Particle analysis is not just a requirement in biopharmaceutical development—it’s a critical component that can make or break the safety and efficacy of your drug. When developing protein therapeutics, particles like aggregates over 0.1 mm must be defined and monitored, while in delivery systems, even the vehicles themselves—cells or viruses—qualify as particles. Ignoring or mismanaging this step puts everything, including patient safety, at risk.1
Analytical Techniques in Protein Therapeutics
In protein therapeutics, release testing generally involves a range of analytical methods. These include oligomer analysis by size-exclusion chromatography (SEC), turbidity measurements caused by submicron particles or reversible self-association, subvisible particle analysis via light obscuration (LO), and visual inspection for visible particles. Submicron particle methods are frequently used for extended product characterization and troubleshooting, although their relatively low robustness remains a challenge in QC applications.1
Given the diverse nature of biopharmaceuticals, selecting the right analytical techniques is important. Often, multiple complementary techniques need to be combined to achieve the most accurate results. Moreover, the characteristics of these methods need to evolve with the different stages of drug development to ensure they are applied appropriately for each phase.1
In early development phases, methods should focus on low sample consumption, high throughput, and automation. As the drug progresses through development, more emphasis is placed on stability-indicating properties, robustness, and the statistical relevance of results. By the time the drug reaches late-stage development and release testing, ease of use in regulated environments becomes critical. For release testing, attention narrows to CQAs, as the product has already been thoroughly characterized and control strategies are in place.1
A recently published article provided an update on analytical techniques and approaches, which have emerged in the last decade. The authors also offered a comprehensive overview of the application of particle analysis for the different types of biopharmaceuticals including therapeutic proteins and particulate biopharmaceutical formulations such as virus particles.
Overcoming Challenges in Submicron Particle Analysis
Particle analysis has evolved from targeting only “unwanted” particles (like protein aggregates) to also identifying “wanted” particles, such as cell-based medicinal products (CBMPs), virus-like particles (VLPs), lipid nanoparticles (LNPs), and vaccines. These new products require more precise particle identification methods.1
Despite progress, analyzing submicron particles—especially in complex formulations like LNPs and VLPs—remains difficult. Available techniques for this size range are limited and primarily for characterization purposes. As biopharmaceuticals grow more sophisticated, particle analysis must span a wide range of particle sizes, from nanometers to micrometers, to address product complexity.1
High Contrast Particle Imaging for Visible and Subvisible Analysis
To help overcome some of these challenges with today’s current methods, Halo Labs has developed a particle analysis technique called background membrane imaging (BMI). BMI uses an automated 96-well plate-based approach for the microscopic analysis of particles in the size range above 2 mm.
BMI uses sophisticated image-processing techniques to analyze images and acquire particle data. First it takes a background image of the membrane. Then, after samples are filtered through and particles are captured, the same membrane is re-imaged, this time with particles on the surface. The background image is precisely aligned with the sample image and then subtracted on a pixel-by-pixel basis so that the background texture is eliminated and particles are revealed. Contrast is 10x greater than measurements done in liquid, sizes are calibrated with an electron microscope, and analysis is fully automated.
Recently, BMI has advanced into fluorescence membrane microscopy, which complements BMI by fluorescence imaging options.1
Conclusion
As biopharmaceuticals continue to evolve, the complexity of particle analysis grows. The selection of appropriate particle analysis techniques is no longer just about detecting impurities; it now includes the accurate characterization of essential components, like CBMPs, virus particles, VLPs, LNPs, and vaccines. Understanding how different methods work and choosing the right combination of techniques is critical for ensuring the safety, quality, and efficacy of these advanced therapies.1
Halo Labs’ BMI method offers a breakthrough solution for many of the challenges associated with particle analysis. By eliminating background noise and delivering high-contrast images, BMI enhances the detection of both visible and subvisible particles. This automated technique, with its ability to handle high throughput and provide clear, precise data, represents a significant advancement for biopharmaceutical developers. Incorporating BMI into your particle analysis strategy ensures that you are using the most cutting-edge tools to safeguard the quality of your drug products.1
References
1. Particles in Biopharmaceutical Formulations, Part 2: An Update on Analytical Techniques and Applications for Therapeutic Proteins, Viruses, Vaccines and Cells. Roesch, Alexandra et al. Journal of Pharmaceutical Sciences, Volume 111, Issue 4, 933 – 950. https://www.sciencedirect.com/science/article/pii/S0022354921006894
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