Pulmonary Pharmacology & Therapeutics xxx (2013) 1e4
Contents lists available at ScienceDirect
Pulmonary Pharmacology & Therapeutics journal homepage: www.elsevier.com/locate/ypupt
Intrapulmonary concentration of levofloxacin in patients with idiopathic pulmonary fibrosis Hui Huang a, Yanxun Wang a, Chunguo Jiang a, Liwei Lang b, Hongyun Wang b, Yong Chen a, Yang Zhao a, Zuojun Xu a, * a Department of Respiratory Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, #1 Shuaifuyuan Street, Dongcheng District, 100730 Beijing, China b Department of Clinical Pharmacology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, 100730 Beijing, China
a r t i c l e i n f o
a b s t r a c t
Article history: Received 15 August 2013 Received in revised form 24 October 2013 Accepted 30 October 2013
Patients with idiopathic pulmonary fibrosis (IPF) have significantly impaired pulmonary diffusion, which may affect the pulmonary concentration of many drugs, including antibiotics. In this study, we compared the difference in pulmonary levofloxacin (LVFX) concentration between patients with normal lung function and IPF. The IPF group included 10 patients with a proven diagnosis of IPF and a diffusing capacity for carbon monoxide ranging from 40% to 70% of predicted values. The control group included 10 patients with normal pulmonary function. Blood and bronchoalveolar lavage fluid (BALF) were taken at 3 e3.5 h after fasting. LVFX (500 mg) was administered orally. LVFX concentrations in the serum and BALF were determined using HPLC-MS/MC. The level of LVFX in alveolar epithelial lining fluid (ELF) was calculated using the following formula: LVFX ELF ¼ LVFX BALF (Urea serum/Urea BALF). No significant differences in age, body weight, height, and calculated creatinine clearance and BALF retrieval rate were observed between groups. LVFX serum concentrations in the IPF and control groups were (5.97 1.28) mg/ml and (6.84 3.43) mg/ml, respectively (P ¼ 0.4727). ELF concentration of LVFX in the control group was (27.81 21.36) mg/ml, while the concentration in the IPF group was (10.17 2.46) mg/ml, less than half of that in the controls (P ¼ 0.0058). The intrapulmonary concentration of LVFX in IPF patients was lower than those with normal lung function. Notably, however, the ELF LVFX concentration following 500 mg once-daily exceeded the MIC90 of common respiratory pathogens. Excellent antibacterial efficacy of LVFX can be expected for IPF patients in the treatment of respiratory tract infections. Ó 2013 Published by Elsevier Ltd.
Keywords: Levofloxacin Alveolar epithelial lining fluid Pharmacokinetics Idiopathic pulmonary fibrosis
1. Introduction Idiopathic pulmonary fibrosis (IPF) is the most common disease within the subgroup of idiopathic interstitial pneumonia [1,2]. Despite varying clinical courses, IPF is inevitably associated with a poor prognosis, with a post-diagnosis median survival rate of 2e3 years [3,4]. Pulmonary infection has long been recognized as a complication in patients with IPF, causing acute deterioration and influencing prognosis. Direct measurement of the concentration of antimicrobial agents in alveolar epithelial lining fluid (ELF) would allow for a more informed approach to appropriate dosing of antimicrobial agents for respiratory infections. Recently, more emphasis has been
* Corresponding author. Tel.: þ86 10 69155039; fax: þ86 10 65231169. E-mail address: [email protected] (Z. Xu).
