Soft tip cannula with retractable tip protector

Abstract

Injector devices and methods for using them to deliver medicament into a patient's body, e.g., sub-retinally within an eye, are provided. The injector includes an injector cannula having a soft injector tip. A retractable tip protector tube is slidably disposed on the flow cannula between an extended position in which the tip protector tube covers the entire injector tip, and a retracted position in which the tip protector tube is retracted proximally thereby exposing at least part of the injector tip. Accordingly, the tip protector tube protects the injector tip from being damaged while advancing the injector tip to a target injection site.

What is claimed is: 
     
         1 . An injector device for delivering a medicament into a patient's body, comprising:
 a housing containing the medicament and including an outlet end for delivering the medicament from the housing;   an injector fitting comprising a first end coupled to the outlet end of the housing and a second end;   a flow cannula comprising a proximal end attached to the second end of the injector fitting and a distal end extending distally from the injector fitting;   a flexible injector tip extending distally from the distal end of the flow cannula;   a hub slidably coupled to the injector fitting; and   a tip protector tube permanently attached to and extending distally from the hub and slidably disposed over the flow cannula, the hub slidable on the injector fitting to cause the tip protector tube to slide relative to the flow cannula from an extended position in which the tip protector tube covers the entire injector tip, and a retracted position in which the tip protector tube is retracted proximally relative to the injector tip thereby exposing at least part of the injector tip from the tip protector tube, the tip protector tube being substantially stiffer than the injector tip.   
     
     
         2 . The injector device of  claim 1 , wherein the outlet end and the injector fitting comprise connectors for removably coupling the injector fitting to the housing. 
     
     
         3 . The injector device of  claim 2 , wherein the connectors comprise mating Luer hubs. 
     
     
         4 . The injector device of  claim 1 , wherein the hub and the injector fitting have a sliding interface which rotationally aligns the hub and the injector fitting and prevents relative rotation of the hub and injector fitting. 
     
     
         5 . The injector cannula of  claim 4 , wherein the sliding interface comprises one or more longitudinal slots on one of the hub and the injector fitting and one or more longitudinal ridges or fins on the other of the hub and the injector fitting, which are slidably received in respective slots of the one or more longitudinal slots. 
     
     
         6 . The injector cannula of  claim 1 , further comprising a flange on a proximal end of the hub. 
     
     
         7 . The injector cannula of  claim 1 , wherein the hub and the injector fitting comprise features that retain the hub and tip protector tube separately in the extended position and the retracted position, respectively. 
     
     
         8 . The injector cannula of  claim 7 , wherein the features comprise one or more snaps on the hub and a plurality of notches spaced apart longitudinally on the injector fitting, the one or more snaps configured to interface with respective notches on the injector fitting to retain the hub and tip protector tube separately in the extended position and the retracted position. 
     
     
         9 . The injector cannula of  claim 1 , wherein the injector device is one of a syringe, and a self-powered injector. 
     
     
         10 . An injector cannula for delivering a medicament into a patient's body, comprising:
 an elongate tubular member comprising a first end including a connector for coupling the injector cannula to an injector device and a second end;   a flow cannula comprising a proximal end attached to the second end of the tubular member and a distal end extending distally from the injector fitting;   a flexible injector tip extending distally from the distal end of the flow cannula;   a hub slidably coupled to the second end of the tubular member; and   a tip protector tube permanently attached to and extending distally from the hub and slidably disposed over the flow cannula, the hub slidable on the second end of the tubular member to cause the tip protector tube to slide relative to the flow cannula from an extended position in which the tip protector tube covers the entire injector tip, and a retracted position in which the tip protector tube is retracted proximally relative to the injector tip thereby exposing at least part of the injector tip from the tip protector tube, the tip protector tube being substantially stiffer than the injector tip.   
     
     
         11 . An injector device for delivering a medicament into a patient's body, comprising:
 a housing containing the medicament;   an injector fitting comprising a first end coupled to the housing and a second end;   a flow cannula comprising a proximal end attached to the second end of the injector fitting, a distal end, and a lumen for delivering the medicament from the housing;   a flexible injector tip disposed on the distal end of the flow cannula and extending distally from the flow cannula;   a hub slidably disposed on the injector fitting; and   a tip protector tube permanently attached to the hub, the tip protector tube slidable on the flow cannula from an extended position in which the tip protector tube covers the entire injector tip, and a retracted position in which the tip protector tube is retracted proximally relative to the injector tip, thereby exposing at least part of the injector tip from the tip protector tube, the tip protector tube being substantially stiffer than the injector tip.   
     
     
         12 . The injector device of  claim 11 , wherein the housing and the injector fitting comprise connectors for removably coupling the injector fitting to the housing. 
     
     
         13 . The injector device of  claim 12 , wherein the connectors comprise mating Luer hubs. 
     
     
         14 . The injector cannula of  claim 11 , the hub slidably disposed on the flow cannula such that retracting the hub proximally retracts the tip protector tube. 
     
     
         15 . The injector cannula of  claim 14 , further comprising an elastomeric seal disposed on the hub through which the flow cannula passes with a friction fit around the flow cannula. 
     
     
         16 . The injector cannula of  claim 11 , wherein the hub has a hub interface and the injector fitting has a fitting interface which mates with the hub interface such that the hub interface and the injector interface secure the hub to the injector fitting in the retracted position of the tip protector tube. 
     
     
         17 . The injector cannula of  claim 16 , wherein the hub interface comprises a female tapered surface and the injector fitting interface comprises a male tapered surface. 
     
     
         18 . The injector cannula of  claim 13 , wherein:
 the hub has one or more snaps on the hub, and the injector fitting has a plurality of notches spaced apart longitudinally on the injector fitting, the snaps configured to interface with respective notches of the plurality of notches on the injector fitting to retain the hub and tip protector tube separately in the extended position and the retracted position.   
     
     
         19 . The injector cannula of  claim 11 , wherein:
 the hub and the injector fitting have a sliding interface which rotationally aligns the hub and the fitting and prevents relative rotation of the hub and the injector fitting.