Methodologies for Measuring Plasma Protein Binding

This leads to two incorrect assumptions that (i) the absence of human serum represents a protein- or serum-free potency measure (despite 10% fetal calf serum being a component) (ii) the presence of 50% human serum (and 10% PCS) representing the full effect of serum binding [16]. 

Ultrafiltration Simple, rapid, 96-well format. Adsorption issues, protein leakage. [24-27] 

Ultracentrifugation Minimal non-specific binding and osmotic volume shifts. Large plasma volumes required, long assay time, issues such as sedimentation, back diffusion and viscosity. Potential for lipoprotein contamination of plasma water layer. [28, 29] 

Equilibrium Dialysis Standard ED High-throughput, 96-well format. Long incubation time - compound instability and plasma degradation. Issues of pH drift and osmotic volume shifts (can be corrected for). Membrane adsorption/non-specific binding. [30-32] 

Erythrocyte distribution in plasma and buffer No need for mechanism to separate bound and free drug - adsorption issues minimized. For highly bound compounds, analytical precision no longer a prerequisite. Low throughput, more complex assay format. [40] 

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Advances in Methodology for Measuring Plasma Protein Binding 498... 

ADVANCES IN METHODOLOGY FOR MEASURING PLASMA PROTEIN BINDING... 

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