The present invention provides enteric ally coated formulations of 6-mercaptopurine that exhibit a delay in release of the 6-mercaptopurine such that substantial release of 6-mercaptopurine does not occur until after passage through the stomach. Optionally, the formulations also comprise a delay coating in addition to the enteric coating that provides an even further delay such that substantial release of 6-mercaptopurine does not occur until after a certain period of time following passage through the stomach. Such a period of time is preferably at least one hour after passage through the stomach. Following the delay imparted by the enteric coating and optional delay coating, the formulations exhibit better bioavailability and faster dissolution than previous formulations.
