title: Designing CAF-adjuvanted dry powder vaccines: spray drying preserves the adjuvant activity of CAF01.
abstract: Dry powder vaccine formulations are highly attractive due to improved storage stability and the possibility for particle engineering, as compared to liquid formulations. However, a prerequisite for formulating vaccines into dry formulations is that their physicochemical and adjuvant properties remain unchanged upon rehydration. Thus, we have identified and optimized the parameters of importance for the design of a spray dried powder formulation of the cationic liposomal adjuvant formulation 01 (CAF01) composed of dimethyldioctadecylammonium (DDA) bromide and trehalose 6,6'-dibehenate (TDB) via spray drying. The optimal excipient to stabilize CAF01 during spray drying and for the design of nanocomposite microparticles was identified among mannitol, lactose and trehalose. Trehalose and lactose were promising stabilizers with respect to preserving liposome size, as compared to mannitol. Trehalose and lactose were in the glassy state upon co-spray drying with the liposomes, whereas mannitol appeared crystalline, suggesting that the ability of the stabilizer to form a glassy matrix around the liposomes is one of the prerequisites for stabilization. Systematic studies on the effect of process parameters suggested that a fast drying rate is essential to avoid phase separation and lipid accumulation at the surface of the microparticles during spray drying. Finally, immunization studies in mice with CAF01 in combination with the tuberculosis antigen Ag85B-ESAT6-Rv2660c (H56) demonstrated that spray drying of CAF01 with trehalose under optimal processing conditions resulted in the preservation of the adjuvant activity in vivo. These data demonstrate the importance of liposome stabilization via optimization of formulation and processing conditions in the engineering of dry powder liposome formulations.
authors: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark.
authors: Pall Thor
authors: PT
authors: Ingvarsson
authors: Signe Tandrup
authors: ST
authors: Schmidt
authors: Dennis
authors: D
authors: Christensen
authors: Niels Bent
authors: NB
authors: Larsen
authors: Wouter Leonardus Joseph
authors: WL
authors: Hinrichs
authors: Peter
authors: P
authors: Andersen
authors: Jukka
authors: J
authors: Rantanen
authors: Hanne Mørck
authors: HM
authors: Nielsen
authors: Mingshi
authors: M
authors: Yang
authors: Camilla
authors: C
authors: Foged
mesh_terms: D000276:Adjuvants, Immunologic / Q000737:chemistry*; D000818:Animals; D002412:Cations; D003890:Desiccation; D004339:Drug Compounding / Q000379:methods*; D005260:Female; D006017:Glycolipids / Q000737:chemistry*; D007785:Lactose / Q000737:chemistry; D008081:Liposomes; D008353:Mannitol / Q000737:chemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D011208:Powders; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D011993:Recombinant Fusion Proteins / Q000276:immunology; D014199:Trehalose / Q000737:chemistry; D014612:Vaccines / Q000008:administration & dosage / Q000737:chemistry*
chemical_list: D000276:Adjuvants, Immunologic; C557979:Ag85B-ESAT-6 fusion antigen; D002412:Cations; D006017:Glycolipids; D008081:Liposomes; D011208:Powders; D000644:Quaternary Ammonium Compounds; D011993:Recombinant Fusion Proteins; D014612:Vaccines; C507803:trehalose 6,6'-dibehenate; C015831:dimethyldioctadecylammonium; D008353:Mannitol; D014199:Trehalose; D007785:Lactose