Liposome-incorporated corticosteroids: I. The interaction of liposomal cortisol palmitate with inflammatory synovial membrane.

Cortisol palmitate-containing liposomes were stable in rheumatoid synovial fluid at 37 degrees. Two hours after the intra-articular injection of such liposomes into experimentally arthritic rabbits relatively high proportions of the steroid and lecithin components were recovered from the synovialis. The level of cortisol in the tissue at this time was inversely related to the chronicity of the inflammation. It was found also that the degree and duration of the anti-inflammatory activity of the liposomes was greatest in the initial acute phases of the inflammation.