the bpd the new external medium should also include one or more of the protective sugars in the case of dehydration without prior freezing if the liposomes being dehydrated have multiple lipid layers and if the dehydration is carried out to an end point where there is sufficient water left in the preparation so that a substantial portion of the membranes retain their integrity upon rehydration the use of one or more protective sugars may be omitted it has been found preferable if the preparation contains at the end of the dehydration process at least about 2 and most preferably between about 2 and about 5 of the original water present in the preparation prior to dehydration once the liposomes have been dehydrated they can be stored for extended periods of time until they are to be used when the dehydrated liposomes are to be used rehydration is accomplished by simply adding an aqueous solution e g distilled water to the liposomes and allowing them to rehydrate in making storage stable bpd containing liposomes the liposomes can be loaded with bpd for example using conventional techniques dehydrated for purposes of storage shipping and the like and then rehydrated at the time of use when the dehydrated liposomes are to be used rehydration is accomplished by simply adding an aqueous solution e g distilled water or an appropriate buffer to the liposomes and allowing them to rehydrate the liposomes may be resuspended into the aqueous solution by gentle.