Rifabutin solubility within pH 3.0 to 11.0 was determined. Potentiometry, spectrophotometry and computation revealed ionization of three groups with pKa 3.5, 6.5 and 9.5 in the rifabutin molecule. On the basis of the pKa values of certain fragments of the rifabutin molecule computed by the ACD/pKa programme they were related to ionization of the following groups: imidazole residue nitrogen, aromatic hydoxyl and piperidin nitrogen respectively. Interaction of rifabutin with model membranes, i. e. large unilamellar vesicules was studied. At lower pH of the medium, entrapment of rifabutin to the large unilamellar vesicules increased that was evident of satisfactory correlation with the decrease in the rifabutin distribution coefficient in the system multilamellar vesicules/water under the experimental conditions.
|Original language||English (US)|
|Number of pages||5|
|Journal||Antibiotiki i Khimioterapiya|
|State||Published - Dec 1 2005|
- Distribution coefficient
- Ionization constants
- Large unilamellar vesicules