Pharmaceutically acceptable liposome-encapsulated busulphan formulations for parenteral administration are provided, as well as such formulations furthermore comprising glutathione and/or at least one glutathione precursor and a process for manufacture of the preparations. The formulations are stable, have improved biodistribution and significantly reduced side effects over those produced by oral administration or parenteral administration of free drug. The formulations are useful as part of stem cell and/or bone marrow transplant conditioning regimens. A method of treatment of a mammal by use of such formulations.