Developments in the formulation and delivery of spray dried vaccines

Abstract

Spray drying is a promising method for the stabilization of vaccines, which are usually formulated as liquids. Usually, vaccine stability is improved by spray drying in the presence of a range of excipients. Unlike freeze drying, there is no freezing step involved, thus the damage related to this step is avoided. The edge of spray drying resides in its ability for particles to be engineered to desired requirements, which can be used in various vaccine delivery methods and routes. Although several spray dried vaccines have shown encouraging preclinical results, the number of vaccines that have been tested in clinical trials is limited, indicating a relatively new area of vaccine stabilization and delivery. This article reviews the current status of spray dried vaccine formulations and delivery methods. In particular it discusses the impact of process stresses on vaccine integrity, the application of excipients in spray drying of vaccines, process and formulation optimization strategies based on Design of Experiment approaches as well as opportunities for future application of spray dried vaccine powders for vaccine delivery.

Nanoparticle-Based Vaccines Against Respiratory Viruses

“…Intranasal vaccination led to higher antigen-specific lymphocyte proliferation, cytokine production (interferon-γ, interleukins) and induction of antigenspecific IgA antibody (70)(71)(72)(73)(74). A promising formulation strategy is the intranasal spray, which delivers conveniently and safely the nanovaccines directly to the respiratory mucosa (75)(76)(77). However, the number of clinical trials using nanovaccine formulations for intranasal delivery, including spray dried nanovaccines, is limited.…”

“…However, the number of clinical trials using nanovaccine formulations for intranasal delivery, including spray dried nanovaccines, is limited. This is mostly associated with the difficulty of keeping the nanovaccine integrity during the entire formulation process (76). Moreover, the immune response is particularly sensitive to the nature, size, shape, and surface properties of the nanoparticles as well as to the density and the potency of the antigens.…”

Virus-like particle vaccines: immunology and formulation for clinical translation

“…Spray-drying has also gained traction as an alternative vaccine storage mechanism, avoiding the potential mechanical damage induced by freeze-drying by instead forming a dry powder formulation through a combination of nebulization and dehumidification [152]; however, spray-drying involves exposure to elevated temperatures, which can be similarly damaging to thermolabile VLP. HPV VLP suspended in a formulation containing mannitol, trehalose, dextran, L-leucine and inositol are capable of surviving this procedure [153][154][155].…”

Meeting the unmet: from traditional to cutting-edge techniques for poly lactide and poly lactide-co-glycolide microparticle manufacturing

“…Beyond its traditional role of controlled drying process and prominence in the inhalable powders area, current SD technologies may reshape manufacturing of injectable sustained release depots as well, as an alternative to emulsion-freeze-drying technologies (Mundargi et al 2011;Guo et al 2015;Wan and Yang 2016). In particular, SD is slowly emerging as a manufacturing process of controlled delivery systems for biomolecules and vaccines (Mueller et al 2012;Allahyari and Mohit 2016;Kanojia et al 2017). However, in order to climb over the ridge of compliance and controlled release requirements, traditional pitfalls have to be overcome.…”