The passage of benorylate into the synovial fluid and tissue of rheumatoid patients.

After a preliminary wash-out period of 3-7 days during which no anti-inflammatory drugs were given, 11 female patients with classical or definite rheumatoid arthritis were given 8 g of benorylate as the 40% suspension 3-7 days prior to synovectomy of the knee. Samples of synovial tissue and fluid from the affected knee were assayed for their content of benorylate, salicylate and paracetamol in an attempt to relat these concentrations to the length of medication and the severity of the disease process as measured clinically, by X-ray, by open inspection at operation and by histology of the synovial tissue. The esterase activity of the blood and synovial fluid was also measured by the capacity to hydrolyse benorylate used as substrate.