A pentablock copolymer of Poly(Lactide-co-Glycolide) and Pluronic F68 was synthesized using ring-opening polymerization and characterized by NMR and FTIR for confirming the structure of the block copolymer. TG-DTA studies showed PLGA:Pluronic ratio to be 4:1. As the PLGA-PEO-PPO-PEO-PLGA Pentablock Copolymer (PPPC) prepared is amphiphilic, its Critical Vesicular Concentration, was measured, which was lower at 37 °C than at 25 °C, which could provide better stability to the system at physiological temperature. The nanoparticles of PPPC vary in topographyand range from 150 to 500 nm in size, according to the synthesis route used viz Emulsion Solvent Evaporation and simple dialysis. Pentablock copolymer nanoparticles were found to entrap about 84% of hydrophobic drug, docetaxel. Drug release profile of docetaxel showed about 50% release in first 2 hours at pH 4.6 and about 80% docetaxel was released at pH 7.4, at the end of 2 days. The PPPC nanoparticles was found to be biocompatible to L929 cell lines up to 1 mg/ml concentration. Preliminary in vitro cytotoxic effect of docetaxel loaded PPPC nanoparticles against four different cancer cell lines showed 50% inhibitory concentration of 6 nM in A431 (Squamous cell carcinoma), 250 nM in HeLa (Cervical carcinoma), 800 nM in PC3 (Prostate carcinoma) and 1 μM in KB (Epidermoid carcinoma) cells. Copyright © 2014 American Scientific Publishers.