Liposomal retention of a modified anti-inflammatory steroid.

In studies with synthetic lecithins, dipalmitoylphosphatidylcholine was found to be the preferred form for liposomal retention of cortisol esters at 37 degrees C. Cortisol palmitate was retained longer than cortisol octanoate, whereas unesterified cortisol escaped readily from liposomes. Such a liposome composition may allow the controlled release of modified anti-inflammatory agents, particularly when used for intra-articular administration.