placed on the importance of antimicrobial agent concentration, not only in plasma but also at the site of infection [5,6]. Alveolar ELF, which lies in pools on the inside surface of the alveolus, is a potential infection site in respiratory infection, including pneumonia [7]. There are many factors that can influence antimicrobial penetration into the ELF. Generally, the distribution of anti-infective agents from plasma to ELF has been limited by the alveolar barrier, which consists of lung capillary endothelial cells, connective tissue and alveolar epithelial cells. Histopathologic features in the lung tissue from IPF patients are characterized by type II alveolar epithelial cell hyperplasia, interstitial collagen deposition and architectural distortion in affected areas [8]. These changes can result in significant impairment of pulmonary diffusion function, and may affect the efficacy of many drugs including antibiotics. Very few studies and literature on these issues have been reported. This study aims to compare the difference in pulmonary levofloxacin (LVFX) concentration between patients with normal lung
1094-5539/$ e see front matter Ó 2013 Published by Elsevier Ltd. http://dx.doi.org/10.1016/j.pupt.2013.10.004
Please cite this article in press as: Huang H, et al., Intrapulmonary concentration of levofloxacin in patients with idiopathic pulmonary fibrosis, Pulmonary Pharmacology & Therapeutics (2013), http://dx.doi.org/10.1016/j.pupt.2013.10.004
2
H. Huang et al. / Pulmonary Pharmacology & Therapeutics xxx (2013) 1e4
function and patients with IPF to provide data for rational use of antimicrobial agents in IPF patients. 2. Materials and methods 2.1. Study design and setting This was an open-label investigation conducted at a tertiary hospital in China. The study protocol and informed consent were approved by the ethics committee of Peking Union Medical College Hospital, Beijing, China. Every enrolled patient provided written informed consent for participation in the study. 2.2. Study subjects The IPF group included 10 patients matching the guidelines of 2011 American Thoracic Society (ATS) for the diagnosis and management of IPF [8], and the control group included 10 patients with mild hemoptysis, pulmonary nodular shadows, or chronic cough. All of the patients in the IPF and control groups were scheduled to undergo diagnostic bronchoscopy. For IPF patients, diffusing capacity for carbon monoxide (DLCO) ranged from 40% to 70% predicted and FVC% was more than 50% predicted. For control patients, lung function test results were normal and chest CT was normal or revealed scattered micro-nodules (diameter less than 5 mm). All participants were older than 18 years. All patients of childbearing potential were instructed to take effective contraception during the 2e3 weeks after LVFX administration. Adverse event monitoring occurred through daily phone interviews for 1e2 days after administration and follow-up in the outpatient department 3 days after taking LVFX. Screening tests and examination: A pre- and post-study (after 3 days) evaluation including medical history, physical examination and laboratory testing was performed for every enrolled patient. The laboratory tests consisted of CBC, urinalysis and biochemical tests including blood urea nitrogen (BUN), serum creatinine, blood glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), albumin, total and direct bilirubin level. All patients underwent a lung function test, including FEV1/FVC, FVC, TLC and DLCO and high-resolution chest CT examination. Serum pregnancy test was performed for female patients of childbearing age. Exclusion criteria consisted of the following items: an allergy to fluoroquinolone, administration of fluoroquinolone within 7 days prior to the study, lower creatinine clearance rate (less than 50 ml/ min), clinically significant abnormal laboratory values (white blood cells less than 4.0109/L; AST, ALT, ALP and bilirubin more than 2fold the upper limit of normal range), a past-history of QT interval prolongation, epilepsy or medical condition that would potentially interfere with GI absorption, pregnancy or lactation. Eligible patients were given a single oral dose of LVFX as a 500 mg tablet after a fasting period of at least 6 h. Three to 3.5 h after administration, blood samples were obtained from enrolled patients and bronchoscopy was arranged. Patients were kept fasting until 2 h post-bronchoscopy. 2.3. Specimen processing (1) Blood: An 8 ml blood sample was collected immediately prior to the start of bronchoscopy. After centrifugation, the serum was stored at 80 C for urea and LVFX concentration measurement. (2) Bronchoalveolar lavage fluid (BALF): Patients were prepared for the bronchoscopy with aerosolized lidocaine sprayed into the nasal cavity and oropharynx. During the bronchoscopy
and bronchoalveolar lavage, patients were kept awake without any sedative, and vital signs were monitored throughout the procedure. A total of four 25-ml aliquots of normal saline solution were instilled separately and were immediately aspirated into a trap. The first aspirate was discarded and the second through fourth aspirates were pooled. The total volume of BALF was recorded and centrifuged. The supernatant was stored at 80 C for urea and LVFX level measurement.
