 The first MMP inhibitors that were tested in patients were Ilomastat and Batimastat, hydroxamate-based MMP inhibitors.However, neither compound showed good oral bioavailability.Thus far, Periostat (active ingredient is doxycycline hyclate) is the only MMP inhibitor that has been approved by the U.S. Food and Drug Administration (FDA).It is used for the treatment of periodontitis.