Stability of model membranes in the presence of organotin compounds

The influence of tri- and di-alkyltins (TATs and DATs) as well as di- and t riphenyltin compounds (DPhTs and TPhTs) on haemolysis of red blood cells (R BCs) and stability of planar lipid membranes (PLMs) has been studied, The r esults obtained show that the efficiency of TATs (trimethyl-, triethyl-, tr i-n-propyl- and tributyltin chlorides) in destroying PLMs did not differ gr eatly when the compounds were studied in solutions of physiological pH (pho sphate buffer, pH 7.4). A decrease in pH to 5.0 caused small changes in the efficiency of the three largest TAT molecules and a significant decrease i n the efficiency of trimethyltin chloride. Both haemolytic and PLM experime nts showed that the most active TAT was tri-n-propyltin chloride. The destr uctive action of DAT (dimethyl- and dibutyltin) and DPhT dichlorides was so mewhat more differentiated. Dimethyltin dichloride (DMT) interaction with m odel membranes was a little weaker than that of DPhT and dibutyltin dichlor ides and all these compounds influenced the model membranes to a lesser ext ent than TATs or TPhT. To bring about comparable haemolysis effects the dic hlorides had to be used at much greater concentrations than the chlorides. The haemolytic properties of the dichlorides, especially of that of DMT, si gnificantly increased in solution at pH 5.0. TPhT chloride interacted with model membranes similarly to TAT chlorides. Also, no great difference in ef ficiency of this compound was found for the two buffer solutions used, Copy right (C) 2000 John Wiley & Sons, Ltd.