Targeted delivery of methotrexate to skeletal muscular tissue by thermosensitive magnetoliposomes

Thermosensitive magnetoliposomes (TMs) encapsulated with methotrexate (MTX) were prepared with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and cholesterol by reverse-phase evaporation. Encapsulation efficiency of MTX and hydrophilic magnetite Fe2O3-glu, liposome particle size, zeta-potential, and in vitro and in vivo drug release were studied. More than 80% of loaded MTX was released from TMs within 30 min when the environmental temperature increased from 37 degrees C to 41 degrees C, while 60% of the drug was remained inside TMs for up to 24 h at 37 degrees C. Furthermore, the pharmacokinetics and tissue distribution study showed that TMs significantly increased the accumulation of MTX in the skeletal muscular tissue when exposed to an external constant magnetic field and heated to 41 degrees C compared to the absence of the magnetic field and heating. Therefore, the results in this study suggested that TMs prepared by reverse-phase evaporation can archive a good magnetic targeting effect and fast drug release in response to hyperthermia, which implies their great potential of application in cancer therapy. (C) 2008 Elsevier B.V. All rights reserved.