Distribution of chloramphenicol in some tissues and extravascular fluids of dogs after oral administration.

Chloramphenicol concentrations were assayed chemically in tissue homogenates, blood, and certain extravascular fluids of Greyhounds killed 1.5, 3, 6, and 12 hours after they were orally given the drug (50 mg/kg). The concentrations of hemoglobin in blood and tissue homogenates were used to estimate "corrected values" to allow for differences in vascularity of the tissues sampled. The distribution of chloramphenicol in the body was not uniform. In all sampled tissues except brain, the initial corrected values were higher than the concentrations in blood. The tissues sampled, in diminishing order of initial corrected value, were lymph node, spleen, pancreas, liver, kidney, lung, muscle, and brain. The persistence of antibiotic in different tissues varied, and in some tissues it was detectable when blood concentrations reached zero. Penetration of chloramphenicol into brain and cerebrospinal fluid was slower than in other tissues and fluids. In aqueous humor and cerebrospinal fluid, concentrations were lower than those in blood, but high concentrations were present in urine. The findings indicated that during chloramphenicol therapy it may be advantageous to select dosage frequencies according to the site of infection.