An injection device comprising a high-viscosity fluid in an inner compartment thereof for delivering the high-viscosity fluid to a patient, comprising: a barrel having an interior space formed by a sidewall for containing at least a high-viscosity fluid to be dispensed by the injection device, a plunger end, and an open end , the open end including a front wall and a nozzle having a constriction point and an orifice , the front wall extending from the constriction point to the orifice ; wherein the interior space of the barrel includes an inner concentric wall positioned within the sidewall, wherein the inner concentric wall defines the inner compartment having the high-viscosity fluid comprising a protein having an absolute viscosity of from 5 centipoise (5 mPa·s) to 1000 centipoise (1000 mPa·s ) and an outer compartment having a low- viscosity fluid within the barrel, and wherein the inner concentric wall has one or more openings formed between the inner concentric wall and the front wall permitting fluid communication between the compartments; a plunger movably operable within at least one compartment of the barrel; wherein the plunger is adapted to provide a depressing force substantially concurrently to the high-viscosity fluid within the inner compartment and the low-viscosity fluid within the outer compartment, thereby producing an annulus of the low-viscosity fluid around a core of the high-viscosity fluid as the fluids are dispensed from the orifice, and wherein the injection device is a manual syringe or auto-injector, characterised in that prior to the injection device being used, the nozzle is filled with only the low-viscosity fluid. a barrel having an interior space formed by a sidewall for containing at least a high-viscosity fluid to be dispensed by the injection device, a plunger end, and an open end , the open end including a front wall and a nozzle having a constriction point and an orifice , the front wall extending from the constriction point to the orifice ; wherein the interior space of the barrel includes an inner concentric wall positioned within the sidewall, wherein the inner concentric wall defines the inner compartment having the high-viscosity fluid comprising a protein having an absolute viscosity of from 5 centipoise (5 mPa·s) to 1000 centipoise (1000 mPa·s ) and an outer compartment having a low- viscosity fluid within the barrel, and wherein the inner concentric wall has one or more openings formed between the inner concentric wall and the front wall permitting fluid communication between the compartments; a plunger movably operable within at least one compartment of the barrel; wherein the plunger is adapted to provide a depressing force substantially concurrently to the high-viscosity fluid within the inner compartment and the low-viscosity fluid within the outer compartment, thereby producing an annulus of the low-viscosity fluid around a core of the high-viscosity fluid as the fluids are dispensed from the orifice, and wherein the injection device is a manual syringe or auto-injector, characterised in that prior to the injection device being used, the nozzle is filled with only the low-viscosity fluid. <EOS>