JAC Advance Access originally published online on July 27, 2006
Journal of Antimicrobial Chemotherapy 2006 58(3):684-688; doi:10.1093/jac/dkl304
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
In vitro and in vivo activities of DW-224a, a novel fluoroquinolone antibiotic agent
1 College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University Seoul 151-742, Korea 2 Dong-Wha Pharmaceutical Ind. Co., Ltd Anyang, Gyunggi 430-017, Korea 3 Department of Life Science, The University of Seoul Seoul 130-743, Korea
*Corresponding author. College of Pharmacy, Seoul National University, San 56-1, Shillim-Dong, Kwanak-Gu, Seoul 151-742, Korea. Tel: +82-2-880-7874; Fax: +82-2-872-1795; E-mail: ecchoi{at}snu.ac.kr
Received 8 January 2006; returned 2 June 2006; revised 26 June 2006; accepted 4 July 2006
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and methodsResults and discussionTransparency declarationsReferences |
|---|
Objectives: The objective of the present study was to assess the in vitro and in vivo activities of DW-224a in order to eventually use it as an antibiotic.
Methods: DW-224a was compared with DW286, ciprofloxacin and trovafloxacin. MICs of DW-224a, DW286, ciprofloxacin and trovafloxacin were determined against several groups of clinical isolates. In addition, intraperitoneal infection was induced with various organisms in mice. Test compounds were administered once orally to mice immediately after infection. The 50% protective dose (PD50) was calculated from the survival rates on day 7 after infection.
Results: Against Gram-positive bacteria, the in vitro activity of DW-224a was stronger than those of ciprofloxacin and trovafloxacin, but slightly weaker than that of DW286. Against Gram-negative bacteria, the activity of DW-224a was similar to those of trovafloxacin and DW286, but weaker than that of ciprofloxacin. In experimental systemic infections in mice with various organisms, like DW286, DW-224a demonstrated potent activity against Gram-positive bacteria and somewhat less activity against Gram-negative bacteria.
Conclusions: DW-224a has a broad spectrum of antimicrobial activity, which is especially potent against Gram-positive bacteria.
Keywords: ciprofloxacin , trovafloxacin , DW286 , MICs , PD50
|
Introduction |
|---|
|
TopAbstractIntroductionMaterials and methodsResults and discussionTransparency declarationsReferences |
|---|
The quinolones have evolved from agents used only for the treatment of urinary tract infections (UTIs) to the latest fluoroquinolones with a remarkably broad spectrum of activity and excellent pharmacokinetics allowing for once-daily dosing and thus improving patient compliance.1 These compounds have been prescribed extensively for the treatment of respiratory tract infections, UTIs, sexually transmitted diseases and infections of the skin and soft tissue.2 However, as use of fluoroquinolones has increased, the continuous increase in the resistance among bacteria is generally recognized.3–5 The development of new antibacterial substances thus appears of utmost importance. Actually many different approaches are taken to develop new compounds. The targets in fluoroquinolone research during the past few years include improving the pharmacokinetic properties, increasing the activity against Gram-positive cocci and anaerobes and against fluoroquinolone-resistant strains, and improving activity against non-fermentative Gram-negative species.1
Several new candidates have been developed in such an attempt by the R&D Center, Dong Wha Pharmaceutical Industry Co., Ltd (Anyang City, Korea). We previously reported that DW286, a novel fluoronaphthyridone antibiotic developed by Dong Wha Pharmaceutical Industry Co., Ltd, exhibited potent in vitro antibacterial activity against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and quinolone-resistant S. aureus (QRSA), and the most potent efficacy in experimental systemic mouse models of MRSA and QRSA infections.5 However, DW286 showed some side effects including genetic toxicity (data not shown).
Another novel fluoroquinolone antibiotic synthesized by the R&D Center, Dong Wha Pharmaceutical Industry Co., Ltd is DW-224a with the formula of 1-cyclopropyl-6-fluoro-7-[8-(methoxyimino)-2,6-diazaspiro[3,4]oct-6yl]-4-oxo-1,4-dihydro[1,8]naphthyridine-3-carboxylic acid hydrochloric acid salt (Figure 1). In the present study, we investigated the in vitro activity of DW-224a against various clinical isolates in comparison with DW286, ciprofloxacin and trovafloxacin. In addition, the in vivo protective efficacy of DW-224a against systemic infections caused by S. aureus, Streptococcus pyogenes, Streptococcus pneumoniae, Escherichia coli and Klebsiella pneumoniae was evaluated in mice.
|
|
Materials and methods |
|---|
|
TopAbstractIntroductionMaterials and methodsResults and discussionTransparency declarationsReferences |
|---|
Antimicrobial agents and bacteria
The studied compounds were obtained as follows: DW-224a, DW286 and ciprofloxacin were synthesized at the R&D Center, Dong Wha Pharmaceutical Industry Co., Ltd. Trovafloxacin was provided by Pfizer Pharmaceuticals (New York, NY, USA).
