Ocular Tissue Absorption of Clindamycin Phosphate

Clindamycin phosphate, a new semisynthetic antibiotic that is effective in the treatment of toxoplasmosis and of infections caused by Gram-positive bacteria, was found to be highly concentrated in the choroid, iris, and retina of the pigmented rabbit eye after a single intramuscular injection of 75 mg/kg. Drug levels considered adequate for the control of most ocular infections were detectable in the iris, choroid, and retina 24 hours after injection, at which time serum levels were negligible. Subconjunctival injection of clindamycin phosphate also produced sustained high levels of drug in the choroid, iris, and retina; but when 150 mg was injected in a volume of 1 ml, corneal edema and severe inflammation of the conjunctiva resulted. Lesser amounts (15 to 35 mg) injected subconjunctivally produced adequate ocular tissue levels without damage to the conjunctiva or cornea.