Surface Plasmon Resonance
Biotherapeutics are a class of complex molecules that require the use of innovative techniques for their characterisation. Biacore technology offers label-free assays that provide precise and reliable concentration and kinetic measurements. This can be applied throughout all stages of product development, from discovery to quality control, including stability studies and batch-to-batch consistency evaluation.
Biacore technology was used to develop and validate assays allowing precise characterisation of several types of biotherapeutics.
First, Biacore was used to determine the active concentration of a mAb by CFCA analysis. Concentrations were calculated from the measured binding rates. CFCA enables active concentration determination without the need for calibration standards. An application of quantification of influenza virus concentration in vaccine samples was developed. The Biacore technique appears to be a suitable method for accurate and precise quantification of HA in vaccine samples. The method was validated according to ICH Q2 requirements in the range 0.0625 – 4 μg/ml and shows good accuracy, precision, linearity and specificity.
The second SPR application was the determination of affinity and kinetic parameters of a monoclonal antibody with Fc receptors expressed on the effector cells. We showed that adalimumab exhibited complex kinetic characteristics and that the binding mechanisms differed between Fcγγ receptors. Binding to FcγγR1 was modelled as a 1:1 reaction while FcγR2a and FcγR3a assumed a steady-state affinity independent of polymorphisms. Our assays showed very good repeatability (intra-run precision) and intermediate precision. Two binding assays were also developed to study the kinetics of adalimumab-TNFa interaction. Similar kinetic and affinity parameters were obtained.
Finally, the Biacore comparability tool allowed the comparison of sensorgrams in terms of kinetics. This technology is very useful in the case of stability studies, batch-to-batch consistency evaluation and biosimilarity determination.