Mouse liver microsomes (MLM) protect erythrocytes against trifluoperazine (TFP) induced and mechanical hemolysis which are due to TFP microsomal transformation and to the action of an unidentified water-soluble microsomal factor (UF).

Trifluoperazine (TFP), a phenothiazine derivative, produces either hemolysis or protection of erythrocytes under isosmotic conditions in a dose-dependent manner. The hemolytic effect of TFP is abolished in the presence of mouse liver microsomes (MLM) which is due, in part, to drug incorporation, transformation and a MLM enzyme driven metabolism. An unidentified water-soluble factor (or factors) derived from MLM has been found to protect erythrocytes against both mechanical and TFP-induced isosmotic hemolysis.