Determining sodium azide concentration in blood by ion chromatography.

We describe a simple method for measuring sodium azide concentrations in aliquots of blood and other tissues. Aliquots are acidified, converting azide to volatile hydrazoic acid (HN3) which is then trapped in sodium hydroxide. We analyze the resulting aliquots by ion chromatography, using a sodium tetraborate eluent and suppressed conductivity detection.

Bioactivation of nitroprusside by porcine endothelial cells.

Sodium nitroprusside (Na2[(CN)5FeNO], SNP), which is stable, diamagnetic, and not detectable by electron paramagnetic resonance (EPR) spectroscopy, can be activated by one-electron reduction. The initial product, which retains the five cyanides and is here called penta, has a distinctive EPR signal. Penta spontaneously dissociates the trans-cyanide ligand resulting in a second paramagnetic species called tetra, which has a different and distinctive EPR signal.

An impurity present in some samples of SIN-1 oxidizes it to nitric oxide in anaerobic solutions.

N-Morpholino-N-nitrosoaminoacetonitrile (SIN-1), a nitrovasodilator metabolite of the drug, molsidomine, is widely used in studies on the pharmacology and toxicology of nitric oxide (NO) because solutions of SIN-1 'spontaneously' release NO in a pathway involving molecular oxygen. Preliminary results, however, suggested that SIN-1 could react with hemoglobin in anaerobic solutions to release NO and form NO-hemoglobin. Electron paramagnetic resonance (EPR) studies showed that heme(III) of methemoglobin was not being reduced, thereby not serving as the oxidant in the reaction generating NO-hemoglobin.

Effects of temperature, oxygen, heme ligands and sulfhydryl alkylation on the reactions of nitroprusside and nitroglycerin with hemoglobin.

Nitrovasodilators react with hemoglobin (Hb) to form heme(III) and nitric oxide (NO)Hb. These reactions can be exploited as models for events that take place at the cellular level leading to the biological effects of the prodrugs. Sodium nitroprusside (SNP) is known to undergo a one-electron reduction in its reaction with heme(II), resulting in the labilization of the cyanide ligand trans to the NO ligand.