Large unilamellar vesicles as trehalose-stabilised vehicles for vaccines: storage time and in vivo studies

Liposomes, as a pharmaceutical formulation must display a long shelf life. The recombinant heat-shock protein from Mycobacterium leprae (18-kDa hsp) o r its N-acylated derivative, when entrapped within or externally associated with large unilamellar vesicles, acts as a T-epitope source. Freeze-fractu re electron microscopy shows unequivocally that trehalose avoids aggregatio n and fusion of these vesicles. Formulations containing trehalose retained up to 98% of the entrapped protein. The highest antibody level is obtained with formulations containing trehalose. The adjuvant effect depends on the liposomal membrane integrity. (C) 2000 Elsevier Science B.V. All rights res erved.