Large unilamellar vesicles as trehalose-stabilised vehicles forvaccines storage time and in vivo studies

Liposomes, as a pharmaceutical formulation must display a long shelf life. The recombinant heat-shock protein fromMycobacterium leprae (18-kDa hsp) or its N-acylated derivative, when entrapped within or externally associated with largeunilamellar vesicles, acts as a T-epitope source. Freeze-fracture electron microscopy shows unequivocally that trehaloseavoids aggregation and fusion of these vesicles. Formulations containing trehalose retained up to 98% of the entrappedprotein. The highest antibody level is obtained with formulations containing trehalose. The adjuvant effect depends on theliposomal membrane integrity.