Wenk MR Fahr A Reszka R Seelig J 1996 Paclitaxel (taxol) is diterpenoid anticancer drug with a new mechanism of cytostatic action. It is under investigation in clinical trials for treatment of various types of human cancer. A major difficulty in developing paclitaxel as a chemotherapeutic agent in its poor water solubility. In order to improve the bioavailability of paclitaxel, novel vehicle systems such as mixed micelles or liposome-based formulations are being developed. In this study we determined the partition coefficient of paclitaxel partitioning into small unilamellar lipid vesicles composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine using two different methods, namely high-sensitivity titration calorimetry and fluorescence spectrometry. We measured a partition coefficient of Kp approximately equal to 9,500 M-1, a partition enthalpy of Delta H = -25 +/- 3 kcal mol-1 and a free energy of binding of Delta G = -7.9 kcal mol-1. The binding reaction is enthalpy-driven, which can be explained by van der Waals interactions between the hydrophobic drug and the strong temperature dependence of the partition equilibrium. A temperature increase of 10 degrees C reduces the paclitaxel solubility in the lipid phase by a factor of 4. https://sonar.ch/global/documents/129370 eng info:eu-repo/semantics/altIdentifier/doi/10.1021/js950120i info:eu-repo/semantics/altIdentifier/pmid/8683453 Journal of pharmaceutical sciences. - 1996 Lipid Bilayers Paclitaxel Temperature Time Factors Paclitaxel partitioning into lipid bilayers. http://purl.org/coar/resource_type/c_6501