Pharmacokinetic analysis of intravitreal ceftriaxone in monkeys

Ocular toxic effects of intravitreally injected ceftriaxone sodium and its rate of clearance after a single dose were studied in rhesus and cynomolgus monkeys. Doses of 2, 2.5, and 3 mg/0.1 mL were injected into the vitreous cavity. Electroretinograms performed 15 minutes, 24 hours, one week, and two weeks after injection were not significantly different from preinjection electroretinograms. Lens opacification occurred in one eye receiving 2.5 mg of ceftriaxone. Histopathologic findings in the retina were normal in all eyes injected intravitreally. Levels of ceftriaxone after a 2-mg intravitreal dose were 609 mg/L at 0 hours, 434 mg/L at 24 hours, and 19 mg/L at 100 hours in the vitreous; and 1 mg/L at 0 hours, 116 mg/L at 24 hours, and 9 mg/L at 100 hours in the aqueous.