Millipore Sigma Vibrant Logo
Home>Biopharmaceutical Manufacturing>BioReliance® Product Characterization Services

BioReliance® Product Characterization Services

Ask us a question
Cell Line Development Interlot & Biosimilar Comparability Lot Release & Stability Process & Product Impurities

Assay Packages
Process and Product Impurities
Process Impurity Testing: Polyethylenimine (PEI)


Process Impurities: Don't Let PEI or HCP Derail your Biotherapy


Measuring Residual Levels of Polyethylenimine (PEI)

Get highly sensitive rapid detection of Polyethylenimine (PEI) to prove your therapy meets recommended ICH Q6B guidelines. PEI is routinely used as a transfection reagent to deliver genes into mammalian cells, including Cell and Gene Therapies (CGT). Developers of PEI-employing therapies are required to demonstrate that levels of this impurity have been minimized in their drug substance by well controlled manufacturing processes. With state-of-the-art instrumentation, experienced scientists, and fast turnaround times, we provide you reliable results to push your project forward.

Our PEI Detection Service — How it Works

We combine the separation power of ultra-high-performance liquid chromatography (UHPLC) with the resolution enabled by charged aerosol detection (CAD); called UHPLC-CAD. This approach excels beyond several other methods for detecting PEI, including evaporative light scattering (ELSD), which does not detect PEI at sufficiently low levels. Since PEI has no useable chromophores (it does not absorb light to any useful extent), UV detection is not capable of quantifying PEI in a drug mixture.

Our CAD detection method can be used for molecules that do not possess a chromophore without the need for derivatization. CAD offers a wide linear range of detection, and it can provide a high-level of sensitivity. The response from the detector is nearly uniform for molecules with different structures (UV detection varies based on the amount of light absorbed by each type of molecule).

The assay is performed by:

1. Extracting PEI from the sample matrix

2. Separating the extract into component parts via UHPLC

3. The eluent from the UHPLC is nebulized in the CAD and heated to create dry particles. The particles are charged using a high voltage.

4. The charged particles are collected and measured with an electrometer.

5. Area under curve (AUC) for PEI signal is used to determine concentration.

NOTE: A degree of customization is anticipated for different matrices.

Contact us to discuss your specialized needs and take the next step to securing the future of your biotherapy.

Hear from Our Experts

Get insight into topics that directly impact your success to clinic. Learn more from our white papers, videos, webinars, and posters.

Knowledge Center

Contact Us

Contact our product characterization experts to discuss your specialized needs and take the next step to securing the future of your biotherapy.

Ask Us a Question Connect with Us on LinkedIn