MFAME, N-methyl-N-D-fructosyl amphotericin B methyl ester, a new amphotericin B derivative of low toxicity: relationship between self-association and effects on red blood cells.
In aqueous solutions N-methyl-N-D-fructosyl amphotericin B methyl ester (MFAME), a novel amphotericin B derivative with low animal toxicity, similar to its parent antibiotic, exists in three forms: monomeric, soluble and insoluble aggregates in equilibrium [1]. The aim of our work was to examine the influence of medium composition on the MFAME self-association and the relationship between MFAME self-association and its toxicity towards red blood cells. The toxicity of MFAME in aggregated state towards red blood cells was tested by measuring the induction of potassium leakage and extent of haemolysis. The proportions of antibiotic species present in various aqueous media were determined by analysis of the UV-Vis spectra as a function of the antibiotic concentration. Numeric decomposition of the spectra allowed identification of four spectral species present in MFAME solutions: monomeric and three aggregated forms. Our results indicate that these aggregates, named type I, type II and type III, are different in terms of spectral properties, as well as effectiveness towards red blood cells. Soluble aggregate types I and III are the active forms of MFAME towards erythrocytes. The medium composition seems to be the main factor determining which type of antibiotic aggregate prevails in solution.
Szlinder-Richert
J
J
Department of Pharmaceutical Technology and Biochemistry, Technical University of Gdansk, Narutowicza St 11/12, 80-925 Gdansk, Poland. szlinder-richert@wp.pl
Mazerski
J
J
Cybulska
B
B
Grzybowska
J
J
Borowski
E
E
D000666:Amphotericin B / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D000935:Antifungal Agents / Q000737:chemistry / Q000494:pharmacology*; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism; D005947:Glucose; D006461:Hemolysis; D006801:Humans; D000432:Methanol; D011188:Potassium / Q000032:analysis; D012965:Sodium Chloride; D012996:Solutions; D013053:Spectrophotometry; D014867:Water
D000935:Antifungal Agents; C108557:N-methyl-N-fructopyranosylamphotericin B methyl ester; D012996:Solutions; D014867:Water; D012965:Sodium Chloride; D000666:Amphotericin B; D005947:Glucose; D011188:Potassium; D000432:Methanol