Lidocaine Hydrochloride Injection, USP is a sterile, nonpyrogenic solution of an antriarrhythmic agent administered interavenously by either direct injection or continuous infusion. It is available in the following concentration: 5mL (100 mg), 6.0 (5.0 to 7.0) pH. May contain sodium hydroxide and/or hydrocholoric acid for pH adjustment. Injections containing 10 mg/mL (1%) contain sodium chloride 7 mg and injections containing 20 mg/mL (2%) lidocaine hydrochloride contain sodium chloride 6 mg to adjust tonicity. Single dose solutions contain no preservative and unused portions must be discarded after use. Lidocaine Hydrochloride, USP is a white powder freely soluable in water. The molecular weight is 288.82. The plastic syringe is molded from a specially formulated polypropylene. Water permeates from inside the container at an extremely slow rate which will have an insignificant effect on solution concentration over the expected shelf life. Solutions in contact with the plastic container may leach out certain chemical components from the plastic in very small amounts; however, biological testing was supportive of the safety of the syringe material.