[Concentration of cefotaxime and its metabolite in human bone marrow blood]

Cefotaxime (CTX) was intravenously administered in an amount of 2.0 g to each of 34 adult patients before the surgery mainly of the hip joint. Samples of the blood from the bone marrow around the trochanter were taken at the time of the operation. At the same time blood samples were taken from peripheral veins. The sample was centrifuged and the supernatant was analyzed for CTX and desacetyl-CTX. The concentration of CTX in the marrow blood was 150.9 micrograms/ml and that in the blood was 182.5 micrograms/ml in the earliest samples taken at 20 minutes after injection. In the 44 pairs of samples, the concentration of CTX in the marrow blood was lower than that in the peripheral blood in all the cases except 4. The concentration of desacetyl-CTX (Des-CTX), however, in the marrow blood was higher than in the peripheral blood in 33 of the 44 pairs of specimens. Since the degradation of the drug progresses with time, the ratio of Des-CTX to CTX increased with time. This trend was particularly marked in the bone marrow blood and can be expressed as Y = 113.0 + 0.32 t, when Y is the ratio percentage (Des-CTX/CTX) and t is time after the injection of the drug in minute. Thus, CTX transferred into the bone marrow tends to remain there and transformed into the desacetyl form.