The purpose of this study is to assess vitreous concentrations of nonsteroidal
antiinflammatory drugs (NSAIDs) and prostaglandin E2 in patients treated with NSAIDs before
vitrectomy.
A total of 0.5 to 1 mL undiluted vitreous was removed from the midvitreous cavity at the
beginning of the surgery before infusion with balanced salt solution. Samples were
immediately frozen and stored at -40°C until analysis. Samples were evaluated in a masked
fashion. Vitreous concentrations of the study drugs were quantified using a reverse-phase
liquid chromatography mass spectroscopy system. The minimum quantification limit for
ketorolac, bromfenac, nepafenac, and amfenac was 0.8 ng/mL. Prostaglandin E2 concentrations
were determined using a commercially available competitive enzyme immunoassay kit (R & D
Systems, Minneapolis, MN).