The invention relates to an injection catheter for delivering a therapeutic agent into a substrate, comprising one or more lumens and a curved delivery element, said lumen serving as a guide for said curved delivery element outside of the substrate； said curved delivery element comprising openings on its distal tip, said distal tip comprising a distal zone and a proximal zone, said injection catheter being characterized in that the specific surface in said distal zone of said distal tip of said curved delivery element is higher than the specific surface in said proximal zone of said distal tip of said curved delivery element. The invention also relates to a process for delivering a therapeutic agent into a substrate.