2.4. Determination of levofloxacin and urea concentration BUN level in serum and BALF was measured via a modified enzymatic assay (Urea Nitrogen Procedure No. 640; Sigma Diagnostics; St. Louis, MO) and was measured on a spectrophotometer (50 series, Walnut Creek, CA). The standard curves were linear (r2 ¼ 0.99) over a concentration range of 0.1e2.0 mg/dl. The interday and intra-day quality coefficients of variation (CVs) were less than 10%. The level of LVFX in serum and BALF were quantitatively measured via HPLC-MS/MC [9,10]. The assays were linear (r2 ¼ 0.999) over the range of 0.05e10 mg/ml for plasma and 0.02e 4 mg/ml for the BALF. The intra-day and inter-day quality control samples had a CV below 5% for all matrixes. The level of LVFX in alveolar ELF was calculated using the following formula: LVFX ELF ¼ LVFX BALF (Urea serum/Urea BALF). 2.5. Statistical analysis Data were analyzed using the Statistical Analysis System version 9.3 software package (SAS Institute Inc., Cary, North Carolina, USA). Quantitative variables were described using mean standard deviation (SD), and categorical data using frequency and percentage in the text and figures. Comparisons between two groups were analyzed using Student’s t-test when data were normally distributed. Group t-test was used for group data, and paired sample t-test was used for paired data. KruskaleWallis test was used when data were not normally distributed. A value of P < 0.05 was considered to be statistically significant. Data were analyzed and graphed using Graphpad Prism 4 (GraphPad Software, San Diego, CA, USA). 3. Results 3.1. Baseline characteristics of study subjects Twenty-two patients were enrolled in this study, and 20 patients completed the trial. The two cases were excluded from the trial because of a low DLCO. In one IPF patient, their DLCO was 36% predicted and in one control patient DLCO was 70% predicted. No statistically significant differences were seen between the IPF and control groups in height, weight, age, vital signs, concomitant diseases, ECG and calculated creatinine clearance (Ccr). In the IPF group, all 10 subjects were male, but in the control group, there were 5 males and 5 females (P ¼ 0.098). Both DLCO and FVC were lower in the IPF group than in controls (P < 0.001). On physical examination, rales were auscultated in all IPF patients, and 5 IPF patients had clubbing. No abnormal signs were seen in the control cases (P < 0.001). There was significant difference between the two groups with regard to chest CT results (P ¼ 0.0325). All IPF patients displayed typical manifestations of usual interstitial pneumonia. Scattered micro-nodules were seen in four control subjects, a small patchy opacity was observed in the right upper lung in one case, while the other five subjects displayed normal findings on CT (Table 1).
