Optimization of an Alum-Adsorbed Vaccine Powder Formulation for Epidermal Powder Immunization

Optimization of an Alum-Adsorbed Vaccine Powder Formulation for Epidermal Powder Immunization
July 2003
Yuh-Fun Maa1 , Cassandra Shu1, Mahmoud Ameri1, Cindy Zuleger1, Jenny Che1, Jorge E. Osorio1, Lendon G. Payne1 and Dexiang Chen1
Pharmaceutical Research
Publisher: Springer Science+Business Media B.V., Formerly Kluwer Academic Publishers B.V.
(1) Present address: PowderJect Vaccines, Inc., Alza Corporation, Madison, Wisconsin, 53711 Mountain View, California, 94043
Abstract Purpose. To develop stable and effective aluminum salt (alum)-adsorbed vaccine powder formulations for epidermal powder immunization (EPI) via a spray freeze-drying (SFD) process.
Methods. Powder properties were determined using particle size analysis, tap density, and scanning electron microscopy. Alum coagulation was monitored via optical microscopy and particle sedimentation. Protein analysis was determined by the BCA protein assay, SDS-PAGE, and an enzyme immunoassay. In vivo immunogenicity and skin reactogenicity were performed on hairless guinea pigs and pigs, respectively.
Results. SFD of hepatitis B surface antigen (HBsAg) adsorbed to aluminum hydroxide or aluminum phosphate using an excipient combination of trehalose/mannitol/dextran produced vaccine powders of dense particles and satisfactory powder flowability and hygroscopicity. This formulation also offered excellent long-term stability to the powder and the antigen. The two most important factors influencing alum particle coagulation are the freezing rate and the concentration of aluminum in the liquid formulation for SFD. The SFD vaccines, when delivered to hairless guinea pigs by EPI or injected intramuscularly after reconstitution, were as immunogenic as the original liquid vaccine. A further study showed that EPI with SFD alum-adsorbed diphtheria-tetanus toxoid vaccine was well tolerated, whereas needle injection of the liquid formulation caused persistent granuloma.
Conclusions. Stabilization of alum-adsorbed vaccine by SFD has important implications in extending vaccination to areas lacking a cold chain for transportation and storage and may also accelerate the development of new immunization technologies such as EPI.
alum adjuvant - powder formulation - spray freeze-drying - epidermal immunization - HBsAg - vaccine
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