Of 30 patients scheduled to undergo elective vitreal surgery, five received a single dose of 1000 mg of cefotaxime intramuscularly and 25 received 100 mg subconjuctivally. Specimens of serum and vitreous were collected from 30 minutes to five hours after drug administration, and were assayed for cefotaxime concentration by bioassay and high pressure liquid chromatography. In the five patients who received the intramuscular dose, no cefotaxime or its major metabolite could be detected in the vitreous. In the 25 patients who received the subconjunctival dose, cefotaxime or its metabolite could be only detected in patients with aphakia or in those who previously underwent vitreal surgery. Cefotaxime in intramuscular administration should not be relied upon as appropriate prophylaxis for vitreal surgery. Cefotaxime in subconjunctival administration reaches therapeutic levels in the vitreous only in previously operated eyes.
- vitreal penetration