Auto-injector with anti-roll features

The present disclosure relates to a therapeutic agent delivery device with anti-roll features. In one embodiment, a therapeutic agent delivery device may include a tubular body including a first end portion, a second end portion, and a lumen extending between the first end portion and the second portion. An outer surface of the tubular body includes a first opening in communication with the lumen. The outer surface of the tubular body further may include a ledge extending around a periphery of the first opening, and a portion of the ledge closest to the second end portion of the tubular body may be shaped as an arrowhead. The therapeutic agent delivery device also may include a cap configured to engage the second end portion of the tubular body, wherein the cap may include a central longitudinal axis, a first end having a first cross-sectional dimension, and a second end having a second cross-sectional dimension larger than the first cross-sectional dimension. The cap may further include a curved sidewall extending radially outward from the first end to the second end, and the curved sidewall may include a protrusion.