A method for preparing a closed vesicle by a rehydration of a closed vesicle using a rehydration solution, wherein said closed vesicle comprises a dehydrated micelle particle or dehydrated amphipathic micelle bilayers, preferably a liposome loading a pharmaceutically active substance, and the method is characterized in that the rehydration is carried out at a low temperature such as in the range of from 0 C. to 10 C. The method can provides a rehydrated stable vesicle without a leak of the loaded substance.