Subconjunctival administration of ceftazidime in pigmented rabbit eyes.

The ocular kinetics of ceftazidime, a third-generation cephalosporin, were examined in phakic and aphakic pigmented eyes of rabbits following subconjunctival injection (100 mg). Peak ceftazidime concentrations (mean +/- SE, n = three to five rabbits per determination) were as follows: phakic eyes, 40.2 +/- 7.3 mg/L in aqueous humor and 11.2 +/- 0.6 mg/L in vitreous humor at one hour; aphakic eyes, 30.5 +/- 4.8 mg/L in aqueous humor and 15.8 +/- 2.4 mg/L in vitreous humor at one hour. The ability of ceftazidime to eliminate an incipient bacterial infection was also studied. Ten aphakic rabbits received intravitreal injections of 50 colony-forming units (cfu) of Pseudomonas aeruginosa. Six of the ten immediately received a subconjunctival injection of ceftazidime (100 mg). At 48 hours following injections, four of four control eyes yielded bacterial counts greater than 6.2 X 10(6) cfu/mL. Of the six that received ceftazidime, five were sterile and one yielded 10 cfu/mL.

Multistrain comparison of three antimicrobial prophylaxis regimens in experimental postoperative Pseudomonas endophthalmitis.

We compared subconjunctivally administered ceftazidime and BMY 28142, two third-generation cephalosporins, to a regimen of gentamicin and cefazolin for their ability to prevent experimental Pseudomonas postoperative endophthalmitis in rabbits. After extracapsular lens extraction, an inoculum of Pseudomonas was injected into the vitreous; one of the three antimicrobial regimens was then administered subconjunctivally. All 25 eyes treated with gentamicin and cefazolin become infected (P = 1). Two of 25 eyes treated with BMY 28142 became infected (P less than .001). None of the 25 eyes treated with ceftazidime became infected (P less than .001).