A delivery device for delivering material into a catheter through a catheter port includes a cannula having a generally tubular shape and a distal end and a stability collet having a distal attachment portion configured to attach the stability collet to a catheter port. The stability collet has a longitudinal channel through which the cannula extends. The longitudinal channel is dimensioned to allow a longitudinal movement of the cannula in the longitudinal channel. The delivery device further includes an elastic member acting between the cannula and the stability collet. The elastic member biases the cannula distally relative to the stability collet. Thus, when the stability collet is attached to the catheter port, the cannula is urged toward the catheter port, thus reducing a risk of improper alignment between the cannula and the catheter port.
