SmartTranq

"SmartTranq" was a type of synthetic tranquilizer produced by the company Field Sports, in cooperation with the Corellian Chemical Corporation, for use in their air rifle, the Model 77 air rifle. The chemical contained an active ingredient, which when introduced to a targets bloodstream began to mutate and adapt constantly, ensuring optimal effectiveness in overcoming their immune system and rendering them unconscious whatever their species. The tranquiliser could be added to the dart ammunition of the Model 77 for 500 undefined.

Behind the scenes
The LBR-9 was first mentioned in Enter the Unknown, a sourcebook written by Sterling Hershey and released in 2013 for Fantasy Flight Games' Star Wars: Edge of the Empire roleplaying game.