Auto injector and injection spring for aged prefilled syringe

A method of adapting an auto injector configured to actuate a prefilled syringe, the auto injector having a biasing member having a spring constant, the prefilled syringe being filled with a volume of therapeutic fluid, the prefilled syringe including a barrel, stopper, and a needle, the stopper having a path of travel, the biasing member arranged to move the stopper along the path of travel. An auto injector having an injection spring adapted to an aged prefilled syringe. 一种调适被构造成致动预填充针筒的自动注射器的方法，该自动注射器具有偏压构件，该偏压构件具有弹簧常数，该预填充针筒填充有一定体积的治疗用流体，该预填充针筒包括筒体、止挡件、和针头，该止挡件具有行进路径，该偏压构件被布置为使止挡件沿着行进路径移动。一种具有适用于老化的预填充针筒的注射弹簧的自动注射器。