Is protein binding really so important? And what is plasma protein binding equilibrium dialysis?

Simply put, a drug’s efficiency is affected by the degree to which it binds; the less bound a drug is, the more efficiently it can traverse cell membranes or diffuse.

QUINTA-ANALYTICA uses plasma protein equilibrium dialysis and LC-MS / MS to determine this critical binding for its partners.

The highly effective equilibrium method sees Quinta use a device which has two chambers connected by a membrane with pores that allow only molecules up to a certain size to pass through it.  A sample of plasma or protein with analyte is then pipetted into one chamber, and a buffer is placed into the other.  Once the equilibrium has stabilized, due to the free movement of small molecules and ions across the membrane, its concentration in both chambers is then measured and corresponds directly to the amount of substance which is unbound to the proteins

For drugdevelopment it is critical to fully understand and measure this degree of protein binding of small molecules as it directly affects the rate of excretion of the preparation, in some cases, that can be as much as 95-99%, and in-turn, determines the drugs overall efficacy.

Contact us to learn more!

Additional News

  • 20 November 2025

    Webinar: Streamlined Evidence Strategies for Biosimilars: Analytics, PK and Immunogenicity in focus

    On behalf of Conscio Group, we are pleased to invite you to the upcoming free educational webinar from biosimilar series.

  • 11 September 2025

    Meet us at CPHI 2025

    This October, the global pharmaceutical community will gather in Frankfurt for CPHI 2025. Quinta-Analytica as a member of Conscio Group will be there too – visit us in the Contract Manufacturing Hall 5.1, Stand F1.

  • 8 September 2025

    Quinta-Analytica successfully passed two onsite FDA inspections

    In the first half of 2025, Quinta-Analytica underwent two onsite inspections by the U.S. Food and Drug Administration (FDA).