Antitumor effect and pharmacokinetics of intraperitoneal NK105, a nanomicellar paclitaxel formulation for peritoneal...

The intraperitoneal administration of paclitaxel has been shown to be a promising treatment strategy for peritoneal malignancy. The present study evaluated the effects of intraperitoneal administration of NK105, a paclitaxel-incorporating micellar nanoparticle, which has been shown to have a remarkable effect in a mouse model of gastric cancer. Intraperitoneal NK105 significantly reduced peritoneal tumors in vivo compared with the conventional paclitaxel formulation of paclitaxel solubilized in Cremophor EL and ethanol (PTX-Cre). Moreover, intraperitoneal NK105 significantly reduced the size of subcutaneously inoculated tumors, whereas no such effect was seen with PTX-Cre. Similar systemic toxic effects were observed following the intraperitoneal administration of both NK105 and PTX-Cre. Although NK105 disappeared rapidly almost within a day from the peritoneal cavity, the paclitaxel concentration in peritoneal nodules 4 h after intraperitoneal administration was significantly higher in the NK105 group than in the PTX-Cre group (P < 0.05), whereas there were no significant differences in liver paclitaxel concentrations between the two groups. We also evaluated the pharmacokinetics following intraperitoneal administration of NK105 and PTX-Cre. Serum paclitaxel concentrations 6, 12, 24, and 48 h after the intraperitoneal administration of the drugs were significantly higher in the NK105 than the PTX-Cre group. Furthermore, the peak serum concentration was higher in the NK105 than PTX-Cre group (24 100 ± 3560 vs 108 ± 25 ng/mL, respectively; P < 0.001), as was the area under the concentration-time curve from 0 to 48 h (191 000 ± 32 100 vs 1500 ± 108 ng·h/mL, respectively; P < 0.001). Therefore, intraperitoneal chemotherapy with nanoparticulate paclitaxel NK105 may offer a novel treatment strategy for improving drug delivery in gastric cancer with peritoneal dissemination because of enhanced drug penetration into peritoneal nodules and its prolonged presence in the systemic circulation.