Cefazolin levels after intravitreal injection. Effects of inflammation and surgery.
Cefazolin (2.25 mg) was injected into the vitreous cavity of phakic, aphakic, and aphakic/vitrectomized rabbits; inflamed eyes were compared to controls. Vitreous levels of cefazolin were determined at selected times from 2 to 48 hr, and the half-life was calculated. The effect of inflammation was to increase the half-life or to reduce the rate of elimination of cefazolin from the vitreous cavity. The drug was cleared substantially faster from aphakic/vitrectomized eyes than from phakic or aphakic eyes. Vitreous levels of cefazolin were above the MIC for most common gram-positive organisms causing endophthalmitis in all study groups at 24 hr, but in only the phakic inflamed eyes and in the aphakic eyes with intact vitreous at 48 hr.
Ficker
L
L
Department of Ophthalmology, Emory University School of Medicine, Atlanta, Georgia 30322.
Meredith
T A
TA
Gardner
S
S
Wilson
L A
LA
D000818:Animals; D001035:Aphakia / Q000378:metabolism / Q000601:surgery*; D002437:Cefazolin / Q000493:pharmacokinetics*; D006207:Half-Life; D007249:Inflammation / Q000378:metabolism*; D011817:Rabbits; D012044:Regression Analysis; D013212:Staphylococcus epidermidis / Q000276:immunology; D014821:Vitrectomy; D014822:Vitreous Body / Q000378:metabolism*
D002437:Cefazolin