Unexpected effect of Tris buffer on photophysical properties of Fluoroquinolone Antibiotics

HUGO A. PÉREZ Y FAUSTINO E. MORÁN VIEYRA

Santiago del Estero

Congreso; XLIV Reunión Anual Sociedad Argentina de Biofísica (SAB); 2015

Laboratory of Biointerphase and Biomimetic Systems

Fluoroquinolones(FQs) are broad-spectrum antibiotics that have been used to treat variousinfections since the 1980s [1] .However, these drugs can cause side effects,including phototoxicity and photocarcinogenicity photomutagenicity [2]. To ourknowledge, there are few studies on the effect of buffer2-amino-2-hydroxymethyl-propane-1,3-diol (Tris) in the photophysical propertiesof FQs photophysical In this work the effect of Tris buffer was studied withfluoroquinolones ciprofloxacin (Cpx), norfloxacin (Nor), levofloxacin (Lev),using techniques of absorption and emission of steady state and dynamic (LFPand TCSPC). It is observed the presence of Tris buffer decreases thefluorescence intensity of FQs, but not lifetimes, demonstrating that themechanism of deactivation is purely static. Obtaining values ​​of KSV≅ 0.6 M-1. Constantdeactivation of triplet states FQs Tris (kQT ≅ 2.6 x 106M-1s-1)is less than the value diffusional water (≅109M-1s-1).This can be explained because the FQs are as zwitterionic and positivelycharged Tris pH = 7.4, generating a repulsion effect between species.