AboulFotouh, K. | Search bioRxiv

bioRxiv2022

Development of Dry Powder Formulations of AS01B containing vaccines using Thin-Film Freeze-Drying

AS01B is a liposomal formulation of two immunostimulants namely 3-O-desacyl-4-monophosphoryl lipid A (MPL) and QS-21. The liposomal formulation of AS01B reduces the endotoxicity of MPL and the lytic activity of QS-21; however, it renders the adjuvant sensitive to accidental slow freezing. The liposomal formulation also represents a major challenge towards the formulation of dry powders of vaccines containing AS01B. In the present study, we tested the feasibility of applying thin-film freeze-drying (TFFD) to engineer dry powders of the AS01B liposomal adjuvant alone or vaccines containing AS01B as an adjuvant. Initially, we showed that after the AS01B liposomal adjuvant was subjected to TFFD using sucrose as a stabilizer at 4% w/v, the particle size distribution of AS01B liposomes reconstituted from the dry powder was identical to the liquid adjuvant before drying. We then showed using ovalbumin (OVA) as a model antigen adjuvanted with AS01B (AS01B/OVA) that subjecting the AS01B/OVA vaccine to TFFD and subsequent reconstitution did not negatively affect the AS01B liposome integrity, nor the immunogenicity of the vaccine. Importantly, the thin-film freeze-dried vaccine was not sensitive to repeated freezing-and-thawing. Finally, the feasibility of using TFFD to prepare dry powders of AS01B-adjuvanted vaccines was further confirmed using AS01B-adjuvanted Fluzone Quadrivalent and Shingrix, which contains AS01B. It is concluded that the TFFD technology can enable the formulation of AS01B-adjuvanted vaccines as freezing-insensitive dry powders in single-vial presentation.

pharmacology and toxicology↗

bioRxiv2021

Formulation of Dry Powders of Vaccines Containing MF59 or AddaVax by Thin-Film Freeze-Drying

Oil-in-water (O/W) nanoemulsion-based vaccine adjuvants such as MF59(R) are often used in seasonal and pandemic influenza vaccines. However, vaccines containing nanoemulsions require cold chain for storage and are sensitive to accidental freezing. We explored the feasibility of developing dry powders of vaccines adjuvanted with MF59 or AddaVax, a preclinical grade nanoemulsion that has the same composition and droplet size as MF59, by thin-film freeze-drying (TFFD). AddaVax alone was successfully converted from a liquid to dry powders by TFFD using trehalose as a stabilizing agent while maintaining the droplet size distribution of the AddaVax when reconstituted, whereas subjecting the same AddaVax composition to conventional shelf freeze-drying led to significant aggregation or fusion. TFFD was then applied to convert liquid AddaVax-adjuvanted vaccines containing either model antigens such as ovalbumin and lysozyme, mono-, bi-, and tri-valent recombinant hemagglutinin (rHA) protein-based H1 and/or H3 (universal) influenza vaccine candidates, as well as the MF59-containing Fluad(R) Quadrivalent influenza vaccine to dry powders. Antigens, stabilizing agents, and buffer showed different effects on the physical properties of the vaccines (e.g., mean particle size and particle size distribution) after subjected to TFFD, but the integrity and hemagglutination activity of the rHA antigens did not significantly change and the immunogenicity of reconstituted influenza vaccine candidates was preserved when evaluated in BALB/c mice. The vaccine dry powder was not sensititve to repeated freezing-and-thawing, in contrast to its liquid counterpart. It is concluded that TFFD can be applied to convert vaccines containing MF59 or an nanoemulsion with the same composition and droplet size as MF59 from liquid to dry powders while maintaining the immunogencity of the vaccines, and it may be used to prepare dry powders of multivalent universal influenza vaccines.

pharmacology and toxicology↗