In vitro binding of amantadine to plasma proteins

In vitro binding of amantadine to plasma protein was assessed by ultrafiltration of plasma samples (from a blood bank) to which amantadine hydrochloride had been added. Approximately two-thirds of the amantadine was found to be protein-bound. The degree of protein binding was constant over a plasma amantadine concentration range of 100-2,000 ng/ml.