Kinetics of hemolysis induced by thioridazine

Abstract

The process of hemolysis of erythrocyte suspension induced by thioridazine (TDZ) was investigated by measuring the UV-Vis absorbance spectrum in the range 200 nm - 700 nm. The time needed to obtain the spectrum in this range was 12.5 s, so the spectrum was measured each 15 s. This permitted to follow the changes in absorbance at different wavelengths of the spectra during hemolysis. It was found that at most of the wavelengths measured the absorbance decreased which was related to the decrease of the light-scattering by the intact erythrocytes. In contrast, the absorbance peak of the hemoglobin (Hb) at 416 nm increased significantly during hemolysis. This was attributed to smaller light absorption by Hb when the erythrocytes were still intact and the Hb is still inside the erythrocytes. This phenomenon was due to the forward-scattered light that did not penetrate the erythrocytes and did not interact with Hb. When Hb was released from erythrocytes it could already interact with the light, resulting in increase of the absorption peaks of Hb and especially of the peak at 416 nm. The kinetics of the decrease of light-scattering at 700 nm and 500 nm and the increase of Hb absorption at 416 nm were compared and it was found that they are directly related. The kinetics of hemolysis induced by different concentrations of TDZ were measured. It was found that the time for hemolysis depended on the TDZ concentration as power function with power factor of minus 5.