Please cite this article in press as: Huang H, et al., Intrapulmonary concentration of levofloxacin in patients with idiopathic pulmonary fibrosis, Pulmonary Pharmacology & Therapeutics (2013), http://dx.doi.org/10.1016/j.pupt.2013.10.004
H. Huang et al. / Pulmonary Pharmacology & Therapeutics xxx (2013) 1e4
3
Table 1 Baseline characteristics of study participants. Characteristics
IPF group
Control group
Age, y Male sex Height, cm Weight, kg Concomitant disease Abnormal signs Rale Clubbing Normal ECG FVC (% predicted) DLCO (% predicted) Abnormal HRCT results
56.4 8.2 100% 170.8 2.2 75.2 8.0 10%, hypertension
53.5 11.7 50% 165.5 9.1 72.8 13.7 10%, hypertension
100% 50% 90% 71.6 12.5 48.2 6.6 100%
0 0 100% 92.8 4.4 85.3 6.5 50%
P value 0.5305 0.098 0.0912 0.6429 1
Contents lists available at ScienceDirect
Pulmonary Pharmacology & Therapeutics journal homepage: www.elsevier.com/locate/ypupt
Intrapulmonary concentration of levofloxacin in patients with idiopathic pulmonary fibrosis Hui Huang a, Yanxun Wang a, Chunguo Jiang a, Liwei Lang b, Hongyun Wang b, Yong Chen a, Yang Zhao a, Zuojun Xu a, * a Department of Respiratory Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, #1 Shuaifuyuan Street, Dongcheng District, 100730 Beijing, China b Department of Clinical Pharmacology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, 100730 Beijing, China
a r t i c l e i n f o
a b s t r a c t
Article history: Received 15 August 2013 Received in revised form 24 October 2013 Accepted 30 October 2013
Patients with idiopathic pulmonary fibrosis (IPF) have significantly impaired pulmonary diffusion, which may affect the pulmonary concentration of many drugs, including antibiotics. In this study, we compared the difference in pulmonary levofloxacin (LVFX) concentration between patients with normal lung function and IPF. The IPF group included 10 patients with a proven diagnosis of IPF and a diffusing capacity for carbon monoxide ranging from 40% to 70% of predicted values. The control group included 10 patients with normal pulmonary function. Blood and bronchoalveolar lavage fluid (BALF) were taken at 3 e3.5 h after fasting. LVFX (500 mg) was administered orally. LVFX concentrations in the serum and BALF were determined using HPLC-MS/MC. The level of LVFX in alveolar epithelial lining fluid (ELF) was calculated using the following formula: LVFX ELF ¼ LVFX BALF (Urea serum/Urea BALF). No significant differences in age, body weight, height, and calculated creatinine clearance and BALF retrieval rate were observed between groups. LVFX serum concentrations in the IPF and control groups were (5.97 1.28) mg/ml and (6.84 3.43) mg/ml, respectively (P ¼ 0.4727). ELF concentration of LVFX in the control group was (27.81 21.36) mg/ml, while the concentration in the IPF group was (10.17 2.46) mg/ml, less than half of that in the controls (P ¼ 0.0058). The intrapulmonary concentration of LVFX in IPF patients was lower than those with normal lung function. Notably, however, the ELF LVFX concentration following 500 mg once-daily exceeded the MIC90 of common respiratory pathogens. Excellent antibacterial efficacy of LVFX can be expected for IPF patients in the treatment of respiratory tract infections. Ó 2013 Published by Elsevier Ltd.
Keywords: Levofloxacin Alveolar epithelial lining fluid Pharmacokinetics Idiopathic pulmonary fibrosis
1. Introduction Idiopathic pulmonary fibrosis (IPF) is the most common disease within the subgroup of idiopathic interstitial pneumonia [1,2]. Despite varying clinical courses, IPF is inevitably associated with a poor prognosis, with a post-diagnosis median survival rate of 2e3 years [3,4]. Pulmonary infection has long been recognized as a complication in patients with IPF, causing acute deterioration and influencing prognosis. Direct measurement of the concentration of antimicrobial agents in alveolar epithelial lining fluid (ELF) would allow for a more informed approach to appropriate dosing of antimicrobial agents for respiratory infections. Recently, more emphasis has been
* Corresponding author. Tel.: þ86 10 69155039; fax: þ86 10 65231169. E-mail address: [email protected] (Z. Xu).
