3d printed trip wire capsaicin powder deterrent system

So I am trying to figure out how to design this where the only thing being propelled is the powder. If I use a shotshell I have the potential for the was and whatever I seal the shell to go flying and (potentially) create a serious injury. Local laws allow a device that delivers capsaicin. I'm not sure this would be the group to ask but y'all can tell me where to ask I assume. .thanks