Orbitrap Illustration

Discovery PPB

The discovery phase of pharmaceutical research involves the synthesis and characterization of a large number of new molecular entities (both large and small molecules). The determination of potency through biological assays, and the drug-like properties through drug metabolism and pharmacokinetics (DMPK) are important to deliver a candidate to development. One important parameter determined in discovery is the extent of binding to plasma proteins.

Workflow Overview for Discovery PPB


Plasma-protein binding (PPB) is an early ADME in vitro study that indicates the likelihood of a test compound to bind to proteins in blood plasma. Only the unbound compound is available to act as a drug, making the bound fraction essentially unusable. The basic question to be answered is what percentage of compound is bound to protein in the blood in an in vitro model? 

This is an in vitro study using serum from several species, including human, rat, mouse, or dog as the binding agent. The sample matrices of PPB are the dirtiest of the routine ADME assays and require solvent addition and centrifugation to remove the proteins prior to injection to the LC/MS system. Utilization of on-line sample preparation such as Turboflow™ technology allows for direct injection from the plasma sample matrix, thereby increasing sample throughput and reducing the cost of additional sample prep consumables. The key benefit of the PPB assay is a well supported estimation of the test compound’s affinity to bind protein in the blood without the influence of other in vivo factors present in a live animal such as metabolism and excretion.







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A Novel High Throughput Method Using Full Scan HRAM and Online Extraction for Plasma Protein Binding Determination

Cook K, Dreyer M, et al.
Scientific Poster