Cisplatin-incorporated nanoparticles of methoxy poly(ethylene glycol)-b-poly(L-glutamic acid) copolymer

We fabricated cisplatin-incorporated nanoparticles using block copolymer composed of methoxy poly(ethylene glycol) (MPEG) and poly(L-glutamic acid) (PGA) (abbreviated as GE). For synthesis of block copolymer, MPEG was directly conjugated to the terminal amine of PGA. Cisplatin-incorporated nanoparticles was prepared by ion complex formation of cisplatin and PGA domain of block copolymer. Size of cisplatin-incorporated nanoparticles was less than 200 nm at particle size measurement and their shapes were spherical at TEM observation. To study drug release properties, cispaltin release from nanoparticles were performed at phosphate-buffered saline (PBS, 0.01 M, pH 7.4) and distilled water, indicating that cisplatin release rate at PBS was approximately three times higher than that of deionized water. The cell growth inhibition of cisplatin incorporated nanoparticles in vitro was tested with HuCC-T1 cells. Cisplatin-incorporated nanoparticles were effectively inhibited tumor cell growth as similar as cisplatin itself. In other words, nanoparticles showed decreased inherent cytotoxicity compared to cisplatin against normal cells. We suggest that cisplatin incorporated GE nanoparticles is a good candidate for antitumor drug targeting.