Full / Empty Particle Ratio
Viral vectors are composed of nucleic acids such as genomic DNA or RNA and proteins such as capsids, and are considered higher-order complexes. Therefore, their structure is even more complex compared to conventional biopharmaceuticals.
This characteristic means that, in addition to the target intact particles, a considerable amount of various components originating from the target substance—such as empty particles, intermediate particles, degradation products, and aggregates—may be present.
Particularly with AAV (adeno-associated virus) vectors, it has become clear in recent years that empty particles affect both efficacy and safety, and they are now recognized as a critical quality attribute (CQA). However, because empty particles are similar in size to intact particles, separating and analyzing them is not straightforward.
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Sedimentation velocity analytical ultracentrifugation (SV-AUC) is an analytical technique that applies high centrifugal force to a solution, continuously records the sedimentation of solutes over time using a detector, and quantitatively evaluates the dispersion state of solute molecules by analyzing the resulting sedimentation patterns. AUC is widely recognized as the gold standard method for measuring the full/empty particle ratio (F/E ratio) of AAV vectors. However, performing AUC requires advanced expertise and highly skilled techniques.
For over 15 years since our founding, we have accumulated extensive experience and a proven track record in AUC, leading the field of viral vector analysis both domestically and internationally. We operate a total of five instruments—Proteome Lab XL-A (equipped with a fluorescence detector), XL-I, and three Optima units—to meet a wide range of needs.
Ultracentrifuge Analyzer（Optima）
Complete identification including intermediate particles
- Using multi-wavelength detection SV-AUC, we can fully characterize the particle distribution within adeno-associated virus (AAV) vector samples.
Ultracentrifugation Analysis for Small Samples
- Using the ultracentrifugal analysis band sedimentation method (BS-AUC), it is possible to determine the ratio of complete particles to empty particles while reducing the required sample volume to approximately one-thirtieth.
Determination of molar absorptivity
- Determining precise molar absorptivity values is extremely important and useful in daily development and viral vector manufacturing. Using SV-AUC, it is possible to determine the molar absorptivity values for both intact viral particles and empty particles. The determined molar absorptivity values can be utilized in routine spectroscopic analysis (UV measurements and various chromatographies) for quantifying target components.
AUC under GMP standards
- In addition to reliability standards, we have been providing Japan's only GxP-compliant (GLP/GMP) analytical services since 2025.