A critical analysis of microcalorimetric methodology for drug-induced haemolysis

The present work reports a study on the interaction of three drugs, trifluo perazine (TFP), dibucaine (DBC) and praziquantel (PZQ), with erythrocyte me mbranes. Drug-erythrocyte interaction was studied by measuring the drug par tition coefficient between membrane and water, and also by monitoring their haemolytic activity. Microcalorimetric techniques were employed to study d rug-induced haemolysis. TFP presented the highest membrane partition and be st haemolytic efficacy, followed by DEC and PZQ. The heat effects of drug-i nduced haemolysis obtained by using a thermal activity monitor (TAM) were - 18.2 and -3.6 pJ/cell for TFP and DEC, respectively. We were unable to obta in measurable heat effect for PZQ-induced haemolysis. The discrepancy in he at effect values of drug-induced lysis indicates that different pathways ar e involved in haemolysis establishment. Misunderstandings concerning the ef fect of drug-induced haemolysis, found in recent literature, lead us to pre sent a critical analysis concerning microcalorimetric methodology and a com parison between the heat effect values obtained in this work with the value s available in literature. (C) 1999 Elsevier Science B.V. All rights reserv ed.