Do shape transformations in erythrocytes reflect the flip rate of amphiphilic compounds?

It has been shown that the time course of echinocyte to discocyte transformation caused by exogenous phospholipids is an accurate measure of the flip rate of the phospholipids in the lipid bilayer [1,2]. In order to explore whether shape changes in erythrocytes are indicative of flip rates of water- soluble amphiphiles, the time course of shape changes caused by a large number of amphiphiles was studied. In case of amphiphiles inducing echinocyte to discocyte or discocyte to stomatocyte transformation it is proposed that the time course of shape transformation may be indicative of the flip rate of the amphiphiles. The relevance of using shape changes in erythrocytes as a tool to estimate flip rates of amphiphiles is discussed.