Spray dried cubosomes with ovalbumin and Quil-A as a nanoparticulate dry powder vaccine formulation

Abstract

Subunit vaccine formulations are often produced as liquid dispersions through complicated processes. It is desirable, however, to have simple, cheap and up-scalable methods to produce nanoparticulate subunit vaccines in powder form. Here, a simple single-step spray drying process for production of powder cubosome precursors with the model antigen ovalbumin (OVA) and the adjuvant Quil-A is presented. The cubosomes were characterized in vitro and evaluated in vivo by subcutaneous and oral administration for their potential as a vaccine formulation. Hydrated cubosomes had average particle size of 257 ± 8 nm and zeta potential of -18.0 ± 0.6 mV. The powder contained 10.6 ± 0.7% w/w OVA prior to hydration, of which 65 ± 1% was released within the first 20 min in 9.5 mM PBS at pH 7.3, with the remaining OVA gradually released over the following 24 h. Immunization with cubosomes resulted in significantly stronger antigen-specific serum IgG responses (p < 0.01), CD8 T cell expansion (p < 0.0001) and target T cell killing compared to controls when given s.c., and was ineffective orally. This study shows that spray drying is a suitable method for producing nanoparticulate vaccine formulations in dry powder form.

Preparation and Characterization of an Oral Vaccine Formulation Using Electrosprayed Chitosan Microparticles

“…It is inexpensive and obtained by purification of an extract from the bark of the Chilean tree Quillaja saponaria Molina (29). Quil-A has previously been combined with particulates and OVA for oral vaccine delivery where immune responses were observed (30,31).…”

“…After addition of the buffer, 150 µL of supernatant were instantly collected in a 96-well plate and its fluorescence was measured under the same settings as for measuring encapsulation efficiency. For the rest of the time points (15,30,45,60, 90 min and 2, 4, 6, 8, 24, 48 and 72 h), 200 µg of particles were deposited inside each well and 150 µL of 20 mM PBS pH 6.8 at 37˚C (final concentration of 1.33 mg/mL) was added. The 96-well plate was incubated at 37˚C and the fluorescence was measured at each time point.…”

Evaluation of the effects of spray drying parameters for producing cubosome powder precursors

“…To provide effective immunization, peptides need to be delivered in a particulate delivery system [1]. Cubosomes are lipid-based nanoparticles that have been shown in vivo to be a promising delivery system for vaccination [4,5]. They are composed of a highly twisted continuous lipid bilayer with three-dimensional long range order forming two discrete but highly tortuous water channels [5].…”

“…Cubosomes are lipid-based nanoparticles that have been shown in vivo to be a promising delivery system for vaccination [4,5]. They are composed of a highly twisted continuous lipid bilayer with three-dimensional long range order forming two discrete but highly tortuous water channels [5]. Cubosomes are traditionally produced as dispersions in water by fragmentation of bulk cubic phase liquid crystals (top-down) or by self-assembly of certain amphiphilic lipids upon solvent dilution in water (bottom-up) [6].…”

“…Cubosomes are traditionally produced as dispersions in water by fragmentation of bulk cubic phase liquid crystals (top-down) or by self-assembly of certain amphiphilic lipids upon solvent dilution in water (bottom-up) [6]. Recently, however, spray dried cubosome precursors containing the protein ovalbumin (OVA) -a commonly used model peptide antigen -have been reported to form cubosomes in the size-range of 200-300 nm after hydration [5,7]. These cubosomes could furthermore be co-delivered with the adjuvant Quil-A with little effect on their structure and size and were able to stimulate strong humoral and cellular immune responses [5].…”