[Kinetics of salicylates from the blood to the articular fluid]

A study was made of the salicylate concentrations in samples of blood and articular fluid from 30 patients treated with acetylsalicylic acid. The data were divided in groups according to the diagnosis of the articular diseases and showed no significant differences as regards the salicylate kinetics in the blood. A concentration of 0.3 mg/1 was reached in 6 minutes on the average and the "near maximum" concentration was 23.0 mg/1 on the average. In the articular fluid a concentration of 0.3 mg/1 the salicylates was reached in 10 to 31 minutes. The average maximum concentration as 14.8 mg/1. The findings support the hypothesis that diffusion was the dominant factor in the passage of salicylates from the blood to the articular fluid. The transport varied with the characteristics of the articular diseases. Histopathological changes in the various types of synovitis would alter the biophysical properties of the internal part of the articularcapsule and would thus alter the kinetics of salicylates.