[Tissue concentrations of piperacillin in humans]

High serum levels and low degree of protein binding are the main factors which confer upon piperacillin a good distribution in tissues and biological fluids. In CSF, interstitial fluid, pleural and peritoneal fluids, piperacillin levels varied depending on the dose and on local inflammatory conditions; they reached high values ranging from 20 to 50 micrograms/ml corresponding to 18 to 25% of simultaneous serum levels. In bile, high and early levels of piperacillin were achieved, reaching about 1.200 to 3.200 micrograms/ml 100 min after i.v. injection of 2 or 4 g of the drug; in gallbladder wall more than 500 micrograms/g were measured. High tissue concentrations were found after 4 g i.v. of the drug in the renal cortex: 23 to 115 micrograms/g; in prostatic tissue: 70 micrograms/g; in bone: 15 micrograms/g; in cardiac tissue, especially myocardial tissue: 113 micrograms/g. In the female genital tract, the penetration of piperacillin was noticeable; levels of 15 to 45 micrograms/g were measured in uterus, ovary and salpinx: in contrast, placental transfer of piperacillin was limited. In the respiratory tract, the distribution of piperacillin was rapid, and concentrations of 12 to 30 micrograms/ml and 25 to 55 micrograms/g were found in bronchial secretions and bronchial mucosa respectively a 4 g i.v. dose. Studies of piperacillin distribution in the human body indicate that the drug reaches therapeutic levels in most tissues and biological fluids.