Distribution coefficient of rifabutin in liposome/water system as measured by different methods

Distribution coefficient (D) of rifabutin in liposome/water system was measured by phase separation and fluorescence probe quenching techniques. D values were identical suggesting that rifabutin is fully immersed into lipid bilayer. Structural studies of phospholipid bilayer employing 31P NMR spectroscopy demonstrated that introduction of rifabutin does not alter the bilayer structure. A scheme of the rifabutin position in lipid bilayer based on the calculated size of rifabutin molecule is proposed.