**Author details**

Toshihide Yamasaki, Fumiya Mito, Yuta Matsuoka, Mayumi Yamato and Ken-ichi Yamada *Faculty of Pharmaceutical Sciences, Kyushu University, Japan* 

### **5. References**


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258 Nitroxides – Theory, Experiment and Applications

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expansion of their use in a wide range of fields.

*Faculty of Pharmaceutical Sciences, Kyushu University, Japan* 

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**4. Conclusions** 

**Author details** 

**5. References** 

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A nitroxide with a long half-life can also be a candidate *in vivo* imaging agent. *In vivo* evaluations have revealed that tetraethyl-nitroxides have several advantages for application as contrast agents for monitoring redox status: non-toxicity, lack of blood pressure-lowering effects, and stability *in vivo*. Recently, it has been reported that the half-life of 4-oxo-2,2,6,6 tetraethyl-piperidine-1-oxyl (TEEPONE) obtained in mice brains is 81.1±0.7 min, indicating that TEEPONE is more stable compared with other nitroxides that are readily converted into hydroxylamines in tissues (Fig. 6) (Emoto et al., 2011). The decay rate of TEEPONE has no relation with ascorbic acid reduction: this compound can effectively scavenge free radicals

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Toshihide Yamasaki, Fumiya Mito, Yuta Matsuoka, Mayumi Yamato and Ken-ichi Yamada

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