Dimers of polyene antibiotic amphotericin B detected by means of fluorescence spectroscopy: molecular organization in solution and in lipid membranes

Molecular organization of antifungal antibiotic amphotericin B in lipid monolayers studied by means of Fluorescence Lifetime Imaging Microscopy

“…6). As can be seen, the dimer association energy determined in the present work on the basis of the fluorescence lifetime measurements, 5.9 kJ/mol, is very close to the one reported previously [15].…”

“…According to our earlier report [15], confirmed recently by Stoodley et al [18], AmB displays measurable fluoresce which can be analyzed, providing that fluorescing contaminations are separated [19]. Despite relatively low quantum yield fluorescence can be applied to distinguish different organization forms of molecules of the drug in different environments (even in not transparent natural samples).…”

“…2 presents the electronic absorption spectrum of AmB dissolved in water medium alkalized to pH 12, in order to assure monomeric organization of the drug [21]. The main absorption band, with the 0-0 vibrational maximum at 405 nm, corresponds to the electronic transition from the ground energy level (1 1 A g ) to the so-called S 2 energy level (1 1 B u ) [15,21].…”

“…2). In particular, the short wavelength spectral components represent the high energy excitonic states characteristic of the dimeric and also more complex in solution of AmB in 40% 2-propanol at different temperatures were analyzed in terms of the van't Hoff equation [15] (Fig. 6).…”

“…one oriented parallel and the other one perpendicular with respect to the plane of the membrane [13][14][15]. It appeared that a laterally-oriented pool was particularly large in the membranes containing ergosterol and that such orientation of the drug had strongest effect on the membrane organization [13].…”