Technical Session - 1

Title:            Thermodynamics of fluoxetine partitioning into lipid membranes
Authors:       Nguyen Thi Xuan Trang, Do Tho Thuy Tien, Pham Hoa Son, Nguyen Thao Trang
Abstract:     The partition coefficients (Kp) of fluoxetine, a well prescribed SSRI antidepressant, between
zwitterionic1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), negative charge 1,2-dipalmitoyl-sn-glycero- 3-phosphoglycerol (DPPG) large unilamellar vesicles (LUVs, 100 nm) and water were determined over a temperature range of 25?-37? using second derivative spectrophotometric method. Fluoxetine was found to partition to a greater extent into the two DPPC and DPPG LUVs with increasing temperature. In addition, the partition coefficient of fluoxetine into DPPG LUVs was higher than into DPPC LUVs, indicating the positively charged drug molecules are highly accessible to the negatively charged DPPG bilayers. Van’t Hoff analysis of the temperature dependence of Kp value revealed positive values for both ?H and ?S, suggesting an entropy driven mechanism for fluoxetine partitioning into DPPC and DPPG LUVs. An in-depth study of the thermodynamic characterization of fluoxetine partitioning can shed light onto understanding the energetic forces driving the drug molecules to interact with lipid membranes.

Keywords:  Fluoxetine, Large Unilamellar Vesicles, Thermodynamics, Partitioning Coefficient,
Second Derivative Spectrophotometry
Pages:       031-038

Download Full Paper