Concentrations of ceftibuten in plasma and the respiratory tract following a single 400 mg oral dose

Penetration of anti-infective agents into pulmonary epithelial lining fluid: focus on antibacterial agents

The exposure-response relationship of anti-infective agents at the site of infection is currently being re-examined. Epithelial lining fluid (ELF) has been suggested as the site (compartment) of antimicrobial activity against lung infections caused by extracellular pathogens. There have been an extensive number of studies conducted during the past 20 years to determine drug penetration into ELF and to compare plasma and ELF concentrations of anti-infective agents. The majority of these studies estimated ELF drug concentrations by the method of urea dilution and involved either healthy adult subjects or patients undergoing diagnostic bronchoscopy. Antibacterial agents such as macrolides, ketolides, newer fluoroquinolones and oxazolidinones have ELF to plasma concentration ratios of >1. In comparison, β-lactams, aminoglycosides and glycopeptides have ELF to plasma concentration ratios of ≤1. Potential explanations (e.g. drug transporters, overestimation of the ELF volume, lysis of cells) for why these differences in ELF penetration occur among antibacterial classes need further investigation. The relationship between ELF concentrations and clinical outcomes has been under-studied. In vitro pharmacodynamic models, using simulated ELF and plasma concentrations, have been used to examine the eradication rates of resistant and susceptible pathogens and to explain why selected anti-infective agents (e.g. those with ELF to plasma concentration ratios of >1) are less likely to be associated with clinical treatment failures. Population pharmacokinetic modelling and Monte Carlo simulations have recently been used and permit ELF and plasma concentrations to be evaluated with regard to achievement of target attainment rates. These mathematical modelling techniques have also allowed further examination of drug doses and differences in the time courses of ELF and plasma concentrations as potential explanations for clinical and microbiological effects seen in clinical trials. Further studies are warranted in patients with lower respiratory tract infections to confirm and explore the relationships between ELF concentrations, clinical and microbiological outcomes, and pharmacodynamic parameters.

The penetration of ceftibuten into the respiratory tract

STUDY OBJECTIVE

To determine the penetration of ceftibuten into various respiratory tissues and fluids.

DESIGN

Single-dose, open-label, pharmacokinetic study.

SETTING

Veterans Administration Medical Center.

PATIENTS

Twelve hospitalized men aged 34 to 75 years with a variety of noninfectious pulmonary symptoms/diseases.

INTERVENTIONS

Patients received a single oral dose of ceftibuten, 200 mg, prior to undergoing diagnostic fiberoptic bronchoscopy. Plasma samples for the determination of ceftibuten concentrations were collected pretreatment and up to 12 h postdosing. Nasal secretions, tracheal secretions, BAL fluid, and lung tissue from a biopsy were obtained at bronchoscopy from 2 to 7 h postdosing.

MEASUREMENTS AND RESULTS

Mean pharmacokinetic parameters for ceftibuten in plasma were the following: maximum observed plasma concentration (Cmax), 8.77 microg/mL; time to reach Cmax, 2.2 h; area under the plasma concentration-time curve extraploated to infinity, 49.21 microg/h/mL; and terminal elimination half-life, 3.17 h. These parameters were similar to those obtained in studies using healthy volunteers. Mean penetration of ceftibuten into nasal, tracheal, and bronchial secretions was 47%, 50%, and 30%, respectively. Mean penetration into BAL fluid was 81%, whereas penetration into lung tissue was 39%. No patient experienced any adverse effects related to ceftibuten.

CONCLUSIONS

Ceftibuten penetrates well into various tissues and fluids of the upper and lower respiratory tracts. The results support the activity of ceftibuten in the treatment of upper and lower respiratory tract infections.

Comparison of ceftibuten once daily and amoxicillin-clavulanate three times daily in the treatment of acute exacerbations of chronic bronchitis

In medical practice, antibiotics are generally given empirically for the treatment of acute exacerbations of chronic bronchitis (AECB). To be effective, antibiotic therapy should be broad in spectrum, and it should also cover the common beta-lactamase-producing pathogens. In this multicenter, randomized, investigator-masked study, 469 patients with AECB were randomized (in a ratio of 2:1) to receive 400-mg oral ceftibuten capsules once daily or 500-mg amoxicillin-clavulanate tablets three times daily for 5 to 15 days. Patients receiving ceftibuten were further divided into those who took the capsule with a meal (fed) and those who took the capsule 1 hour before a meal (fasted). Clinical and microbiologic responses were evaluated after treatment at 0 to 6 days (end of treatment) and 7 to 21 days (follow-up). Overall clinical success was determined by cure/improvement of signs and symptoms of AECB at the end of treatment and at follow-up. Overall microbiologic assessment was graded as eradication, persistence, relapse, reinfection, colonization, superinfection, or unassessable. Tolerability was evaluated by grading observed adverse events. The mean duration of treatment was 10.4 days for patients who received ceftibuten and 10.1 days for patients who received amoxicillin-clavulanate. A total of 252 patients receiving ceftibuten and 117 patients receiving amoxicillin-clavulanate were evaluable for clinical efficacy, and 55 patients were evaluable for microbiologic response. Both treatments improved the signs and symptoms of bronchitis, and overall clinical success rates were equivalent for patients treated with ceftibuten (211 of 252 [84%]) and amoxicillin-clavulanate (93 of 117 [79%]) (95% confidence interval [CI], -4.5% to 13.6%). Overall microbiologic eradication rates were also similar for patients treated with ceftibuten (36 of 37 [97%]) and amoxicillin-clavulanate (12 of 14 [86%]) (95% CI, -5.2% to 21.2%). The most frequently reported treatment-related adverse events were gastrointestinal disturbances, which occurred in 15% (47 of 316) and 24% (36 of 152) of patients treated with ceftibuten and amoxicillin-clavulanate, respectively. No significant difference was observed in the ceftibutenfed and ceftibuten-fasted groups in overall clinical assessments of the clinical efficacy population and safety population. In conclusion, 400 mg oral ceftibuten once daily has a similar clinical success rate to 500 mg amoxicillin-clavulanate three times daily, with a trend toward fewer gastrointestinal side effects, in the treatment of patients with AECB.