A catheter having a drug delivery unit at the distal end thereof. The drug delivery unit includes an actuator capable of assuming an activated and an inactivated configuration. The drug delivery unit also includes a receptacle capable of accepting a therapeutic agent. The actuator and receptacle are in communication with each other such that the actuator transmits force to the receptacle and the receptacle accepts force from the actuator in an activated configuration of the actuator. Also provided is a method of delivering a therapeutic agent to a target site using the catheter of the present invention.