title: A new method for sustained generation of ultra-pure nitric oxide-containing gas mixtures via controlled UVA-photolysis of nitrite solutions.
abstract: Exogenous gaseous nitric oxide (gNO) is an FDA approved drug for treatment of a variety of human pathologies like Persistent Pulmonary Hypertension in neonates and premature babies, skin lesions and fungal dermatophyte infections. Substantial disadvantages of current gNO-based therapies are the high therapy costs, high storage costs of the gas cylinders, and the rapid contamination of compressed NO gases with various decomposition products. Here we describe a new, very simple, and inexpensive photolytic generator of uncontaminated NO-containing gas mixtures at therapeutic concentrations. The new method bases on UVA-induced and redox-assisted decomposition of nitrite ions in aqueous solutions. NO formation via UVA-induced photolysis of nitrite is accompanied by an OH radical-dependent production of NO(2) that beside its toxic character additionally strongly reduces the NO yield by consuming NO in its reaction to N(2)O(3). During the UVA-induced photodecomposition process both, inhibition of NO(2) formation or NO(2) depletion by antioxidants hinders the NO-consuming reaction with NO(2) and ensured a maximal purity and maximal yield of NO-containing gas mixtures. Therefore, NO-containing gas mixtures generated by the described method are suitable for medical applications like inhalation or gassing of chronic non-healing wounds. Control of temperature, UVA intensity and composition of the reaction mixture allows facile control over the final NO level in the carrier gas over a wide concentration range. We demonstrate the sustained and stable release of NO over a wide dynamic range (10-5000 ppm NO) for many hours. The method avoids contamination-prone long time storage of NO gas. As such, it appears particularly relevant for applications involving the additional presence of oxygen (e.g. inhalation).
authors: Department of Plastic and Reconstructive Surgery, Hand Surgery, and Burn Center, Medical Faculty, RWTH Aachen University, Pauwelsstr. 30, D-52074 Aachen, Germany.
authors: Christian
authors: C
authors: Opländer
authors: Marcel
authors: M
authors: Baschin
authors: Ernst E
authors: EE
authors: van Faassen
authors: Matthias
authors: M
authors: Born
authors: Manfred
authors: M
authors: Möller
authors: Norbert
authors: N
authors: Pallua
authors: Christoph V
authors: CV
authors: Suschek
mesh_terms: D003198:Computer Simulation; D005740:Gases / Q000737:chemistry*; D009569:Nitric Oxide / Q000032:analysis / Q000138:chemical synthesis* / Q000737:chemistry; D009573:Nitrites / Q000737:chemistry*; D010782:Photolysis; D012996:Solutions; D013696:Temperature; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry
chemical_list: D005740:Gases; D009573:Nitrites; D012996:Solutions; D014867:Water; D009569:Nitric Oxide