Photoactivation of the nitric oxide donor SIN-1.

This study investigates whether nitric oxide (NO) release from linsidomine (SIN-1), the active metabolite of the antianginal drug molsidomine, is light sensitive. A 9-h irradiation with polychromatic visible light increased the formation of nitrite (NO index metabolite) from SIN-1 (1 mM) by 61% as compared to control samples incubated in the dark. Under the same conditions (9-h irradiation) the concentration of oxygen decreased to 2% of control. However, oxygen consumption was substantially reduced when light was excluded (35% recovery after 9 h). These results show that irradiation with visible light markedly enhances the oxygen-dependent NO release from SIN-1. Thus, sydnonimines appear to be suitable model compounds for the development of photoactivatable NO donors.