A system (10, 200) and corresponding method for introducing a drug delivery device (18, 218) through at least part of a biological barrier starts with the drug delivery device (18, 218) deployed within a channel of a hollow needle (12, 212). The hollow needle is inserted into the biological barrier and the drug delivery device is pushed forward by a suitable plunger. The drug delivery device is preferably anchored to the biological barrier through a radially expanding retention arrangement (36, 36&prime；, 36a), and is preferably filled with a liquid drug after deployment via a filling needle (24, 222) extending within the channel of the hollow needle (12, 212).
