A perfusion catheter system that allows selective temporary perfusion of small vascular or other anatomic structures arising from a host structure atraumatically. The active ingredient is sealed away from excipients that can adversely affect stability by sealing the excipients rather than the active ingredient. The clamp has an engaging section for engaging the clamp engaging member, a fixing section fixed on the bottom cowl by the clamp fixing member, a mounting pivot formed on the fixing section, and a supporting pivot linked to the mounting pivot.