Clinical isolates were obtained from hospitals in Seoul, Korea, between 1996 and 2002. The challenge organisms used in the mouse systemic infections were as follows: S. pyogenes ATCC 8668 was obtained from the American Type Culture Collection (Rockville, MD, USA), and S. aureus Smith was kindly provided by Professor S. Goto of Toho University, Tokyo, Japan. E. coli MB4-78, K. pneumoniae MB4-02 and S. pneumoniae MB4-21 were selected through the pathogenicity screening of clinical isolates.6
Determination of MICs
Unless otherwise specified, MICs were determined by an agar dilution method with Mueller–Hinton agar (MHA; Difco Laboratories, Detroit, MI, USA) following the Clinical and Laboratory Standards Institute (formerly National Committee for Clinical Laboratory Standards) procedure.7 Enterococcus faecalis, Enterococcus faecium and S. pyogenes were grown on brain heart infusion (BHI) agar and S. pneumoniae and Haemophilus influenzae were grown on BHI agar supplemented with 1% bactosupplement B (Difco) and 1% Isovitalex (Difco) at 37°C. Test compounds were prepared according to the manufacturers' instructions and diluted in sterilized distilled water and further diluted in the corresponding medium to achieve a concentration range of 0.001–64 mg/L. Agar plates containing test compounds were inoculated with the strains using a microplater (Sakuma, Tokyo, Japan) that delivered 104 cfu per spot. The cultures were incubated at 37°C and the MIC determined after 18 h. MIC tests were performed in duplicate.
Determination of the in vivo activity
The study was designed to evaluate the protective effect of the fluoroquinolones in a systemic infection model in mice. The organisms used were S. aureus Smith, S. pyogenes ATCC 8668, S. pneumoniae MB4-21, E. coli MB4-78 and K. pneumoniae MB4-02. The organisms were cultured overnight in BHI broth at 37°C. Male ICR mice (body weight, 18–22 g; age, 4 weeks) were inoculated intraperitoneally with 0.3 mL of a bacterial suspension adjusted with 3% gastric mucin (ICN Biomedicals, Columbus, OH, USA) in saline solution at a dose 100 times higher than the minimal lethal dose. The challenge inoculum was sufficient to kill 100% of the untreated control mice, which died within 48 h after infection. An aliquot of 0.2 mL of each test compound was administered once orally to mice immediately after infection. Five groups of seven mice each were treated with 0.16, 0.63, 2.5, 10 or 40 mg/kg of each antibacterial agent. The 50% protective dose (PD50) was calculated by the method of Reed and Muench8 from the survival rates on day 7 after infection. All animal experiments were performed in accordance with the guidelines of our Institutional Animal Care and Use Committee.
|
Results and discussion |
|---|
|
TopAbstractIntroductionMaterials and methodsResults and discussionTransparency declarationsReferences |
|---|
In vitro activity
The antibacterial activity of DW-224a against clinical isolates was compared with those of DW286, ciprofloxacin and trovafloxacin (Table 1). The MIC values of the control compounds are comparable to previous results.5 Antibacterial activity of DW-224a was superior to the activities of ciprofloxacin and trovafloxacin and was slightly inferior to that of DW286 against QRSA and S. pyogenes. DW-224a was also more active than ciprofloxacin, similar to trovafloxacin and inferior to DW286 against QSSA and Staphylococcus epidermidis. Like DW286, DW-224a was more active than ciprofloxacin and comparable to trovafloxacin against E. faecalis and 3-fold more active than ciprofloxacin or trovafloxacin against E. faecium. Against S. pneumoniae, DW286 was most active and DW-224a was more active than ciprofloxacin and similar to trovafloxacin. In general, DW-224a showed potent activity against Gram-positive organisms. Against Gram-negative bacteria, including members of the family Enterobacteriaceae, DW-224a was inferior to ciprofloxacin, but it was as active as trovafloxacin or DW286. The MIC50s and MIC90s for clinical strains of E. coli, K. pneumoniae, Klebsiella oxytoca, Citrobacter freundii, Enterobacter cloacae, Enterobacter aerogenes, Proteus spp., Providencia stuartii, Morganella morganii, Serratia marcescens, Salmonella spp. and Shigella spp. were 0.031–1 and 0.125–8 mg/L, respectively. The activity of DW-224a against H. influenzae was superior to that of trovafloxacin and similar to the activities of ciprofloxacin and DW286. Against Pseudomonas aeruginosa, DW-224a was less active than ciprofloxacin or trovafloxacin and comparable to DW286. Against Stenatrophomonas maltophilia and Acinetobacter calcoaceticus, the activity of DW-224a was similar to the activities of the other compounds. In summary, in vitro activity of DW-224a against Gram-positive bacteria was higher than the activities of ciprofloxacin and trovafloxacin, but slightly lower than that of DW286. Especially against fluoroquinolone-resistant strains, such as QRSA, E. faecalis and E. faecium, the overall activities of DW-224a were more potent than those of ciprofloxacin and trovafloxacin. Against Gram-negative bacteria, DW-224a showed activity similar to the activities of trovafloxacin and DW286 and less activity than that of ciprofloxacin. These findings suggest that DW-224a, with increased activities against Gram-positive cocci and fluoroquinolone-resistant strains, yet retaining activity against Gram-negative species, may be very useful for the treatment of clinically significant pathogens, including multidrug-resistant Gram-positive pathogens.