placed on the importance of antimicrobial agent concentration, not only in plasma but also at the site of infection [5,6]. Alveolar ELF, which lies in pools on the inside surface of the alveolus, is a potential infection site in respiratory infection, including pneumonia [7]. There are many factors that can influence antimicrobial penetration into the ELF. Generally, the distribution of anti-infective agents from plasma to ELF has been limited by the alveolar barrier, which consists of lung capillary endothelial cells, connective tissue and alveolar epithelial cells. Histopathologic features in the lung tissue from IPF patients are characterized by type II alveolar epithelial cell hyperplasia, interstitial collagen deposition and architectural distortion in affected areas [8]. These changes can result in significant impairment of pulmonary diffusion function, and may affect the efficacy of many drugs including antibiotics. Very few studies and literature on these issues have been reported. This study aims to compare the difference in pulmonary levofloxacin (LVFX) concentration between patients with normal lung
1094-5539/$ e see front matter Ó 2013 Published by Elsevier Ltd. http://dx.doi.org/10.1016/j.pupt.2013.10.004
Please cite this article in press as: Huang H, et al., Intrapulmonary concentration of levofloxacin in patients with idiopathic pulmonary fibrosis, Pulmonary Pharmacology & Therapeutics (2013), http://dx.doi.org/10.1016/j.pupt.2013.10.004
2
H. Huang et al. / Pulmonary Pharmacology & Therapeutics xxx (2013) 1e4
function and patients with IPF to provide data for rational use of antimicrobial agents in IPF patients. 2. Materials and methods 2.1. Study design and setting This was an open-label investigation conducted at a tertiary hospital in China. The study protocol and informed consent were approved by the ethics committee of Peking Union Medical College Hospital, Beijing, China. Every enrolled patient provided written informed consent for participation in the study. 2.2. Study subjects The IPF group included 10 patients matching the guidelines of 2011 American Thoracic Society (ATS) for the diagnosis and management of IPF [8], and the control group included 10 patients with mild hemoptysis, pulmonary nodular shadows, or chronic cough. All of the patients in the IPF and control groups were scheduled to undergo diagnostic bronchoscopy. For IPF patients, diffusing capacity for carbon monoxide (DLCO) ranged from 40% to 70% predicted and FVC% was more than 50% predicted. For control patients, lung function test results were normal and chest CT was normal or revealed scattered micro-nodules (diameter less than 5 mm). All participants were older than 18 years. All patients of childbearing potential were instructed to take effective contraception during the 2e3 weeks after LVFX administration. Adverse event monitoring occurred through daily phone interviews for 1e2 days after administration and follow-up in the outpatient department 3 days after taking LVFX. Screening tests and examination: A pre- and post-study (after 3 days) evaluation including medical history, physical examination and laboratory testing was performed for every enrolled patient. The laboratory tests consisted of CBC, urinalysis and biochemical tests including blood urea nitrogen (BUN), serum creatinine, blood glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), albumin, total and direct bilirubin level. All patients underwent a lung function test, including FEV1/FVC, FVC, TLC and DLCO and high-resolution chest CT examination. Serum pregnancy test was performed for female patients of childbearing age. Exclusion criteria consisted of the following items: an allergy to fluoroquinolone, administration of fluoroquinolone within 7 days prior to the study, lower creatinine clearance rate (less than 50 ml/ min), clinically significant abnormal laboratory values (white blood cells less than 4.0109/L; AST, ALT, ALP and bilirubin more than 2fold the upper limit of normal range), a past-history of QT interval prolongation, epilepsy or medical condition that would potentially interfere with GI absorption, pregnancy or lactation. Eligible patients were given a single oral dose of LVFX as a 500 mg tablet after a fasting period of at least 6 h. Three to 3.5 h after administration, blood samples were obtained from enrolled patients and bronchoscopy was arranged. Patients were kept fasting until 2 h post-bronchoscopy. 2.3. Specimen processing (1) Blood: An 8 ml blood sample was collected immediately prior to the start of bronchoscopy. After centrifugation, the serum was stored at 80 C for urea and LVFX concentration measurement. (2) Bronchoalveolar lavage fluid (BALF): Patients were prepared for the bronchoscopy with aerosolized lidocaine sprayed into the nasal cavity and oropharynx. During the bronchoscopy
and bronchoalveolar lavage, patients were kept awake without any sedative, and vital signs were monitored throughout the procedure. A total of four 25-ml aliquots of normal saline solution were instilled separately and were immediately aspirated into a trap. The first aspirate was discarded and the second through fourth aspirates were pooled. The total volume of BALF was recorded and centrifuged. The supernatant was stored at 80 C for urea and LVFX level measurement.
