10-Hydroxycamptothecin loaded nanoparticles: preparation and antitumor activity in mice.

10-Hydroxycamptothecin (HCPT) loaded nanoparticles made from poly(caprolactone-co-lactide)-b-PEG-b-poly(caprolactone-co-lactide) (PCLLA-PEG-PCLLA) block copolymer, were prepared by a novel two-step nanoprecipitation method using an interior-chemistry strategy. The satisfactory drug loading content (>13%) as well as high encapsulation efficiency (>85%) was achieved. Cytotoxicity test indicated that the HCPT-loaded nanoparticles had enhanced in vitro cytotoxicity compared to free drug. Progressively, in vivo antitumor activity and HCPT biodistribution in sarcoma-180 (S-180) bearing mice after intravenous injection of the HCPT-loaded nanoparticles show that HCPT-loaded nanoparticles exhibited superior in vivo antitumor effect and remarkably different biodistribution than the commercially available HCPT injection.