Anthracycline Gels. II. Spectroscopic study on doxorubicin--lecithin association products

Thixotropic and thermally reversible gels have been prepared from doxorubicin--lecithin association products (DL12) by addition of salts to their aqueous solutions. The gel formation and the melting profiles have been followed by several spectroscopic techniques (1H NMR, UV-Vis, Circular Dichroism). The transition temperatures increase as the concentration of both the salt and the DL12 is increased, suggesting a progressive closer approach of the gel forming species. The process of the gel formation is cooperative and causes immobilization of the doxorubicin molecules of DL12.