2.4. Determination of levofloxacin and urea concentration BUN level in serum and BALF was measured via a modified enzymatic assay (Urea Nitrogen Procedure No. 640; Sigma Diagnostics; St. Louis, MO) and was measured on a spectrophotometer (50 series, Walnut Creek, CA). The standard curves were linear (r2 ¼ 0.99) over a concentration range of 0.1e2.0 mg/dl. The interday and intra-day quality coefficients of variation (CVs) were less than 10%. The level of LVFX in serum and BALF were quantitatively measured via HPLC-MS/MC [9,10]. The assays were linear (r2 ¼ 0.999) over the range of 0.05e10 mg/ml for plasma and 0.02e 4 mg/ml for the BALF. The intra-day and inter-day quality control samples had a CV below 5% for all matrixes. The level of LVFX in alveolar ELF was calculated using the following formula: LVFX ELF ¼ LVFX BALF (Urea serum/Urea BALF). 2.5. Statistical analysis Data were analyzed using the Statistical Analysis System version 9.3 software package (SAS Institute Inc., Cary, North Carolina, USA). Quantitative variables were described using mean standard deviation (SD), and categorical data using frequency and percentage in the text and figures. Comparisons between two groups were analyzed using Student’s t-test when data were normally distributed. Group t-test was used for group data, and paired sample t-test was used for paired data. KruskaleWallis test was used when data were not normally distributed. A value of P < 0.05 was considered to be statistically significant. Data were analyzed and graphed using Graphpad Prism 4 (GraphPad Software, San Diego, CA, USA). 3. Results 3.1. Baseline characteristics of study subjects Twenty-two patients were enrolled in this study, and 20 patients completed the trial. The two cases were excluded from the trial because of a low DLCO. In one IPF patient, their DLCO was 36% predicted and in one control patient DLCO was 70% predicted. No statistically significant differences were seen between the IPF and control groups in height, weight, age, vital signs, concomitant diseases, ECG and calculated creatinine clearance (Ccr). In the IPF group, all 10 subjects were male, but in the control group, there were 5 males and 5 females (P ¼ 0.098). Both DLCO and FVC were lower in the IPF group than in controls (P < 0.001). On physical examination, rales were auscultated in all IPF patients, and 5 IPF patients had clubbing. No abnormal signs were seen in the control cases (P < 0.001). There was significant difference between the two groups with regard to chest CT results (P ¼ 0.0325). All IPF patients displayed typical manifestations of usual interstitial pneumonia. Scattered micro-nodules were seen in four control subjects, a small patchy opacity was observed in the right upper lung in one case, while the other five subjects displayed normal findings on CT (Table 1).
Please cite this article in press as: Huang H, et al., Intrapulmonary concentration of levofloxacin in patients with idiopathic pulmonary fibrosis, Pulmonary Pharmacology & Therapeutics (2013), http://dx.doi.org/10.1016/j.pupt.2013.10.004
H. Huang et al. / Pulmonary Pharmacology & Therapeutics xxx (2013) 1e4
3
Table 1 Baseline characteristics of study participants. Characteristics
IPF group
Control group
Age, y Male sex Height, cm Weight, kg Concomitant disease Abnormal signs Rale Clubbing Normal ECG FVC (% predicted) DLCO (% predicted) Abnormal HRCT results
56.4 8.2 100% 170.8 2.2 75.2 8.0 10%, hypertension
53.5 11.7 50% 165.5 9.1 72.8 13.7 10%, hypertension
100% 50% 90% 71.6 12.5 48.2 6.6 100%
0 0 100% 92.8 4.4 85.3 6.5 50%
P value 0.5305 0.098 0.0912 0.6429 1
