STUDY OF THE EFFECT OF ETOPOSIDE ON THE FLUIDITY OF DIPALMITOYLPHOSPHATIDYLCHOLINE LIPOSOME BY DIFFERENTIAL SCANNING CALORIMETRY AND RAMAN SPECTROSCOPY

The interaction of the anticancer drug, etoposide (VP16-213), with DPPC bilayer vesicles was investigated by DSC and Laser Raman techniques. The results present the fact that the incorporation of VP16-213 into aqueous dispersion of DPPC not only shifted the temperatures of phase transition towards higher value but also broadened the half-height width. The Raman spectra of the DPPC liposome in the C—H symmetric strech vibration lost intensity near 2850cm^-1, therefore, it can be predicted that VP16-213 is localized at C₁～C₉ methylene region of the bilayer, which leads to the increase of the membrane's regularity and the decrease of its fluidity.