Objective: To develop mucoadhesive tablets for the vaginal delivery of progesterone
(P4) to overcome its low oral bioavailability resulting from drug hydrophobicity and
extensive hepatic metabolism.
Methods: The tablets were prepared using mixtures of P4/Pluronic® F-127 solid
dispersion and different mucoadhesive polymers. The tablets were evaluated for physical
properties, swelling index, mucoadhesive properties and drug release kinetics. P4
pharmacokinetic and pharmacodynamic properties were evaluated in female rabbits and
compared with vaginal micronized P4 tablets and intramuscular (IM) P4 injection,
respectively.
Results: The tablets had satisfactory physical properties and their swelling, in vitro
mucoadhesion force and ex vivo mucoadhesion time were dependent on tablet
composition. Highest swelling index and mucoadhesion time were detected for tablets
containing 20% chitosan-10% alginate mixture. Most tablets exhibited burst release
(~25%) during the first 2 h followed by sustained release for ~48 h. In vivo study showed
that chitosan-alginate mucoadhesive tablets had ~2-fold higher P4 mean residence time in
the blood and 5-fold higher bioavailability compared with oral P4. Further, same tablets
showed 2-fold higher myometrium thickness in rabbit uterus compared with IM P4
injection.
Conclusions: These results confirm the potential of these mucoadhesive vaginal tablets
to enhance P4 efficacy and avoid the side effects associated with IM injection.