Determination of properties of Azine derivatives: new promising photosensitizers.

URRUTIA M, ORTIZ C

Rosario

Congreso; Cuarta Reunión Internacional de Ciencias Farmacéuticas (RICiFa 2016); 2016

Determination of properties of Azine derivatives: new promising photosensitizersUrrutia, M.1,2; Ortiz, C.2,3*1 Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA ? CONICET). Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata.2 Departamento de Farmacia, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba.3 Unidad de Investigación y Desarrollo en Tecnología Farmacéutica (UNITEFA ? CONICET).*E-mail: crisar@fcq.unc.edu.arKeywords: monobrominated Neutral Red, Log PHPLC, Chemical stability, Photostability.Photosensitizers (PS) are organic molecules that convert light energy into chemical energy. Neutral Red monobrominated (NRBr) is a new azine PS synthesized in our laboratory derivated from Neutral Red (NR).1The objective of this research was to determine the chemical stability, photostability and octanol-water partition coefficient of the dyes.The chemical stability was evaluated in different buffer solutions at 37ºC by UV-visible spectroscopy and the samples were withdrawn at 1 hour intervals for 32 hours. The photostability was carried out irradiating for 120 minutes (light dose 60.5 J/cm2). The solutions were monitored by UV-visible spectroscopy as a function of time. Parameters such as selectivity, linearity, accuracy, precision, limit of detection and limit of quantitation were determined. Reversed-phase high-performance liquid chromatography (RP-HPLC) was carried out using an Agilent 1100 Series HPLC system and a reversed-phase C18 (Supelco®) column. To determine log PHPLC, methanol-buffer pH 7.4 mixtures were used as mobile phases and seven compounds were evaluated as references.The results obtained for NR and NRBr demonstrated a high chemical stability in the buffer solutions assayed. The NRBr dye in buffer solutions at pH 5.8 and 7.4 was gradually decolorized; however, this effect was almost completely reversed by the addition of HCl to the solutions, indicating an equilibrium between cationic form and nonionic species. On the other hand, the dyes presented high photostability in the evaluated conditions. The log PHPLC obtained for NR and NRBr were (3.2±0.1) and (3.8±0.1), respectively. Lipophilicity for NRBr increased due to electron-withdrawing bromine-substituent, which could lead to a higher cellular uptake which is usually correlated with an increased biological activity.2Based on these results, the Azine dyes exhibited favorable properties; which are important outcomes for Photodynamic Therapy and Antimicrobial Photodynamic Therapy. Therefore, NR and NRBr could be promising PS to be used in photodynamic therapeutic applications.References[1]- M. N. Urrutia, C. S. Ortiz. Spectroscopic characterization and aggregation of azine compounds in different media. Chem Phys. 2013; 412: 41-50.[2]- E. G. Friberg, B. Cunderlíkova, E.O. Pettersen, J. Moan. pH effects on the cellular uptake of four photosensitizing drugs evaluated for use in photodynamic therapy of cancer. Cancer Lett. 2003; 195 (1): 73-80.