In vitro and in vivo activity of NY-198, a new difluorinated quinolone

Treatment of Acute Bacterial Conjunctivitis with Topical Lomefloxacin 0.3% Compared to Topical Ofloxacin 0.3%

Purpose

The main purpose of this prospective study was to compare the efficacy, local tolerance, and safety of topical lomefloxacin 0.3% and topical ofloxacin 0.3% in the treatment of acute bacterial conjunctivitis.

Patients and Methods

Forty patients with acute bacterial conjunctivitis were included in a randomized, prospective, parallel-group study. Twenty patients were assigned to the lomefloxacin group (Okacin®, CIBA Vision Ophthalmics) and 20 patients to ofloxacin (Oflox®, Allergan). Lomefloxacin 0.3% was given 1 drop every 2 hours during waking hours on the first day then twice daily for one week. Ofloxacin 0.3% eyedrops were given four times daily. All patients underwent eye examination and clinical findings were graded and recorded according to severity of lid hyperemia, lid edema, lid crusting, conjunctival edema and discharge, bulbar conjunctival hyperemia, palpebral conjunctival hyperemia, corneal edema, and ocular discomfort. The score for each clinical sign was recorded before and after treatment. The mean cumulative sum score (CSS) was obtained by adding the scores for signs and symptoms. All conjunctival swabs were cultured and tested for sensitivity. Patients with confirmed bacterial conjunctivitis were included.

Results

There were 10 male and 10 female patients in each group. The age range was from 1 to 78 years, and the mean age was 35 years in the lomefloxacin group. In the ofloxacin group the age range was from 1 to 70 years, and the mean age was 26 years. There was no significant difference between the two groups in relation to age or sex. The causative organisms were Staphylococcus epidermidis in 16 cases (36%), α-hemolytic Streptococci in 9 (20%), Haemophilus spp. 6 (13%), Staphylococcus aureus 5 (11%), Streptococcus pneumoniae 4 (9%), Pseudomonas aeruginosa 3 (7%), and other 2 (4%). The mean CSS for conjunctivitis was 12.1 before therapy in the lomefloxacin group and 12.7 in the ofloxacin group. On the 7th day of therapy, the mean CSS was 0.7 in the lomefloxacin group, and 1.6 for ofloxacin. All patients showed improvement, but a total of 18 out of 20 (88%) in the lomefloxacin group showed complete resolution compared to 15 (75%) in the ofloxacin group. The difference was not statistically significant (p = 0.08). Tolerance was excellent in both groups, and no side effects were reported. A burning sensation was noted by two patients, one in each group.

Conclusions

Lomefloxacin and ofloxacin were equally effective and safe in the treatment of acute bacterial conjunctivitis.

Efficacy and safety of lomefloxacin on bacterial extraocular disease in the horse

Lomefloxacin is a broad-spectrum fluoroquinolone antibiotic used for the treatment of bacterial extraocular disease. This study investigated the efficacy and safety of lomefloxacin eye drops for bacterial extraocular disease in horses. Lomefloxacin ophthalmic solution (0.3%) was instilled three times daily for 2–5 days in 65 horses diagnosed with bacterial extraocular disease based on clinical findings. Clinical observations and bacteriological examinations were performed at the start of treatment, 2 and 5 days after the start of treatment, and at the discontinuation or termination of treatment. Of the 65 horses, 64 were positive for bacteria, and 22 bacterial genera and 47 bacterial species were identified. The efficacy of lomefloxacin was evaluated in 63 horses; one horse with a negative culture and another with suspected bacterial contamination were excluded. Lomefloxacin was considered to be clinically effective in 54 horses. The major bacterial species identified were Staphylococcus aureus, Streptococcus equi subsp. zooepidemicus, Acinetobacter lwoffii, Staphylococcus xylosus, Staphylococcus vitulinus, Enterobacter agglomerans, Flavimonas oryzihabitans and Staphylococcus sciuri, with a cumulative disappearance rate of 80% or more at the termination of instillation. Excluding one horse that did not undergo a bacteriological examination, the remaining 62 horses were assessed for bacteriological outcome. Full or partial bacterial clearance was detected in 95% or more of the 62 horses. One of the 65 horses reported adverse events that had no causal relation with the eye drops. Our results showed that lomefloxacin is safe and effective for the treatment of bacterial extraocular disease in horses.

