The present invention provides a composition comprising a sPLA2 hydrolysable liposome, an exterior solution, and an interior solution within the liposome, —wherein the concentration of osmolytes is higher in the interior solution than in the exterior solution. The composition improves storage stability of sPLA2 hydrolysable liposomes, in particular at when stored at 2-8 degrees Celsius. The liposome preferably encapsulates cisplatin. The invention also provides methods of preparing the composition of the invention.
