Patent ID: 9192732
Filing Date: 2015-11-24
Classification: A61M

Abstract:
1. A syringe having a retractable needle, the syringe comprising: a syringe barrel; a needle disposed at a distal end of the syringe barrel, the needle having a needle header at its proximal end; a plunger slideable within the syringe barrel for injecting medicament and having a retraction lumen for receiving the needle when the needle is retracted; a needle carrier sealingly engaged within a distal end of the plunger, the needle carrier having a distal bearing surface against which gas under pressure may bear and being initially retained in a fixed position relative to the plunger, the needle carrier being slideable within the retraction lumen in response to force applied by gas under pressure; a gas release cell located within the syringe barrel distally of the needle carrier; and gas release trigger means located within the syringe barrel distally of the needle carrier for rupturing the gas release cell in response to application of a post-injection force to the plunger by a user to release compressed gas in an area confined by the syringe barrel and the needle carrier, wherein the needle carrier is engageable with the needle header to retract the needle into the plunger lumen under force applied by released gas when the gas release cell is ruptured.