A method for estimation of plasma protein binding using diffusion ordered NMR spectroscopy (DOSY)†

The plasma protein binding (PPB) of a drug plays a key role in both its pharmacokinetic and pharmacodynamic properties. During lead optimisation, medium and high throughput methods for the early determination of PPB can provide important information about potential PKPD profile within a chemotype or between different chemotype series. Diffusion ordered spectroscopy (DOSY) is an NMR spectroscopic technique that measures the diffusion of a molecule through the magnetic field gradient, according to its molecular size/weight. Here, we describe the use of DOSY for a rapid and straightforward method to evaluate the PPB of drug molecules, using their binding to bovine serum albumin (BSA) as a model.