Polymer–metal complex nanoparticles-containing cisplatin and amphiphilic block copolymer for anticancer drug delivery

Abstract

Polymer–metal complex nanoparticles-containing cisplatin (cis-dichlorodiammineplatinum(II)), an anticancer drug, was prepared by a ligand-exchange reaction of cisplatin with core-shell-type poly(citric acid)-b-poly(caprolactone)-b-poly(citric acid) (PCA–PCL–PCA). The resulting polymer–platinum complex nanoparticles showed a high loading capacity (up to 44.2% w/w). The TEM observation confirmed that the nanoparticles with spherical shape were formed by the mixing of PCA–PCL–PCA copolymer and cisplatin. According to TEM and DLS, polymer–cisplatin complex nanoparticles showed larger diameters compared with empty block copolymer attributed to some intermolecular crosslinkings through polymer–platinum (II) complex formation. The release profile of the platinum (II) complexes in phosphate-buffered saline medium at 37 °C indicated sustained manner of drug release. In vitro cytotoxicity evaluated by MTT assay, demonstrated that the PCA–PCL–PCA block copolymer does not exhibit apparent cytotoxicity. PCA–PCL–PCA–cisplatin complex nanoparticles showed greater cytotoxicity to HeLa cell line contrasted with free cisplatin, attributed to existence of poly (citric acid) moiety.