Related Experiment Video
Updated: May 5, 2026

Biosensor-based High Throughput Biopanning and Bioinformatics Analysis Strategy for the Global Validation of Drug-protein Interactions
Published on: December 1, 2020
The bioanalytical challenge of determining unbound concentration and protein binding for drugs
1Analytical Pharmaceutical Chemistry, Dept. of Medicinal Chemistry, Uppsala University, BMC Box 574, SE-75123 Uppsala, Sweden. larsbnilsson@hotmail.se.
Abstract:
Knowledge regarding unbound concentrations is of vital importance when exploring the PK and PD of a drug. The accurate and reproducible determination of plasma protein binding and unbound concentrations for a compound/drug is a serious challenge for the bioanalytical laboratory. When the drug is in equilibrium with the binding protein(s), this equilibrium will shift when physiological conditions are not met. Furthermore, the true unbound fraction/concentration is unknown, and there are numerous publications in the scientific literature reporting and discussing data that have been produced without sufficient control of the parameters influencing the equilibrium. In this Review, different parameters affecting the equilibrium and analysis are discussed, together with suggestions on how to control these parameters in order to produce as trustworthy results for unbound concentrations/fractions as possible.
More Related Videos
Related Concept Videos
Drug Distribution: Plasma Protein Binding
Protein-Drug Binding: Determination Methods
Indirect methods involve isolating the bound drug from its free form in biological samples such as blood, serum, or plasma. These techniques aim to measure the percentage of drugs bound to proteins. Equilibrium dialysis is a commonly used method where the free drug concentration at equilibrium is measured by separating the bound...
Nonlinear Pharmacokinetics: Bioavailability and Protein-Drug Binding
To quantify the extent of bioavailability, pharmacologists often use a parameter called .
Physiological Pharmacokinetic Models: Assumption with Protein Binding
Bioavailability Enhancement: Determination and Conceptual Approaches in Overcoming Bioavailability Problems
Drug Concentrations: Measurements
Plasma...

