Self-diffusion of poly (ethylene oxide) -: modified paclitaxel in dilute aqueous solutions

In order to make the hydrophobic anti-cancer drug Paclitaxel watersoluble, it was coupled to highly uniform poly (ethylene oxide) (PEO) with the molar mass M-w = 5,000 g/mol with a self-immolating succinate linker. The concentration and temperature dependence of the unrestricted molecular mobility of the molecules (long-time self-diffusion) in homogeneous aqueous (D2O) solution was studied by gradient field NMR around body temperature in the highly dilute region. The concentration dependence of the friction coefficient, and the self-diffusion coefficient is unexpectedly strong and probably caused by peculiarities of the shape and/or the flexibility of the molecules rather than their size.