Piroxicam bioadhesive ocular inserts: physicochemical characterization and evaluation in prostaglandin-induced...

An attempt has been made in the present research to formulate piroxicam into bioadhesive ocular inserts with an objective to sustain drug release, reduce frequency of dosing, and enhance ocular bioavailability of piroxicam.

Drug matrices were prepared using film forming polymer, PVP and bioadhesive polymers, HPMC, CMC, and carbopol. Ocular inserts were prepared by film casting method and prepared films were subjected to investigations for their physical and mechanical properties, swelling behaviors, ex vivo bioadhesion, and in vitro drug release. The optimized formulation was tested and compared with eye drops of piroxicam for ocular anti-inflammatory activity in rabbits against PGE(2)-induced inflammation.

The physicochemical, bioadhesive, and swelling properties of films were found to vary significantly depending on the type of the polymers and their combination. The above properties were found to be optimum for all films; however, formulation containing carbopol 0.5% and HPMC 1% was found to be the best film as it shows good adhesion, acceptable pH, and gives a reasonable drug release (99% at 12 hr). Kinetic studies indicated both diffusion and swelling as mechanism of drug release from this matrix. Further in vivo studies with this formulation indicated a significant inhibition of PGE(2)-induced lid closure and PMN migration as compared to eye drops formulation.

Formulation was found promising, as it sustained the drug release and enhanced the ocular bioavailability of piroxicam as compared to piroxicam eye drops.