Cephaloridine (CER) and Tobramycin (TOB) concentration in the bone marrow was examined 1, 2, and 3 hours after intramuscular injection of 1g of CER and 60mg of TOB. Concentration in the bone marrow of tibia 1 hour after injection was 26.0±8.927μg/ml in CER (78.5% ratio to serum) and 3.2±0.898μg/ml (87.5% ratio to serum). Concentration in the bone marrow of tibia 2 hours after injection was 20.6±5.003μg/ml in CER (87.3% ratio to serum) and 1.6±0.480μg/ml in TOB (94.1% ratio to serum). Concentration in the bone marrow of tibia 3 hours after injection was 14.8±4.791μg/ml in CER (91.9% ratio to serum) and 1.1±0.337μg/ml in TOB (84.6% ratio to serum). Penetration capacity of CER and TOB into bone marrow of tibia was was excellent.
