Pure succinic-docetaxel (50 mg) was dissolved in anhydrous dichloromethane in a 50 ml round-bottom flask and activated using EDC (1.2 eq) and NHS (1.2 eq) and triethylammine (TEA) for two hours under nitrogen atmosphere at room temperature. Then, amine-PEG (550 or 1,000 Da, 1 eq) was added into the reaction mixture and left overnight. The so obtained raw product was washed with DCM and dried at low pressure to remove residual Triethylamine (TEA). Then, it was dissolved in a minimal amount of dichloromethane and purified with automatic silica chromatography using a gradient of DCM (Solvent A) and DCM:Methanol (Solvent B, 9:1).