Vaginal P4 administration poses a viable alternative and has proven to be as effective or even superior to intramuscular P4 with the ability to provide a more site-specific treatment.Currently commercially available vaginal P4 formulations (i.e.suppositories,creams) almost always liquefy and leak immediately once applied at body temperature.Leakage of vaginal formulations can be messy and also lead to a loss of active drug,negatively impacting patient compliance and therapeutic outcomes [1].