A system and method for dispensing a nitric oxide solution, and more preferably a gas/liquid mixture of nitric oxide in a solvent, from a cylinder or other containment vessel are provided. The dispensing system and method are configured so as to maintain the nitric oxide based solution within the cylinder or containment vessel at a constant pressure above ambient pressure as the gas/liquid mixture is stored in and depleted from the containment vessel thus preventing the nitric oxide from coming out of the solution. In addition, a method of producing the gas/liquid mixture of nitric oxide in a solvent, such as deoxygenated and deionized water, as well as a cylinder filling method and apparatus are also provided.
