[Plasma and tissue concentrations of biphenylacetic acid following 1 week oral fenbufen medication and topical administration of Felbinac gel on the knee joint].

In an randomised study 30 patients were treated during one week before undergoing an elective surgery of the knee joint with 1 or 2 g respectively of 3% Felbinac gel (biphenylacetic acid gel) or oral 300 mg Fenbufen thrice daily. Biphenylacetic acid (BPAA) is the therapeutically active metabolite of the non-steroid anti-inflammatory drug Fenbufen. Plasma concentrations were measured before, during therapy and at the time of the operation.