Cellular Binding of Hematoporphyrin Derivative in Human Bladder Cancer Cell Lines: Kk‐47

The fluorescence lifetime and degree of fluorescence polarization of hematoporphyrin derivative (HpD) have been investigated using different solutions: organic and micellar solutions. Ham's F12 medium, and KK‐47 cell suspension. The lifetime and polarization degree in organic and micellar solutions did not change with increasing incubation time, but the polarization degree in the cell suspensions temporarily increased at the initial incubation time and then decreased 4 h after incubation. The lifetime in the cell suspensions exhibited a bi‐phasic exponential decay. The results obtained suggested that mainly dimeric HpD may bind weakly to the cell membrane, and then slowly be distributed throughout the cytoplasm. The polarity and viscosity of the intracellular loci containing HpD were evaluated from the fluorescence polarizations of HpD in MeOH‐H 2 O mixtures and ethylene glycol(EG)‐MeOH mixtures. The dielectric constant and viscosity of the loci containing HpD were 35 and 11 cp, respectively. Accordingly, the intracellular location of HpD were considered relatively hydrophilic loci of the cells.