A single-use syringe assembly is disclosed which includes a syringe body defining a fluid reservoir and including an engagement surface, a plunger assembly including a plunger rod and a sealing member supported on a distal end of the plunger rod, and a releasable member having a proximal end releasably positioned within a sealing member throughbore and a distal end configured to engage the engagement surface of the syringe body when the sealing member is moved to the advanced position. The proximal end of the releasable member being configured to seal the sealing member throughbore. The releasable member is configured such that a force required to remove the distal end of the releasable member from engagement with the engagement surface of the syringe body is greater than the force required to disengage the proximal end of the releasable member from the sealing member throughbore. As such, upon movement of the sealing member from the advanced position to the retracted position, the proximal end of the releasable member is disengaged from the sealing member throughbore to unseal the throughbore.