Plasma Protein Binding

Plasma protein binding influences the in vivo efficacy and ADMET profile of a drug. The unbound fraction of a drug exhibits its pharmacologic effect. Although plasma proteins serve as vehicles for water-insoluble drugs, excessive binding to plasma proteins will reduce efficacy and prevent drug elimination, which may result in drug accumulation in the body.

CANTEST offers rapid in vitro plasma protein binding testing via ultrafiltration and equilibrium dialysis methods, using LC-MS/MS to determine the percentage of drug bound to plasma proteins. Ultrafiltration or equilibrium analysis is performed at 37°C, using plasma fortified with the test compound. Ultrafiltrate and retentate samples are collected and analyzed by LC-MS/MS. The percentage of drug bound to plasma proteins and mass balance are determined and non-specific binding of test compounds to the ultrafiltration device is also assessed.

The laboratory can perform blood cell partitioning or hematocrit determination of the blood source. Laboratory staff incubates the test compound in the blood source, takes samples for oxidation at pre-determined intervals and prepares plasma samples from the incubated blood. The drug bound to blood cells is quantified following analysis of the samples by LC-MS/MS and the percentage of drug associated with blood cells and blood cell ratio (Cb/Cp) are determined.

CANTEST offers plasma protein binding testing service in human, rat, mouse, monkey, dog and rabbit plasma and blood, which can be conducted according to GLP regulations