Plasma Protein Binding

The binding of drug to plasma proteins is a major determinant of drug disposition and plays an important effect on pharmacodynamics since only the free (unbound) drug is responsible for the pharmacological activity.

The proteins commonly involved in binding with drugs are albumin, lipoproteins, and a1-acid-glycoprotein (AGP). Acidic and neutral compounds will tend to bond with albumin, while basic substances will primarily bind to the acidic AGP molecule.

Assay Methodology

At Quintara Discovery, plasma protein binding for a test compound is determined using the Rapid Equilibrium Dialysis (RED) method performed in a 48-well format.

Plasma Protein Binding: Standard Assay Conditions (Customizable)

Testing Compound Concentration
1 μM

Dialysis buffer
PBS, pH 7.4

Incubation Period
4 hour at 37 °C, 10% CO2 if needed

Detection Method

Control Compound

Human, rat, mouse, dog and monkey (additional species are available on request)

% Bound

Turnaround Time
2-3 Days

Compound requirements
20 μL 10 mM DMSO stock