 After completing Visits 1 and 2, eligible subjects will be randomized to one of three groups: 0.1 UC-781 gel, 0.25 UC-781 gel, or a placebo gel 12 per group. A subset of 9 subjects 3 from each group will also participate in a pK sub-study, which will include 6 timepoints Visit 3- pre, 0.25 hr, 2 hr, 4 hr, Visit 3A- 24 hr, and Visit 5- 1 day post-QD dose. During randomization, study staff will be notified if the participant is randomized to the pK substudy. 