Intrarenal concentration-time profile of ampicillin after administration of bacampicillin to patients before nephrectomy.

Nineteen patients with renal cancer who were to undergo nephrectomy received a single oral dose of bacampicillin 800 mg at approximately three (N = 5), six (N = 7), or nine (N = 7) hours before nephrectomy. Serum samples were taken at 30, 60, and 90 minutes after administration and at nephrectomy. Urine was collected immediately before operation. Samples of medulla and cortex tissues were immediately and carefully dissected from a healthy part of the removed kidney and homogenized with a buffer solution. All concentrations were determined by bioassay. Bacampicillin was well absorbed, with a mean +/- SD serum concentration of 16.0 +/- 11.4 mg/L at one hour. The concentrations in renal tissues were higher than the serum levels taken at the same time, and the highest concentrations were found in the urine. the mean ampicillin elimination half-life was approximately the same in the cortex, medulla, and urine, (2.7, 2.3, and 2.4 hr, respectively) but it was shorter in the serum (1.4 hr). Bacampicillin 800 mg produced concentrations in the renal tissues that were higher and more sustained than in the serum and were well above the minimum inhibitory concentrations for common urinary pathogens even ten hours after the dose.