Binding of disopyramide to α1‐acid glycoprotein in plasma measured by competitive equilibrium dialysis

A modification of equilibrium dialysis in which α‐acid glyco‐protein and plasma compete directly for disopyramide has been used in conjunction with binding curves to measure the extent of the α‐acid glycoprotein‐disopyramide interaction. At concentrations in the therapeutic range, 80–90% of disopyramide was bound to α‐acid glycoprotein for plasma from each of six healthy adults. Also, equilibrium dialysis data are presented, indicating that pH does not influence the binding of disopyramide within the therapeutic range