Cisplatin-loaded gelatin-poly(acrylic acid) nanoparticles: synthesis, antitumor efficiency in vivo and penetration in tumors.

Cisplatin (CDDP)-loaded gelatin-poly(acrylic acid) (GEL-PAA) nanoparticles were successfully prepared by polymerizing acrylic acid in the presence of gelatin in aqueous solution followed by incorporating CDDP into the formed GEL-PAA nanoparticles through polymer-metal complex formation of CDDP with carboxylic groups in the nanoparticles. The obtained nanoparticles had a spherical shape, with a mean size of about 100 nm, and high drug payload as well as stability. It is found that CDDP can be released from the nanoparticles in a sustained manner with a small initial burst release. In vitro cytotoxicity revealed that CDDP-loaded nanoparticles had similar cytotoxicity to free CDDP after 48 h co-incubation with human colorectal cancer cell line LoVo. In vivo antitumor activity indicated that the nanoparticle formulation was superior in anticancer effect to free CDDP on murine hepatic H22 tumor-bearing mice model through intraperitoneal (i.p.) administration and displayed a dose-dependent antitumor efficacy. Further, the penetration examination of the nanoparticles through tumor tissue revealed that the CDDP-loaded GEL-PAA nanoparticles could only affect the cells near the tumor vasculature after they entered into the tumor tissue.