Preparation, characterization, and efficacy of thermosensitive liposomes containing paclitaxel.

To increase the anti-tumor activity of paclitaxel (PTX), novel temperature-sensitive liposomes loading paclitaxel (PTX-TSL) were developed. In vitro, characteristics of PTX-TSL were evaluated. The mean particle diameter was about 100 nm, and the entrapment efficiency was larger than 95%. The phase-transition temperature of PTX-TSL determined by differential scanning calorimetry was about 42 °C. The result of in vitro drug release from PTX-TSL illustrated that release rate at 37 °C was obviously lower than that at 42 °C. Stability data indicated that the liposome was physically and chemically stable for at least 3 months at -20 °C. In vivo study, after three injections with hyperthermia in the xenograft lung tumor model, PTX-TSL showed distinguished tumor growth suppression, compared with non-temperature-sensitive liposome and free drug. The results of intratumoral drug concentration indicated that PTX-TSL combined with hyperthermia delivered more paxlitaxel into the tumor location than the other two paxlitaxel formulations. In summary, PTX-TSL combined with hyperthermia significantly inhibited tumor growth, due to the increased targeting efficiency of PTX to tumor tissues. Such approach may enhance the delivery efficiency of chemotherapeutics into solid tumors.