A drug pump drive mechanism (2100, 3100) for use in cooperation with a drug container including a plunger seal and a power and control system, the drive mechanism (2100, 3100) comprising: a drive housing (2130, 3130) including an axis, the housing (2130, 3130) further including at least one window (2131, 3131), a piston (2110, 3110) disposed for movement from at least a retracted first position to an extended second position along the axis, the piston (2110, 3110) being adapted to impart movement to the plunger seal within the drug container, at least one biasing member (2106, 2122, 3106, 3122) disposed and adapted to move from an energized first position to a deenergized second position as a result of the release of energy, the biasing member (2106, 2122, 3106, 3122) being disposed to cause movement of the piston (2110, 3110) from the retracted first position to the extended second position as the biasing member (2106, 2122, 3106, 3122) moves from the energized first position to the deenergized second position, a retainer, the retainer being moveable between a retaining first position and a releasing second position, the retainer being disposed to maintain the biasing member (2106, 2122, 3106, 3122) in the energized first position when the retainer is in the retaining first position, and to release the biasing member (2106, 2122, 3106, 3122) from the first energized position when the retainer moves to the releasing second position, a sleeve assembly (2120, 3120) disposed at least partially within the drive housing (2130, 3130), at least a portion of the sleeve assembly (2120, 3120) being visible through said window (2131, 3131) when the piston (2110, 3110) is one of the retracted first position or the extended second position, and an end-of-dose indicator (2133, 3133), characterised in that at least a portion of the sleeve assembly (2120, 3120) is adapted to move along said axis with the piston (2110, 3110), the sleeve assembly (2120, 3120) not being visible through said window (2131, 3131) when the piston (2110, 3110) is in the other of the retracted first position or the extended second position, and the end-of-dose indicator (2133, 3133) includes at least one switch interconnect (2132, 3132), at least a portion of which is disposed substantially adjacent the window (2131, 3131) and adapted to identify at least one of when the sleeve assembly (2120, 3120) is disposed subjacent the window (2131, 3131) and when the sleeve assembly (2120, 3120) is not disposed subjacent the window (2131, 3131), the switch interconnect (2132, 3132) including a mechanical trigger (2135, 3135) adapted to engage the sleeve assembly (2120, 3120) through the window (2131, 3131), the switch interconnect (2132, 3132) further being adapted to selectively engage the power and control system as a result of the engagement or disengagement end of the trigger (2135, 3135). a drive housing (2130, 3130) including an axis, the housing (2130, 3130) further including at least one window (2131, 3131), a piston (2110, 3110) disposed for movement from at least a retracted first position to an extended second position along the axis, the piston (2110, 3110) being adapted to impart movement to the plunger seal within the drug container, at least one biasing member (2106, 2122, 3106, 3122) disposed and adapted to move from an energized first position to a deenergized second position as a result of the release of energy, the biasing member (2106, 2122, 3106, 3122) being disposed to cause movement of the piston (2110, 3110) from the retracted first position to the extended second position as the biasing member (2106, 2122, 3106, 3122) moves from the energized first position to the deenergized second position, a retainer, the retainer being moveable between a retaining first position and a releasing second position, the retainer being disposed to maintain the biasing member (2106, 2122, 3106, 3122) in the energized first position when the retainer is in the retaining first position, and to release the biasing member (2106, 2122, 3106, 3122) from the first energized position when the retainer moves to the releasing second position, a sleeve assembly (2120, 3120) disposed at least partially within the drive housing (2130, 3130), at least a portion of the sleeve assembly (2120, 3120) being visible through said window (2131, 3131) when the piston (2110, 3110) is one of the retracted first position or the extended second position, and an end-of-dose indicator (2133, 3133), characterised in that at least a portion of the sleeve assembly (2120, 3120) is adapted to move along said axis with the piston (2110, 3110), the sleeve assembly (2120, 3120) not being visible through said window (2131, 3131) when the piston (2110, 3110) is in the other of the retracted first position or the extended second position, and the end-of-dose indicator (2133, 3133) includes at least one switch interconnect (2132, 3132), at least a portion of which is disposed substantially adjacent the window (2131, 3131) and adapted to identify at least one of when the sleeve assembly (2120, 3120) is disposed subjacent the window (2131, 3131) and when the sleeve assembly (2120, 3120) is not disposed subjacent the window (2131, 3131), the switch interconnect (2132, 3132) including a mechanical trigger (2135, 3135) adapted to engage the sleeve assembly (2120, 3120) through the window (2131, 3131), the switch interconnect (2132, 3132) further being adapted to selectively engage the power and control system as a result of the engagement or disengagement end of the trigger (2135, 3135).