The physicochemical properties of a novel amphiphilic polymer–paclitaxel conjugate monomethoxy-poly(ethylene glycol)-b-poly(lactide) (MPEG-PLA) and a cyclic small peptide c(RADfK)-paclitaxel containing the arginyl-glycyl-aspartic acid (RGD) amino acid sequence have been evaluated using Density Functional Theory (DFT) and Hartree Fock (HF) calculations. In the both complexes the linking positions are 2'- and 7-OH groups of taxol. Our investigation include: geometrical parameters of paclitaxel complexs, Gibbs free energy of solvation (
Gsolvation), binding energy (BE) and Dipole Moment (DM) of prodrugs, beside some other properties such as partition coefficient, polarizibility, hydration energy and etc. Our results indicate that these carrier-paclitaxel complexes mentioned above can be used to improve anti cancer activity and water-solubility of paclitaxel.