In vivo evaluation of a microneedle-based miniature syringe for intradermal drug delivery.

A microfabrication process for miniature syringes is described. The MEMS syringes consist of a silicon plate with an array of hollow out-of-plane needles and a flexible poly-dimethylsiloxane (PDMS) reservoir attached to the back of the plate. The PDMS reservoir can be filled with a drug solution or microparticle suspension which is delivered into the skin simply by the pressure of a finger pushing on the miniature syringe. The efficiency of such a syringe for delivering a suspension of microparticles into skin tissue and a radiolabelled protein (albumin) solution into live mice is reported. Such microneedle devices could be used for the intradermal delivery of vaccination agents or for the systemic delivery of highly effective drugs.