Simple and convenient method for estimation of marker entrapped in liposomes

We have developed a new method to determine the marker calcein encapsulated in liposomes using ethanol or propanol instead of Triton X-100. Calcein in ethanol solution was estimated by fluorophotometry with excitation and emission wavelengths of 490 nm and 520 nm, respectively. The fluorescence intensity of calcein solubilized by ethanol was linear in the range of 10(-6)-10(-4) mol/L with a correlation coefficient of 0.999. The proposed method, which was accurate and reproducible, was successfully applied to determine the amounts of ethanol-soluble drugs in liposomes.