Surface Plasmon Resonance (SPR)

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Surface Plasmon Resonance (SPR)

Method Introduction

In the pharmaceutical industry, drugs’ activity is usually based on a molecular interaction with specific receptors or target molecules in the human body. Surface Plasmon Resonance (SPR) allows reliable and detailed characterization of the drug product concerning the specificity and strength of the interaction with the target.

Applications

Surface Plasmon Resonance (SPR) has several important application considerations:

  • A Biacore™ T200 instrument is a classic bioanalytical device based on the SPR principle to study interactions of any kind of molecule. To monitor the interaction between two molecules, one is attached to the sensor surface (dextran-coated sensor chip surface), and the other is free in solution. The SPR optical detection system monitors the change in mass concentration in real time. These changes are recorded as sensorgrams. During sample injection, a positive response can be observed in the sensorgram, as the interacting partner in solution binds to the interaction partner attached to the sensor surface in increasing mass concentration (association phase). The response decreases during dissociation.

    • Concentration determination
      • Absolute concentration (e.g., Protein A/G surface for IgG content)
      • Active concentration (specific target surface)
    • Determination of the strength of an interaction pair; the outcome is binding constants (kon = association rate constant, koff = dissociation rate constant; KD = Affinity)
    • Receptor binding studies (e.g., Fcγ receptors)
    • Feasibility studies for SPR-assay development
    • Comparability and stability studies based on the potency assessment of samples

  • The direct binding assay is the most often used approach for concentration determination. It utilizes a calibration curve prepared by analyzing known concentrations of a reference sample under the same conditions. The drawback is that only the active portion of the sample binds to the surface.

    To determine the relative active concentration (e.g., IgG as a drug product), the assay first determines the absolute protein concentration via a protein A/G surface. Protein A/G has a high affinity for the Fc part of IgG independent of the functionality of the Fab fragments. Stating the reference sample utilized for the calibration curve to be 100% active, the obtained active concentration of the sample can be set in relation to the absolute protein concentration. This is important information for stability studies of IgGs as DP.

  • Therapeutic antibodies and Fc-fusion proteins represent a significant segment of the biopharmaceutical industry and have substantially benefited public health.

    Antibodies bind to a specific target but can also regulate immune responses by interacting with Fc receptors (FcRs). The family of Fc receptors for IgG (FcγRs) is expressed on the surface of various cells and is an essential participant in many immune system effector functions. The receptors differ in their affinity and specificity for immunoglobulin subclasses. For example, antibodies of the IgG1 isotype have the potential to interact with all human Fcγ receptors (Nimmerjahn and Ravetch, 2008).

    There are three major classes of FcγRs depending on the affinity of the receptor to IgG:

    • Fcγ receptor I (CD64) can be found on monocytes and neutrophils. The most distinctive property of FcγRI is its relatively high affinity to IgG.
    • Fcγ receptor II (CD32) is a low-affinity receptor that allows the phagocytosis and endocytosis of immune complexes and B cell activation.
    • Fcγ receptor III (CD16) mediates antibody-dependent cellular cytotoxicity and is an intermediate affinity receptor.

  • Characterization of the binding of therapeutic antibodies to His-tagged captured:

    • human CD64
    • human CD32a
    • human CD16a
    • human FcRn

Quality and Biosafety Level

We provide all our analytical services with the highest quality standards. Experienced scientists carry out each project, and a scientific reviewer comprehensively checks every report or data presentation.

We offer this technology with the following quality and biosafety levels:

R&D level

We offer this method under R&D. Our GRP system assures the highest-quality research standards.

Up to biosafety level 2

This method can be applied to nucleic acids, viruses, cells, viral vectors, including lentiviruses and more.

Analytical Method Development, Qualification and Validation

For common sample types, we can often apply standardized methods with little setup effort. However, when needed, our experienced analytical experts create or optimize custom methods tailored to your active pharmaceutical ingredient, product type and development phase.

Method Development

Our method development approach tailors sample preparation, method settings and data analysis to the needs of your project and sample.

We include representative samples and, where available, suitable reference standards and stressed/degraded materials, allowing our analytical scientists to design a highly suitable, stability-indicating, robust and repeatable method. Upon request, we will compile a detailed description of the method for your records.

Method Qualification

Method qualification is the initial assessment of an analytical procedure’s performance to show its suitability for its intended purpose.

During method qualification, our analytical scientists perform documented testing demonstrating that the analytical procedure meets criteria in several categories. Criteria may include factors such as repeatability, specificity and robustness. We compile a qualification plan and report, including all relevant data.

Method Validation

Under GMP conditions, method validation confirms that an analytical procedure’s performance suits its intended purpose. Depending on the method’s scope, a broad range of method characteristics, such as specificity, accuracy, precision, limit of detection/limit of quantification (LOD/LOQ), linearity and range, is considered.

During method validation, our analytical scientists perform documented testing demonstrating that the analytical procedure consistently produces a result that meets the predetermined acceptance criteria. We compile a validation plan and report that includes all relevant data.

Depending on the development phase, a fit-for-purpose validation approach can be offered, adjusting the validation required efforts in a phase-appropriate way to meet the method’s needs.

Method Verification

Compendial method verification confirms that a compendial method (e.g., from Ph. Eur. or USP) is suitable and reliable for its intended purpose under the specific conditions of the laboratory.

Unlike full method validation, compendial method verification is often considered a partial validation since the method has already undergone extensive testing and validation during its inclusion in the compendium. The extent of method verification depends on the type of method.

During method verification, our analytical scientists perform documented testing demonstrating that the developed analytical method performs adequately for the specific product or matrix being tested and within the specific laboratory where the method will be employed.

Talk to Our Experts or Request a Quote

Our expert team is ready to answer your questions and guide you to the services best suited to your program’s modality, stage and challenge. If your needs are well-defined, we’ll begin the quotation process.

Description

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