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Discovery Plus™ Screening: Plasma Protein Binding

Our Plasma Protein Binding (PPB) Screening studies give you quick, low-cost data for one or more compounds to understand the binding potential of your drug candidate to plasma proteins.

This medium-throughput service allows you to understand the binding properties of your drug early in the discovery process. Moving quickly through drug discovery and development saves you time and money; get data from a Discovery Plus™ screening study quickly to make risk-based decisions faster and get you through the pipeline more efficiently.

Binding of a compound to plasma proteins can potentially affect the pharmacokinetics, efficacy, and toxicity of a drug. This is because only the free unbound form of the drug is available in the body to exert its pharmacological effect, be biotransformed or be excreted. Generally, acidic drugs tend to bind strongly to serum albumin, whereas basic compounds also bind to α-acid glycoprotein (AGP) or lipoprotein. Evaluating the plasma protein binding potential of a drug is an essential component of the drug development process.

Plasma protein binding provides important inputs for test article concentration calculations for definitive in vitro studies. PPB screening studies use Rapid Equilibrium Dialysis to measure fraction unbound (fu), non-specific binding (% recovery) and the plasma stability (% remaining) of your compound. Our medium-throughput screening study design evaluates compounds and a positive control at a single concentration. These compounds are dialyzed against buffer at 37°C for four hours with plasma from up to six different species. Samples are analyzed by LC-MS/MS using relative quantitation.

This service is ideal for compounds that are in the discovery or early development phase. For compounds that will be submitted for regulatory agency approval, please see our definitive in vitro or in vivo Plasma Protein Binding services.

Reaction phenotyping gives sponsors key information about their drug's metabolism/biotransformation pathways

Our Approach to In Vitro PPB Screening Assays

  • Utilizes Rapid Equilibrium Dialysis (RED) methodology
  • Simultaneously evaluate batches of 6-8 compounds and a positive control at a single concentration
  • Up to six different species of plasma at a single concentration
  • Duplicate determinations
  • Positive control included upon request
  • LC-MS/MS analysis
  • Tabular data summary typically provided within 15 business days of method development including:
    • % Fraction Unbound (fu)
    • % Recovery (Mass Balance)
    • % Remaining (Plasma Stability)

Need more info?

Find study design and results overview and comparison of percent bound of known drugs

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Plasma Protein Binding data is requested by the FDA for IND submissions

What definitive in vitro metabolism assays should you be planning next? Get an overview of regulatory expectations for in vitro DDI and metabolism data for IND

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