Characterization of Submicron (0.1–1 μm) Particles in Therapeutic Proteins by Nanoparticle Tracking Analysis

Single‐Particle Tracking for Understanding Polydisperse Nanoparticle Dispersions

“…A commercially available instrument designed by Malvern (NanoSight, Malvern) that has recently become available for the characterization of cellular exosomes and other sub-micrometer particles was used for the SPT portion of this work. [35,36] Briefly, the particle tracking has been implemented via a chargecoupled device (CCD) camera recording of laser side-scattering off of individual particles. Subsequent image segmentation of the scattering spots allows for location assignment and the tracking of the 2D particle movement.…”

Factors Governing the Accuracy of Subvisible Particle Counting Methods

“…In an attempt to evaluate the individual methods' performance a number of studies have examined different analytical aspects of the corresponding techniques, 12,13,[17][18][19][22][23][24][25][27][28][29][30][31][32][33] but to date, no systematic analysis which includes a comparison between all the different methods using a number of different standard systems, has been carried out. Recently, we reported on the factors governing the precision of subvisible particle measurement methods 26 in a detailed analysis of such an extensive analytical toolbox for subvisible particle characterization.…”

A Comprehensive Evaluation of Nanoparticle Tracking Analysis (NanoSight) for Characterization of Proteinaceous Submicron Particles

“…The size distribution presented a bell-shape profile as normally seen in other studies. 13,20,25 As discussed previously, NTA analysis of a polydisperse sample could compromise the sensitivity for smaller particles, and the number of protein aggregates with sizes <200 nm might be underestimated or completely undetected. After filtration of the samples through 1.2-and 0.22-mm syringe filters, hardly any submicron particles were detected (Fig.…”

“…13 NTA has better peak resolution than DLS and is in a lesser degree affected by the presence of a few large particles, which makes it more suitable for sizing and counting of polydisperse submicron particles in a sample. 20 Along with other analytical methods, NTA has shown applicability and complementarity for characterizing protein aggregates arising in therapeutic protein products under various stress conditions. 9,[21][22][23] Recently, Kotarek et al 24 reported that the peginesatide multiuse vial presentation withdrawn from the market contained significantly higher concentrations of particles characterized by NTA and flow imaging microscopy, although it did not deviate from product specifications in standard physical and chemical testing.…”

“…The NTA technique has been evaluated for characterization of proteinaceous particles in several studies. 13,20,25 The main drawbacks of NTA are the relatively narrow concentration range (approximately 10 7 -10 9 particles/mL) and the scattering noise in solutions at high protein concentrations; thus, sample dilution is required in some cases. However, the particle count and dilution factor may not be in a linear relationship which depends on the diluent used 25 and the reversibility of aggregate formation.…”