A transdermal transport device includes a reservoir for holding a formulation of an active principle, and an array of needles which have bores in fluid communication with the reservoir to facilitate transporting the formulation to and from the reservoir through the needles. The device also includes a first actuator which drives the array of needles into the body, and a second actuator which pumps the formulation between the reservoir and the body through the needles. The first actuator is reversible to withdraw the needles from the body.