a engages the proximal end 12 a of the implant 12 . rod 24 and the axial bore 10 b in which rod 24 extends may be provided with latch 26 and slot 28 , respectively , such that rod 14 may be locked into the engaged position seen in fig9 until the implant site is reached , at which time latch 26 may be disengaged from slot 28 ( e . g ., by rotating rod 24 ). a manually operable push - tab 30 may be attached to rod 24 and lie exteriorly of needle 10 to allow easy one - touch manipulation of rod 24 . referring to fig1 and 11 , a release mechanism is shown comprising a shaft 32 reciprocally mounted in axial bore 10 e formed in needle 10 . shaft 32 includes an angled distal end 32 a which may be moved to the secured position wherein end 32 a is in just - touching relation to the proximal end of implant 12 as seen in fig1 . to release implant 12 at the implant site , shaft 32 is moved further toward distal end 10 a whereupon the leading tip of end 32 a wedges beneath implant 12 causing implant 12 to dislodge from opening 14 as seen in fig1 . in yet a further embodiment of implant release mechanism , the rod 24 of the embodiment of fig8 and 9 is used in combination with a spring 34 located within opening 14 . in the load / release position shown in fig1 , spring 34 is unbiased and rod 24 is retracted . in this position , implant 12 may be inserted into opening 14 and pressed against spring 34 to put spring 34 in tension . in the fully inserted position of implant 12 seen in fig1 , spring 34 is fully tensioned and applying an outward biasing force against implant 12 . while the implant and spring are held in this position ( e . g ., by pressing with a finger ), rod 24 is extended until end 24 a thereof is engaged against the proximal end 12 a of implant 12 . rod 24 may be locked in place as explained above with regard to fig8 and 9 , at which time implant 12 is held tightly within opening 14 since the force of end 24 a against implant 12 is stronger than the biasing force of spring 24 . once needle 10 has been injected within the organism and end 10 a thereof is at the implant site , the user releases and retracts rod 24 to the position seen in fig1 , at which time the force against implant end 12 a is removed and the biasing force of spring 34 takes over to force implant 12 from opening 14 . needle 10 may then be retracted from the implant site , leaving implant 12 in place . it will thus be appreciated that the present invention provides an improved injection device for delivering slow - release drug implants to the inside body of an organism . since the drug implant is both held and released at the distal end of the needle , there is no need for a cannula delivery of the implant which obviates that many problems associated therewith as explained in the background section hereof .
a device for delivering a drug implant to an implant site comprises a needle having a lateral opening in which the drug implant is releasably held . once at the implant site , the drug implant is released directly form the opening . the invention obviates the need for a cannula through which a drug implant is delivered , and therefore obviates the many problems associated with a cannula - type delivery device .