|
In vivo activity
The therapeutic effects of DW-224a and comparative quinolones against systemic infections in mice are shown in Table 2. Against S. aureus Smith and S. pneumoniae MB4-21, the in vivo activity of DW-224a was inferior to that of DW286 and comparable to that of trovafloxacin, but considerably better than that of ciprofloxacin. Like DW286, DW-224a showed highest activity against infections with S. pyogenes ATCC 8668, with a PD50 of 0.26 mg/kg. In infections caused by E. coli MB4-78 and K. pneumoniae MB4-02, the activity of DW-224a was inferior to the activities of ciprofloxacin and trovafloxacin, but similar to that of DW286. In summary, DW-224a showed great in vivo efficacies against Gram-positive organisms, but similar or somewhat inferior activity to those of comparative compounds against Gram-negative bacteria. These results correlated with the in vitro MICs. Based on its in vitro and in vivo efficacy, DW-224a seems to be a promising antibiotic with a broad spectrum of antimicrobial activity, including potent activity against S. pneumoniae and S. pyogenes.
|
Safety pharmacology study of DW-224a was conducted after oral administration of the drug to mice, rats and dogs.9 DW-224a appears to have exerted no adverse effects on the central nervous, cardiovascular and respiratory systems with the exception of the effect on the QT interval prolongation. After oral administration of the drug to dogs, the absorption of DW-224a was fast;10 the plasma concentration of DW-224a was detected from the first blood sampling time (0.5 h) and reached its peak within 1–3 h. DW-224a was not accumulated above the toxic dose after the 4 week oral administration.10 Efficacy and safety or tolerability profile is now being assessed further in Phase I clinical trials to treat various bacterial infections.
|
Transparency declarations |
|---|
|
TopAbstractIntroductionMaterials and methodsResults and discussionTransparency declarationsReferences |
|---|
None to declare.
|
Acknowledgements |
|---|
This work was supported by the Second Stage of BK21 Research Division for Applied Pharmaceutical Life Sciences and by a grant of the Korea Health 21 R&D Project, Ministry of Health & Welfare, Republic of Korea (01-PJ1-PG4-01PT01-0013). We are grateful to Pfizer Pharmaceuticals for supplying trovafloxacin.
|
References |
|---|
|
TopAbstractIntroductionMaterials and methodsResults and discussionTransparency declarationsReferences |
|---|
1 Appelbaum PC and Hunter PA. (2000) The fluoroquinolone antibacterials: past, present and future perspectives. Int J Antimicrob Agents 16:5–15.[CrossRef][Web of Science][Medline]
2 Hendershot EF. (1995) Fluoroquinolones. Infect Dis Clin North Am 9:715–30.[Web of Science][Medline]
3
Garcia-Garrote F, Cercenado E, Martin-Pedroviejo J, et al. (2001) Comparative in vitro activity of the new quinolone gemifloxacin (SB-265805) with other fluoroquinolones against respiratory tract pathogens. J Antimicrob Chemother 47:681–4.
4
Klepser ME, Ernst EJ, Petzold CR, et al. (2001) Comparative bactericidal activities of ciprofloxacin, clinafloxacin, grepafloxacin, levofloxacin, moxifloxacin, and trovafloxacin against Streptococcus pneumoniae in a dynamic in vitro model. Antimicrob Agents Chemother 45:673–8.
5
Yun HJ, Min YH, Lim JA, et al. (2002) In vitro and in vivo antibacterial activities of DW286, a new fluoronaphthyridone antibiotic. Antimicrob Agents Chemother 46:3071–4.
6 Cleeland R and Squires E. (1991) Evaluation of new antimicrobials in vitro and in experimental animal infections. In Lorian V (Ed.). Antibiotics in Laboratory Medicine (Williams & Wilkins, Baltimore, MD) pp. 739–86.
7 National Committee for Clinical Laboratory Standards. (1990) Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria that Grow Aerobically—Second Edition: Approved Standard M7-A2 (NCCLS, Villanova, PA, USA).
8 Reed LJ and Muench H. (1938) A simple method of estimating fifty percent endpoints. Am J Hyg 27:493–7.
9 Kim EJ, Shin WH, Kim KS, et al. (2004) Safety pharmacology of DW-224a, a novel fluoroquinolone antibiotic agent. Drug Chem Toxicol 27:295–307.[CrossRef][Web of Science][Medline]
10 Han J, Kim JC, Chung MK, et al. (2003) Subacute toxicity and toxicokinetics of a new antibiotic, DW-224a, after single and 4-week repeated oral administration in dogs. Biol Pharm Bull 26:832–9.[CrossRef][Web of Science][Medline]
CiteULike 
Connotea 
Del.icio.us What's this?
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||