The antimatter pod jettison system was an emergency system found on board Constitution-class starships that used explosive separator charges to blast the antimatter pods clear of the ship in the event that the ship's magnetic bottle was to rupture. The system could be directly activated from helm station.
This system was nearly utilized in 2269 during Montgomery Scott's attempt to reverse the polarity of the USS Enterprise's fuel flow, after Losira fused the emergency bypass control of the matter-antimatter integrator. (TOS: "That Which Survives")
More advanced warp core jettison systems that operated on similar principles could be found aboard 24th century starships. (Star Trek Generations; Star Trek: First Contact; PRO: "Terror Firma")