Healthy adults (n=20) will be recruited and informed consent will be obtained. Participants will agree to a number of visits, a Baseline Visit, 6 Study Visits, and a follow-up Safety Visit. Each course of study drug will be followed by a washout, but allowed preexisting medications will not be stopped for study participation. A small subset (n=4) of participants will also undergo MRI scanning as a component of their visits following drug administration.