Liposomal formulations of inflammatory bowel disease drugs: local versus systemic drug delivery in a rat model.

Purpose: Based on adherence to intestinal mucosa, intralumenally administered liposomal formulations of 5-aminosalicylate (5-ASA) and 6-mercaptopurine (6-MP) were studied for their potential to enhance local drug delivery to intestinal tissue for the treatment of inflammatory bowel disease.

Methods: 5-ASA was encapsulated in standard phospholipid liposomes while 6-MP required encapsulation in nonphospholipid liposomes to obtain equivalent drug loading. Encapsulation efficiency was measured by size-exclusion chromatography/high-performance liquid chromatogtaphy (HPLC).