Preparation and Properties of Polyamines: Part II-Controlled and Sustained Release of Nitric Oxide (NO) from Nitrosated Polymers

The secondary amine moieties of polyamines prepared by the reactions of aliphatic diamines, and 1,5-difluoro-2,4-dinitrobenzene, were nitrosated using sodium nitrite and aqueous concentrated sulfuric acid at low temperature. Released NO from these polymers, suspended in water or phosphate buffer solutions (PBS), was measured at increasing time intervals by colorimetric techniques using Griess Reagent. Similar tests were also conducted with model compounds. In general, both the model compounds and the corresponding polymers exhibited similar NO release profiles, with apparent half lives up to 88 h and 81 h, respectively. They were strongly dependent on the length of the alkyl chains derived from the primary amines used for the preparation of these NO-releasing materials. Results from in vitro studies using low molecular weight NO-releasing compounds with PC-12 cell are also reported. High concentration of NO induced neuronal cell death. On the other hand, low concentration of NO inhibited cell death induced by oxidative stress. This suggests that cell survival effect is NO-dependent.