Abstract: A phased-release suppository delivery system is disclosed wherein microscopic polymeric “nanospheres” ladened with one or more active agents are homogeneously incorporated within a pharmaceutically acceptable suppository base. The preparation of the “nanospheres” allows the spheres to be transported, substantially intact, across fenestrated membranes such as the capillary membranes of the rectum. The method of preparation of the “nanospheres” allows for the controlled release of active agent(s) only after a substantial number of the spheres have been transported across the capillary membrane of the rectum or other body cavity and have been taken up into the systemic circulation system.