High concentration of dexamethaone in aqueou and vitreou after ubconjunctival injection Original Reearch Article

PURPOE: To determine the dexamethaone concentration in aqueou, vitreou, and erum of patient after a ubconjunctival injection with dexamethaone diodium phophate and to compare the effectivene of a ubconjunctival injection a a method of delivering dexamethaone into the vitreou with that of two previouly teted route: peribulbar injection and oral adminitration. METHOD: In a propective tudy, 50 phakic patient who underwent a par plana vitrectomy received a ingle ubconjunctival injection with 2.5 mg of dexamethaone diodium phophate, aqueou olution (after topical anetheia and a ubconjunctival injection with lidocaine) at varied interval before urgery. An aqueou and a vitreou ample were taken from each patient, and erum ample were collected at multiple time point from nine of 50 patient. Dexamethaone concentration were meaured by radioimmunoaay. REULT: The etimated maximum dexamethaone concentration in the aqueou wa 858 ng per ml at 2.5 hour after injection, and in the vitreou, 72.5 ng per ml at 3 hour. In erum, a mean maximum concentration of 32.4 ng per ml wa meaured at approximately 30 minute after injection. CONCLUION: ubconjunctival injection of 2.5 mg of dexamethaone diodium phophate reulted in an etimated vitreou dexamethaone peak concentration three and 12 time higher, repectively, than after a peribulbar injection of 5 mg of dexamethaone diodium phophate and an oral doe of 7.5 mg of dexamethaone. Thu, a ubconjunctival injection i the mot effective method of delivering dexamethaone into both the anterior and poterior egment of the eye. ytemic drug aborption i coniderable and i of the ame order of magnitude a after peribulbar injection.