Fluorescence anisotropy of membrane fluidity probes in human erythrocytes incubated with anthracyclines and glutaraldehyde

We have demonstrated that out of tested drugs, idarubicin (IDA) and daunorubicin (DNR), only DNR caused statistically significant alterations in membrane fluidity. The changes were noted mainly in the hydrophobic regions of the lipid bilayer tested with 12-AS and DPH probes. However, when DNR or IDA preincubated cells were treated with glutaraldehyde, alterations in the plasma membrane fluidity were observed in the polar as well as in the deeper regions of the lipid bilayer. Because changes observed for TMA-DPH were the biggest from among tested probes we speculate that glutaraldehyde immobilizes drugs mainly at the surface of the erythrocytes cell membrane.