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ANTONIO L. DOADRIO Y COLS. AN. R. ACAD. NAC. FARM.

Table 2. Average concentrations (mg/mL) of free cefotaxime in rats with
copper

TIME (MIN)

SAMPLES 30 60 90 120 150 180 210

BLOOD 0.65 0.48 0.25 0.12 0.06 0.05 0.03
LIVER 4.47.10–5 2.46.10–5 1.24.10–5 0.88.10–5 0.84.10–5 0.61.10–5 0.25.10–5
SPLEEN 2.59.10–5 1.49.10–5 0.95.10–5 0.50.10–5 0.35.10–5 0.27.10–5 0.23.10–5
KIDNEY 20.6.10–5 9.03.10–5 5.16.10–5 4.01.10–5 3.28.10–5 2.80.10–5 2.64.10–5
LUNG 3.93.10–5 3.46.10–5 2.57.10–5 2.16.10–5 1.24.10–5 1.01.10–5 0.26.10–5
HEART 1.61.10–5 1.39.10–5 1.21.10–5 0.98.10–5 0.87.10–5 0.66.10–5 0.29.10–5

3.3. Stability of cefotaxime

The decrease rate constants of the concentration of free
cefotaxime in treated and control rats are of first-order, according to
the best values of correlation coefficient. The absolute values of the
logarithmic of the observed constants K are shown in Table 4, where
the highest value of log K is in heart for the 2 groups of rats,
therefore the cefotaxime is more stable in heart than in the others
studied organs.

In rats without copper the stability of cefotaxime in organs is
decreasing in the sense: heart and liver > kidney and spleen > lung.
In rats with copper the stability is: heart > kidney > liver, spleen and
lung.

In blood it was observed the lowest stability of cefotaxime in the
2 groups of rats.

Therefore the highest and lowest stability were unaffected by the
presence of copper.

3.4. Activity of cefotaxime

It is not only important the presence of copper in the availability
of cefotaxime, but also the presence of the metal results to be crucial
in the effectiveness of the cephalosporin dosage administrated to the

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