Mw3538-andrews

Journal of Antimicrobial Chemotherapy (1997) 40, 573–577
Concentrations of levofloxacin (HR 355) in the respiratory tract
following a single oral dose in patients undergoing fibre-optic
bronchoscopy
J. M. Andrewsa, D. Honeybourneb, G. Jevonsa, N. P. Brenwalda, B. Cunninghamb and R. Wisea
Departments of aMedical Microbiology and bThoracic Medicine, City Hospital NHS Trust, Birmingham, UK Concentrations of levofloxacin were measured in bronchial biopsies, alveolar macrophages
(AM), epithelial lining fluid (ELF) and serum following a single oral dose. Concentrations were
measured by a microbiological assay method. A total of 35 patients undergoing fibre-optic
bronchoscopy were studied. Mean serum, AM, ELF and biopsy concentrations were as
follows. 0.5 h: 4.73 mg/L, 19.1 mg/L, 4.74 mg/L and 4.3 mg/kg; 1 h: 6.6 mg/L, 32.5 mg/L, 10.8
mg/L and 8.3 mg/kg; 2 h: 4.9 mg/L, 41.9 mg/L, 9.0 mg/L and 6.5 mg/kg; 4 h: 4.1 mg/L, 27.7 mg/L,
10.9 mg/L and 6.0 mg/kg; and 6–8 h: 4.0 mg/L, 38.4 mg/L, 9.6 mg/L and 4.0 mg/kg respectively.
Mean serum and AM concentrations at 12–24 h were 1.2 and 13.9 mg/L respectively (con-
centrations in biopsy and ELF were only measurable in three of the six patients). These
concentrations exceed the MIC90s of the common respiratory pathogens, Haemophilus
influenzae (0.015 mg/L), Moraxella catarrhalis (0.06 mg/L) and Streptococcus pneumoniae
(1 mg/L) and suggest that levofloxacin should be efficacious in the treatment of community-
and hospital-acquired respiratory infection.
Introduction
Levofloxacin (HR 355), a quinolone antibacterial, is the bilirubin 85 mol/L or a history of encephalopathy).
L-isomer of the racemate ofloxacin.1 In general, it has a Patients with a history of allergy to quinolones, multiple broad spectrum of activity and is equal to or up to four- drug sensitivity or photosensitivity were also excluded.
fold more active than ofloxacin.2 The aim of this study was Patients were also excluded if they were taking antacids, to compare concentrations of levofloxacin at potential sites anticoagulants, iron salts or anti-epileptic drugs.
of respiratory infection, bronchial mucosa, epithelial liningfluid (ELF) and alveolar macrophages (AM) with simulta-neous serum concentrations, up to 24 h after a single 500 This was an open study designed to measure concentra-tions of levofloxacin in bronchial tissues and fluids follow- Materials and methods
ing the administration of a single 500 mg oral dose. Afterovernight fasting (depending on time of administration A total of 35 patients (24 males, 11 females) undergoing of drug) a single 500 mg oral dose was administered with elective diagnostic bronchoscopy were studied. All of the 50 mL of non-aerated water. Patients were allocated patients were over 18 years of age and all of the females randomly into six bronchoscopy groups as follows: Group were post-menopausal. The study was approved by the 1, 0.5 h post-dose; Group 2, 1 h post-dose; Group 3, 2 h Hospital Ethicis Committee and all patients gave written post-dose; Group 4, 4 h post-dose; Group 5, 6–8 h post- Patients were excluded from the study if there was evidence of an active lung infection, if they were receiving antibiotic therapy or if their respiratory status was severelycompromised. Subjects with significant renal impairment A standard pre-medication of 160 mg of 4% nebulized (determined by a serum creatinine of more than 220 lignocaine, 0.6 mg atropine intramuscularly and 2.5–5 mg mol/L), serious hepatic disease (reflected by any one of 1997 The British Society for Antimicrobial Chemotherapy J. M. Andrews et al.
Assay plates were incubated for 18–20 h at 30°C and, after incubation, zones of inhibition were measured and A standard bronchoalveolar lavage (BAL) was performed calculated using an image analyser (Vidas 2.5, Imaging using 200 mL of pre-warmed 0.9% sodium chloride Associates, Thame, UK) programmed to construct a line (divided into four 50 mL aliquots) followed by gentle of best fit using Bennett’s calculation.5 The lower limit of aspiration. The aspirate from the first 50 mL was discarded detection of the assay was 0.06 mg/L. All measurable to avoid contamination of the sample with larger airway concentrations were within the standard curve. Antibiotic fluids and cells,3 and any residual lignocaine which might concentration in the bronchial biopsy was calculated from affect the microbiological assay. The remaining three aspirates were pooled, and then divided into two Tefloncontainers (to avoid the loss of macrophages sticking to surfaces) for analysis. Immediately, in the endoscopy suite, a small sample was removed using silanized glassware and placed in an improved Neubauer counting chamber so that A is the assayed concentration (mg/L), CT is the tissue concentration (in mg/kg), V is the diluent volume (in the number and type of cells present could be determined mL), and W is the weight of tissue (mg).
microscopically. The remaining sample was centrifuged at
400g for 5 min. After centrifugation the supernatant was
separated immediately from the cells. Approximately Calculation of antibiotic concentration in ELF
2 mL of the supernatant was removed for urea estimation.
