Dextrose adduct formation in aqueous teicoplanin solutions

The interaction of Teicoplanin, a glycopeptide antibiotic, with dextrose in aqueous solution has been investigated. The equilibrium concentrations of the adduct formed by the interaction of the dextrose aldehyde and the Teicoplanin amino group is shown to be directly related to the concentration of the dextrose and is thought to be inversely proportional to the hydrogen ion concentration. It was also found that phosphate ion catalyzed the reverse reaction. Approximately 30 days were required to reach equilibrium a 4 degrees C, while equilibrium was established in about 7 days at room temperature. The reaction is reversed with dilution and the rate of the reverse reaction is two to three times faster than expected when phosphate ion is present at 0.05 M. From the temperature dependence of the rate constants, the activation energies for the various reactions were determined to be in the range 67-80 kjoules (16-19 kcal)/mol.