Biapenem pharmacokinetics in healthy volunteers and in patients with impaired renal function

Biapenem (CAS 120410-24-4) is a new broad spectrum antibiotic agent from the group of carbapenem antibiotics. Results of a pharmacokinetic study in eight volunteers, 17 patients with variant degrees of renal impairment and in addition 13 haemodialysis patients, both on (n = 8) and off dialysis (n = 5), are reported. A single dose of 500 mg biapenem was administered i.v. over 30 min; blood and urine samples were collected up to 24 h post infusion in volunteers and up to 48 h in patients. Concentrations were determined by microbiological assay using the cup plate method. The tolerance was good. The renal function in patients was determined using single shot 51chromium-EDTA clearance. The calculation of pharmacokinetic parameters was performed non-compartmentally as well as based on an open two-compartment model. Although the compound is eliminated extrarenally in considerable amounts (approximately 46% in volunteers), an important prolonged elimination in renal dysfunction was found. This was mainly due to decreased renal elimination but also partly due to decreased extrarenal clearance. A dose reduction factor (DRF) is calculated derived from the ratio of the areas under the serum concentration curve (AUC), in normal and impaired renal function. Dosage suggestions are made. The compound is eliminated considerably by haemodialysis. It is therefore recommended that biapenem is given after haemodialysis or in double the dose on haemodialysis days.