pH-Sensitive Paramagnetic Probe 4-(Methylamino)-2-Ethyl-5,5-Dimethyl-4-Pyridine-2-Yl-2,5-Dihydro-1H-Imidazol-1-Oxyl for Controlling Microacidity Inside Poly-D,L-Lactide Films during Degradation In Vitroстатья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 20 августа 2024 г.
Аннотация:Monitoring of the acidity inside the pores of aliphatic polyesters during their swelling and hydrolysis is important challenge of biomedicine. pH-sensitive nitroxyl radical 5,5-dimetyl- 4-dimetylamino-2-ethyl-2-(4-pyridyl)-2,5-dyhydroimidazole-1-oxyl (DPI) was used to control the acidity inside thin film of poly-D,L-lactide. Based on the analysis of DPI EPR spectra, it was found that the pH in liquid-filled pores formed in the polymer matrix does not exceed 2 from the very beginning. Possibly, the generation of the pores proceeds due to the catalysis of polylactide hydrolysis by terminal carboxyl groups of the polymer or by basic groups of the nitroxide probe. A sharp increase in the number of the motile paramagnetic particles is observed in the first two days which is consistent with the formation of liquid-filled pores. Within 7–9 days, the amount of motile probes in the pores accumulates, and then begins to decrease over time. In parallel, theamount of the immobilized nitroxides becomes negligible in 10–15 days. The release rate of DPI from the poly-D,L-lactide film is independent of time, which is preferable when similar systems are used as controlled drug release units.