Hans Joachim Dr. Scholl

Transintestinal elimination of ciprofloxacin

This study elucidates the routes of elimination of ciprofloxacin and its metabolites in two groups of 5 subjects each, one of healthy volunteers, the other of patients with severe renal failure having a creatinine clearance of 12 ml/min (range 8-16 ml/min). Each subject received one dose of 200 mg ciprofloxacin infused intravenously over 30 min. In an effort to recover the total dose administered, all urine and faeces were collected for the 7 days following dosing. Blood was collected at set intervals after dosing. Serum, urine, and faeces were assayed by high-pressure liquid chromatography for ciprofloxacin and metabolites. The ciprofloxacin serum half-life in healthy volunteers was 3.9 +/- 0.4 h and in patients with marked renal failure 11.2 +/- 2.5 h. The total amount of ciprofloxacin recovered in urine fell by a multiple of 3.4 from 65.3 +/- 10.7% in healthy subjects to 19.0 +/- 15.9% in patients with renal failure, and the metabolites from 12.2 +/- 2.3% in the former group to 5.8 +/- 5.1% in the latter. In contrast, the amount of ciprofloxacin eliminated in faeces increased, by a similar factor, from 11.4 +/- 2.6% in healthy subjects to 37.2 +/- 12.5% in patients with renal failure. The amount of metabolites in faeces increased analogously from 7.3 +/- 1.6 to 26.2 +/- 6.5%. Since ciprofloxacin was administered intravenously and biliary elimination of the drug and its metabolites is negligible, we propose that elimination by faeces is due primarily to transintestinal elimination. This study demonstrates that transintestinal elimination of ciprofloxacin serves as an extrarenal safety factor compensating for reduced elimination by the renal route.

Penetration of Ciprofloxacin and Metabolites into Human Lung, Bronchial and Pleural Tissue after 250 and 500 mg Oral Ciprofloxacin

Ciprofloxacin (CIP) and metabolite concentrations in lung tissue, parietal pleura and bronchial tissue were assessed in 43 adult patients who underwent lung surgery. A single oral dose of CIP was given for prophylaxis of bacterial infections. Two to 6 h prior to tissues sampling, 23 patients received 250 mg and 20 subjects 500 mg of the substance. Blood plasma samples were obtained at the same time as the lung tissue samples. CIP and its metabolites were assayed chemically by high-pressure liquid chromatography (HPLC). After 250 mg CIP, the individual lung tissue CIP concentrations during the 2- to 6-hour post-dose period ranged from 0.5 to 4.8 mg/kg. In 20 of the 23 lung samples, the CIP concentrations were above 1 mg/kg. After 500 mg CIP, the corresponding lung CIP concentrations ranged from 1.6 to 6.0 mg/kg. The CIP lung concentrations were, irrespective of the dose size, between 2 and 7 times higher than the simultaneous blood plasma concentrations. This indicates an excellent penetration of CIP and its metabolites into lung tissue. Bronchial tissue was obtained in 9 cases. Penetration into bronchial mucosa tissue was good as well, as indicated by tissue/plasma ratio values between 1.5 and 4.4. Individual CIP concentrations in the patients given 250 mg CIP, ranged from 1.0 to 1.6 mg/kg. In the patients who received 500 mg, the range was from 1.7 to 3.4 mg/kg. Tissue/plasma ratio values between 0.8 and 2.1 indicated that penetration to pleural tissues was good as well. Metabolite concentrations in all of the tissues assayed (lung, bronchial mucosa, pleural tissue) were low when compared to the concentrations of CIP. The concentrations in lung, pleural and bronchial tissue will probably permit low doses in the treatment of most respiratory tract infections. The broad spectrum of antibacterial activity, the good tissue penetration, chemical stability and the good safety record of the substance means that the drug is potentially a useful agent for perioperative antibiotic prophylaxis.

Elimination of Ciprofloxacin and Three Major Metabolites and Consequences of Reduced Renal Function

The pharmacokinetics and elimination of ciprofloxacin and its three major metabolites desethylene ciprofloxacin (M1), sulfonylciprofloxacin (M2), and oxociprofloxacin (M3) were determined in 18 volunteers with normal and varying degrees of reduced renal functions. One dose of 500 mg ciprofloxacin was given orally. Samples were assayed by high-pressure liquid chromatography. Serum concentrations of both ciprofloxacin and its metabolites were only slightly influenced by the renal function. The serum concentrations of the metabolites were less than 10% of the ciprofloxacin levels, even in reduced renal function, and were overlapping within groups of patients arranged according to renal function. Dialysis reduced the serum concentration of the parent compound and its metabolites. The serum half-life of ciprofloxacin in normal renal function was 5.8 +/- 1.2 h; this rose to 10.8 +/- 2.3 h in the group with clearances of 10-30 ml/min. Compared to the latter group, the t1/2 was lower (7.0 +/- 2.9 h) in the patients with terminal renal failure. The period of monitoring has a distinct consequence for the t1/2 of ciprofloxacin. The shorter t1/2 values emanate if monitoring had stopped after 10 or 12 h. A slower gamma-phase of elimination was observed and this was particularly distinct in subjects with renal functions within the normal range. The total renal elimination of the parent compound and its metabolites was approximately 60% over the 48-hour collection period in normal renal function and was reduced by about 20% in the group with clearances within the range of 10-30 ml/min. In renal impairment, there was a shift towards a higher proportion of the dose being eliminated as M2. M1 contributed only up to 2% of the dose in urine. Irrespective of the renal capacity, the amount of M3 recovered in urine was 3-4%.