Hazardous agent injection system

1. A hazardous agent injection system, the hazardous agent injection system comprising:

methotrexate in an amount of from about 0.02 ml to about 4.0 ml and at a concentration of from about 7.5 mg/ml to about 150 mg/ml in a pharmaceutically acceptable solvent;

a powered injector, the powered injector comprising:

a prefilled syringe, comprising a container including a pharmaceutical solution formulation of the methotrexate and a pharmaceutically acceptable solvent;

an injection-assisting needle configured to pierce the skin of a patient and deliver methotrexate to the patient subcutaneously;

a firing mechanism associated with the prefilled syringe and configured to expel the methotrexate from the prefilled syringe through the needle for injecting the methotrexate;

an energy source associated with the firing mechanism and configured to power the firing mechanism and to inject the methotrexate from the injection outlet member; and

a trigger mechanism associated with the firing mechanism and configured to activate the firing mechanism,

wherein the powered injector is configured to subcutaneously inject the methotrexate from the prefilled syringe in less than 5 seconds, such that one or more of confidence intervals of (a) the maximum concentration of methotrexate in blood plasma of a patient following administration of a dose of the methotrexate to the patient (“C max ”) with the hazardous agent injection system, (b) the time to reach the maximum concentration of methotrexate in blood plasma of a patient following administration of a dose of the methotrexate to the patient with the hazardous agent injection system (“T max ”) and (c) area under the curve of the concentration of methotrexate in blood plasma of a patient following administration of a dose of the methotrexate to the patient with the hazardous agent injection system of the injected methotrexate (“AUC”) falls between about 80% and about 125% of a measured confidence interval of the same dose of methotrexate delivered by a hand-powered syringe.

2. The hazardous agent injection system of claim 1 , wherein the gauge of the injection-assisting needle is selected from 26 gauge and a higher gauge number.

3. The hazardous agent injection system of claim 1 , wherein the powered injector is configured to inject the methotrexate such that the methotrexate is injected at a flow rate of at least about 0.5 ml/sec.

4. The hazardous agent injection system of claim 1 , wherein the energy source comprises a spring.

5. The hazardous agent injection system of claim 1 , wherein the energy source is configured for generating a pressure of at least about 80 p.s.i. in the container.

6. The hazardous agent injection system of claim 1 , wherein the powered injector further comprises an outer housing member configured for allowing a user to handle the injector.

7. The hazardous agent injection system of claim 6 , the powered injector further comprises a safety member removably affixed to the outer housing.

8. The hazardous agent injection system of claim 6 , wherein the powered injector is a jet injector.

9. The hazardous agent injection system of claim 6 , wherein the powered injector is not a jet injector.

10. The hazardous agent injection system of claim 7 , wherein the safety member is removably affixed to the distal end of the outer housing.

11. The hazardous agent injection system of claim 7 , wherein the safety member is removably affixed to the proximal end of the outer housing.

12. The hazardous agent injection system of claim 7 , wherein the powered injector is a jet injector.

13. The hazardous agent injection system of claim 7 , wherein the powered injector is not a jet injector.

14. The hazardous agent injection system of claim 10 , wherein the safety member is a cap.

15. The hazardous agent injection system of claim 11 , wherein the safety member is removably affixed to the proximal end of the outer housing by a plurality of tabs that extend through matching openings formed in the outer housing to form a press-fit between the safety member and the outer housing.

16. The hazardous agent injection system of claim 1 , wherein the injector further comprises a syringe sleeve, the syringe sleeve having bore portion configured to abut the outside of the prefilled syringe wall so as to minimize syringe movement resulting from of the firing mechanism action.

17. The hazardous agent injection system of claim 1 , wherein the injection-assisting needle is associated with the prefilled syringe.

18. The hazardous agent injection system of claim 1 , wherein the injection-assisting needle is associated with the powered injector.

19. A method of treating a patient having an autoimmune disease, the method comprising administering methotrexate to the patient using the hazardous agent injection system of claim 1 .

20. The method of claim 19 , wherein the autoimmune disease is selected from the group consisting of rheumatoid arthritis, juvenile rheumatoid arthritis, psoriatic arthritis, systemic lupus erythematosus, steroid-resistant polymyositis or dermatomyositis, Wegener's granulomatosis, polyarteritis nodosa, and vasculitis.