Abstract View
Freeze Spray Drying for the Encapsulation of Active Proteins
ALBERTO BALDELLI, Aylin Cidem, Yigong Guo, Hui Xin Ong, Daniela Traini, Anubhav Pratap-Singh, The University of British Columbia
Abstract Number: 103
Working Group: Aerosol Physics
Abstract
Proteins have inherent low stability due to their high molecular weight and complex structure, making protein delivery challenging. Freeze spray drying allows the encapsulation of several proteins. In this study, the influence of the formulation on the properties of freeze spray-dried encapsulated proteins microparticles and their physic-chemical stability is presented.
Formulations used for the encapsulation of proteins through freeze spray drying involve a polymer for shell formation, carriers for preserving the stability of proteins, and amino acids for promoting the particle formation. The components selected were polyvinylpyrrolidone (PVP) as polymer, α-lactose, D-mannitol, and trehalose as carriers, and leucine, trileucine, arginine, tyrosine, and glutamine as amino acids. Several proteins were investigated: Bovine Serum Albumin (BSA), pea protein, whey protein, hemoglobulin, and Angiotensin-converting enzyme 2 (ACE2). Formulations were first sprayed, at -10°C using a double-flow atomizer in liquid nitrogen and, later, freeze-dried.
All analyzed proteins were encapsulated by using PVP, with a molecular weight of 1300 kDa, mannitol, and leucine with ratios of 6:9:2. By decreasing the molecular weight of PVP to 360 and 55 kDa, the stability of BSA decreased of the 55 and 88 %, by analyzing infrared spectra. Employing lactose or trehalose produces microparticles with broken shell and unsuccessful encapsulation. Other amino acids, with a weight percentage of 15 to 25 %, generates similar results; glutamine is the amino acid decreasing BSA stability of 40 %. After performing ELISA, ACE2 encapsulated using a ratio 6:9:2 of PVP, mannitol, and leucine showed to maintain 87% of activity.
We confirmed the impact of the formulation on the stability of proteins encapsulated using freeze-spray drying. We determined the optimal formulation components that maintain the stability and activity of several proteins, including ACE2, a potential treatment for SARS-CoV-2.