Researchers in the Department of Pharmaceutics and Biopharmaceutics at Kiel University in Germany, are using a Zetasizer Nano system from Malvern Instruments in their work on particulate vaccines formulations for administration via the respiratory tract. Dr. Regina Scherließ leads the research group whose many recent publications include ‘PLGA nanoparticles for vaccine delivery to the respiratory tract [1] and ‘Overcoming the challenges of nasal vaccines through intelligent particle engineering’ [2].
“We formulate nanoparticles as antigen carriers and incorporate them into larger particles, known as nano-in-microparticles, or NiM, of a size feasible for deposition in the nose or lung,” explains Dr Scherließ. “We normally work with dry powder formulations, so the NiM will be dried, usually spray dried, at some point in the formulation process. As the particulate antigen carrier has to be taken up as a particle by the relevant immune cells, we mostly target dendritic cells and macrophages. Nanoparticle size is an important criterion for our formulations and we routinely measure this with the Zetasizer Nano.”
Particle size has to be measured directly after preparation and also upon redispersion of the NiM formulation. Redispersion often has to take place in physiological or cell culture media, and at this point the Zetasizer Nano is used to check for aggregates and particle size stability.
“We’ve also used the Zetasizer Nano for another project where we looked at stabilization of haemaglutinin during spray drying,” continued Dr Scherließ, “and as well in a project characterizing chitosan as an adjuvant. Here, we used the Zetasizer to determine the molecular weight of chitosans of different qualities.”
The Malvern Zetasizer range provides both exceptionally high performance and entry level systems that incorporate combinations of a particle size analyzer, zeta potential analyzer, molecular weight analyzer, protein mobility and microrheology measurements. Particles and molecules from less than a nanometer in size to several microns can be analyzed by a range of variants to suit specific applications and budget.