<qa>  What is the dose of PO?Women will be enrolled in the study and followed during the course of a menstrual cycle while taking a dose of 400mg PO twice daily. An initial screening visit will be performed prior to enrollment and participation in the study. Review of medical history as well as blood and urine collection will occur during the screening visit. Once enrolled, participants will have blood and genital tract samples collected once a week for four weeks to assess intracellular concentrations of RAL in the blood and genital tract tissue. 