Ultrasound liberates nitric oxide (NO) from the caged NO compound N,N′-bis(carboxymethyl)-N,N′-dinitroso-p-phenylenediamine sodium salt

To determine whether nitric oxide (NO) can be released from a cage compound N,N′-bis(carboxymethyl)-N,N′-dinitroso-p-phenylenediamine sodium salt (BNN 5 Na), we sonicated different concentrations of BNN 5 Na solutions containing an NO spin trap, (MGD)2Fe2+, and then measured (MGD)2Fe2+–NO signal using electron paramagnetic resonance (EPR). We also investigated the role of cavitation by saturating the solutions with Ar, He or Xe gases before sonication. The result showed that ultrasound can liberate NO from caged NO compound at rates highest with Xe and lowest with He. These results suggest that high-temperature due to cavitations induced by ultrasound are capable of releasing NO from caged NO compounds. This finding also opens up to a new possibility for the use of ultrasound in a controlled release of active compound (e.g. drug) from its caged form for therapeutic purposes.