The urea concentration in the BAL was determined using The remaining fluid was used to measure the concentra- a modified Sigma Diagnostic kit (UV-66, Sigma Chemi- tion of levofloxacin present by freeze drying and reconsti- cals, Poole, UK). The assay was linear over the range tution in HPLC grade distilled water to one-tenth of the 0.01–0.09 mmol/L. The concentration of levofloxacin was original volume. Macrophages were ultrasonicated on ice calculated using the method described by Renard et al.,6 as in a known volume of chilled pH 7 phosphate buffer (100% duty cycles, Misonix Model XL2015, Life ScienceLaboratories, Luton, UK) before assay. Bronchial biopsy tissue was collected into a humidity chamber to avoid loss of moisture from the tissue before weighing.4 Tissue was weighed (discarding any blood-stained tissue) and then BAL is the concentration of antibiotic in BAL ultrasonicated in buffer as previously described. Blood ELF is the concentration of antibiotic in ELF samples were taken at the end of the endoscopy for the assay of levofloxacin and urea. All samples for assay were stored at 4°C in the dark. With the exception of thelavage supernatant, all samples were assayed within 1 h ofcollection.
Calculation of antibiotic concentration inmacrophages Using data derived by Johnson et al.7 antibiotic concentra-tion was determined assuming a mean AM cell volume of Concentrations of levofloxacin were measured using methodology previously externally validated by the R. W.
Johnson Pharmaceutical Research Institute (Raritan, NJ,USA). Briefly, levels were determined using Iso-Sensitest agar (CM471i Unipath, Basingstoke, UK) and Escherichiacoli 4004 (Bayer AG, Wuppertal, Germany). Calibrators, In Table I are summarized the results for the internal internal controls (fixed concentrations prepared from controls and quality assurance samples. These data con-a different weighing of standard material) and quality firm the reliability of the urea and microbiological assay assurance samples (variable concentrations similar to those expected from the patient samples), were prepared The mean lavage volume, lavage urea, macrophage in pooled human serum (Bradsure Biologicals, Lough- count and biopsy weight for the patient samples were borough, UK) for human serum samples, pH 7 phosphate 44.44 mL (S.D. 18.15), 0.052 mmol/L (S.D. 0.034), 2.13 buffer for tissue and macrophage samples and 9% sodium cells/mL (S.D. 2.13) and 8.5 mg (S.D. 3.31), respectively.
chloride for the concentrated BAL samples. The calibrator Concentrations of levofloxacin in serum, biopsy, ELF concentrations were 0.125, 0.25, 0.5, 1 and 2 mg/L. The and AM including site:serum ratios, are summarized in internal control samples were 1.5 and 0.2 mg/L and the Table II. A plot of the corresponding data is shown in the quality assurance samples ranged from 0.15 to 1.8 mg/L.
All samples were assayed in triplicate.
The highest serum and biopsy concentration were seen Levafloxacin concentrations in respiratory tract
Table I. Results for urea and levofloxacin internal controls and levofloxacin quality
Table II. Summary of mean levofloxacin concentrations in serum, biopsy, epithelial
lining fluid (ELF) and alveolar macrophages (AM) in patients undergoing fibre-optic bronchoscopy following a single 500 mg oral dose J. M. Andrews et al.
Figure. Concentrations of levofloxacin in patients undergoing fibre-optic bronchoscopy following a single oral 500 mg dose.
, biopsy; ▲, epithelium lining fluid; , alveolar macrophages; BLQ, below limit of quantification.
1 h post-dose (mean levels 6.6 mg/L and 8.3 mg/L, respec- comparable site:serum ratios (at 4 h post-dose) were found tively). Mean ELF concentrations were very similar at 1, 2, for all three agents except that the AM ratio for levo- 4 and 6–8 h post-dose (10.8, 9.0, 10.9 and 10.1 mg/L, respec- floxacin (9.1:1) was greater than those of ciprofloxacin tively). Highest AM concentrations were recorded 2 h post-dose (mean 41.9 mg/L). In the 12–24 h group levo- The mean serum, biopsy, ELF and AM concentrations floxacin was not detected in biopsy samples in four of the in all of the groups up to 6–8 h exceeded the MIC90s of the six subjects and in ELF from three of the six subjects.
common respiratory pathogens (MIC90s for Streptococcus. Assuming a site:serum ratio of 1 for the biopsy samples pneumoniae, Moraxella catarrhalis and Haemophilus and using the equation to calculate the amount of tissue influenzae were 1, 0.06 and 0.015 mg/L respectively; needed to measure the level of levofloxacin, in all cases the unpublished data), by at least two-fold; this is important amount of tissue obtained at biopsy was insufficient for because earlier quinolones such as ciprofloxacin have only borderline activity. The concentration of levofloxacin Five subjects experienced mild headaches and eight within the AM suggests that the agent will be clinically subjects reported mild dizziness which the investigators active against ‘atypical’ pathogens associated with commu- felt may have been due to the antibiotic.
nity-acquired infections (Chlamydia pneumoniae andMycoplasma pneumoniae MIC90s of 0.5 mg/L).9,10 Discussion
This study suggests that levofloxacin at a dose of 500 mg given twice a day should be effective in a wide range of This study has shown clinically significant pulmonary concentrations of levofloxacin following a single 500 mgdose. Concentrations were below the limit of quantifica- Acknowledgements
tion in the majority of ELF and biopsy samples taken inthe 12–24 h post-dose group.
We would like to acknowledge the help of Dr W. Weber When the results obtained with levofloxacin are and also Dr P. Mendes from Hoechst AG, Frankfurt, compared with those of ciprofloxacin and temafloxacin8 Levafloxacin concentrations in respiratory tract
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Received 7 January 1997; returned 27 February 1997; returned 21 of dilution. Journal of Applied Physiology 60, 532–8.

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