PharmTech: What are the advantages of SPR over existing analytic technologies?
Sundberg: Because SPR detects binding in real time, and sample prep is minimal, there's a tremendous time-saving over, say, ELISA or
high-performance liquid chromatograhy. Variability is low, and the coefficient of variability often falls in the range of
1–5%, even for very crude samples (e.g., cell-culture supernatants). Apart from the improved productivity, SPR also resolves
affinity into its kinetic parameters (on-and off-rates) which enables scientists to assess more clinically relevant parameters
such as recognition and stability of binding to target-binding site.
PharmTech: Could you give us an idea of what sort of time saving you're talking about?
Sundberg: You would get an answer from an ELISA assay in a matter of hours, but SPR could give you an answer within a few minutes (3–10
minutes). For process engineers, this can shave considerable time off process development. Also, unlike HPLC, SPR does not
require you to produce a standard curve, so that essentially SPR enables calibration-free concentration analysis. This is
of great advantage when you have an unstable standard, or if a standard is not available.
PharmTech: What is the future potential of SPR as a PAT tool?
Sundberg: The real-time capability and critical information from SPR would provide a great advantage in PAT applications in the future.
On-line or in-line detection of product with SPR would provide critical information of quality attributes and how these are
affected by process modifications. For example, there have been some academic initiatives that have proven the possibility
of connecting Biacore to bioreactors for continuous monitoring of expression levels over time under various conditions.