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[Ionization of the acid-base groups of polyene antibiotics in aqueous solutions].

Authors
Type
Published Article
Journal
Antibiotiki
Publication Date
Volume
20
Issue
8
Pages
678–681
Identifiers
PMID: 7187
Source
Medline
License
Unknown

Abstract

The acid-base characteristics of polyenic antibiotics, such as nystatin, mycoheptin and levorin in aqueous solutions were studied. A special procedure provided the use of potentiometric titration for investigation of ionization of the groups of vater-insoluble substances. The ionization constants of the carboxylic and amine groups of the antibiotics at several temperatures were determined. It was found that ionization of the acid group did not practically depend on the temperature. At the same time the heat effect of the amine group ionization was significant and amounted to about 10 kcal/mole. Thermodynamic analysis of the ionization process of the polyenic antibiotics in aqueous solutions was performed. Integral components defining the process energetics were calculated.

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