Efficacy of an MPC-BMA co-polymer as a nanotransporter for paclitaxel

Background: Paclitaxel (PTX) is administered as a solution in polyoxyethylated castor oil (CO) due to its low water solubility, but solvent-induced side-effects may be severe. Materials and Methods: PMB30W is a co-polymer of 2-methacryloyloxyethyl phosphorylcholine (MPC) and butyl methacrylate (BMA). Cytotoxicities of PTX in PMB30W (PTX-PMB30W) were examined in cell culture and in vivo. Results: PTX-PMB30W and PTX in dimethyl sulfoxide showed similar toxicity in breast cancer cell lines MCF-7, SK-BR-3 and MX-1. Antitumor efficacies of PTX-PMB30W and PTX in CO (PTX-CO) were similar following weekly intraperitoneal administration of 50 mg/kg PTX in nude mice transplanted with MX-1 cells. At 200 mg/kg PTX, all animals died within 1 minute of PTX-CO administration. However, all animals receiving PTX-PBM30W survived. Ulceration occurred following subcutaneous injection of PTX-CO, but injection of PTX-PMB30W did not cause skin changes. Conclusion: Our data suggest that PMB30W can act as an effective PTX nanotransporter.