METHYLPREDNISOLONE DELIVERY BY HYALOBEND(R) CORNEAL SHIELDS AND ITS EFFECTS ON RABBIT OCULAR INFLAMMATION

Release of methylprednisolone from hyaluronic acid derivative corneal shields (Hyalobend(R)), in vitro and in vivo, was evaluated as well as ocular anti-inflammatory activity in the rabbit eye. The release of m ethylprednisolone from Hyalobend(R) corneal shields in vitro followed zero-order kinetics. After placing Hyalobend(R) corneal shields in rab bit eye, aqueous and tear fluid methylprednisolone levels were detecte d up to 48 hours and compared with the levels obtained with methylpred nisolone suspension. Hyalobend(R) corneal shields maintain almost cons tant methylprednisolone levels in the rabbit tear fluid. On the contra ry, the suspension gave very high tear values of steroid concentration s in the first 30 minutes but undetectable in less than 200 minutes. H yalobend(R) corneal shields ensured effective levels of methylpredniso lone into the rabbit aqueous for up to 48 hours. Aqueous levels of dru g, in the group treated with the suspension, decreased progressively a nd after 480 minutes were undetectable. Hyalobend(R) corneal shields s ignificantly reduced the conjunctival inflammation elicited by sodium arachidonate compared with control. Furthermore, Hyalobend(R) corneal shields treatment significantly reduced the levels of PGE(2) in the te ar fluid. Hyalobend(R) corneal shields increase the residence time of methylprednisolone in rabbit tear fluid and enhance the penetration in to the aqueous humor as well as reduced the primary signs of ocular in flammation.