The penetration of Piperacillin (PIPC) to the exudate and granulation tissue in carrageenin abscess of rats was examined on days 1 and 5 to investigate the relationship between antibiotic concentration in serum and inflammatory tissue. The results were as follows :
1. Cmax and AUC in the serum, exudate and granulation tissue increased by degrees according to increase of dosage, however, T1/2 was unchanged.
2. AUC in the serum was directly proportional to the dosage, however, the change of AUC in the granulation tissue and exudate was smaller than in the serum. AUC increased 1.5-fold in the granulation tissue and 1.3-fold in the exudate when the dosage was doubled.
3. AUC in the granulation tissue on day 1 was 2-fold higher than on day 5 for each dosage (20mg, 40mg, 80mg/kg i.v.) . AUC increased with the same proportion regardless of inflammatory stages as the dosage increased.
4. From the above results, the concentrations of the granulation tissue were almost the same as serum levels, but increase of the dosage was not reflected in the concentration of the granulation directly and T1/2 was unchanged. Therefore, it was thought that consideration of the administration intervals was important.