Evaluation of physicochemical properties and bacterial photoinactivation of phenothiazine photosensitizers

VARA, JIMENA; GUALDESI, MARÍA S.; AIASSA, VIRGINIA; ORTIZ, CRISTINA S.

Photochemical and Photobiological Sciences

ROYAL SOC CHEMISTRY

Lugar: CAMBRIDGE; Año: 2019 vol. 18 p. 1576 - 1576

1474-905X

e report herein the physicochemical properties and antimicrobial activity of the new monobrominated derivative Azure B and its parent compound. These dyes are used as photosensitizers for photodynamic therapy and photodynamic antimicrobial chemotherapy.Relevant pharmaceutical properties (pKa, chemical and photochemical stability, and in vitro antimicrobial activity) were determined. A UV-Visible spectrophotometry method was developed and validated according to the International Conference on Harmonization (ICH) guidelines for use in stability indicating studies and determination of the acid dissociation constant of Azure B and its monobrominated derivative. The results showed that both dyes were chemically stable. In addition, the bromination of the phenothiazine dye decreased its photochemical stability and pKa value without affecting the ionization rate at physiological pH.The analytical parameters for validation of the method were: linearity (r2 > 0.9981), limit of detection (LODs)