Topical Lomefloxacin versus Topical Chloramphenicol in the Treatment of Acute Bacterial Conjunctivitis

We performed a prospective, randomised, investigator-masked and parallel-group study to compare topical lomefloxacin 0.3% instilled twice daily with topical chloramphenicol instilled five times daily in the treatment of acute bacterial conjunctivitis. 191 patients (lomefloxacin 96, chloramphenicol 95) were enrolled in this study with clinically diagnosed acute bacterial conjunctivitis. The two treatment groups were similar at baseline. The treatments were equally effective and significantly (p < 0.001) reduced the Cumulative Sum Score of the clinical signs and symptoms of bacterial conjunctivitis. At the end of the trial, there was no difference between the two treatments in the Cumulative Sum Score of signs and symptoms (p = 0.63), and the investigator (p = 0.28) and patients' (p = 0.50) assessments of the success of therapy. The two drugs were equally well tolerated locally, with no serious systemic or local adverse drug reactions reported in any study patient. Bacteriological confirmation of acute conjunctivitis was possible in 96 patients (lomefloxacin 47, chloramphenicol 49) out of the 191 enrolled. Both treatments significantly (p < 0.001) reduced the conjunctival bacterial colony count score with no difference (p = 0.12) between the two treatment groups. In conclusion, lomefloxacin 0.3% eye drops instilled twice daily were as effective and well tolerated as chloramphenicol 0.5% eye drops instilled 5 times daily in the treatment of acute bacterial conjunctivitis.

Lomefloxacin versus trimethoprim/sulfamethoxazole in the treatment of adults with acute bacterial diarrhea

This study compared the efficacy and safety of lomefloxacin with that of trimethoprim/sulfamethoxazole (TMP/SMX) in the treatment of adult patients with acute diarrhea of bacterial etiology. Two centers enrolled a total of 133 patients; 99 (74%) presented with severe symptoms. The patients were randomized to receive either lomefloxacin 400 mg once daily (n=68) or TMP/SMX 160/800 mg twice daily (n=65) for five days. Bacteriologic success was achieved in 89.5% of evaluation lomefloxacin-treated patients and in 97.5% of patients treated with TMP/SMX. Clinical success was achieved in 100% and 97.5% of patients in the two treatment groups, respectively. The predominant organisms isolated in both groups at baseline, i.e. Shigella flexneri, Vibrio parahaemolyticus, and Salmonella Group D, were eradicated in all patients. Campylobacter jejuni was isolated at baseline in four patients in the lomefloxacin group but in none randomized to receive TMP/SMX; this organism persisted in three patients. Adverse events were experienced by 14 (23%) of the lomefloxacin-treated patients and by 18 (30%) of the TMP/SMX-treated patients. All adverse events reported were mild or moderate in severity and their distribution was similar in both groups. The results of this study show that lomefloxacin 400 mg once daily is as effective as TMP/SMX 160/800 mg twice daily and suggest that lomefloxacin is a promising new quinolone for the treatment of bacterial diarrhea.

Quinolones in 2005: an update

Quinolones are one of the largest classes of antimicrobial agents used worldwide. This review considers the quinolones that are available currently and used widely in Europe (norfoxacin, ciprofloxacin, ofloxacin, levofloxacin and moxifloxacin) within their historical perspective, while trying to position them in the context of recent and possible future advances based on an understanding of: (1) their chemical structures and how these impact on activity and toxicity; (2) resistance mechanisms (mutations in target genes, efflux pumps); (3) their pharmacodynamic properties (AUC/MIC and Cmax/MIC ratios; mutant prevention concentration and mutant selection window); and (4) epidemiological considerations (risk of emergence of resistance, clonal spread). Their main indications are examined in relation to their advantages and drawbacks. Overall, it is concluded that these important agents should be used in an educated fashion, based on a careful balance between their ease of use and efficacy vs. the risk of emerging resistance and toxicity. However, there is now substantial evidence to support use of the most potent drug at the appropriate dose whenever this is required.

Penetration of topically administered ofloxacin and trimethoprim into aqueous humor

Ocular penetration of two topical antibiotics used to treat bacterial conjunctivitis was assessed in adult volunteers scheduled for cataract surgery. In this randomized, parallel-group study, patients instilled trimethoprim sulfate 0.1%/polymyxin B (n = 23) or ofloxacin 0.3% (n = 25) QID for 3 days, plus 4 instillations in the hour before surgery. Analysis of aqueous humor samples obtained during surgery showed a 2.4-fold greater concentration of ofloxacin over trimethoprim (1.135 micro g/ml vs 0.470 micro g/ml; P <.0001). The greater concentration of ofloxacin in ocular tissue coupled with its superior antibacterial activity profile supports its use as an alternative to trimethoprim/polymyxin B for treatment of bacterial conjunctivitis.

Bioequivalence evaluation of lomefloxacin 400 mg tablets (Lomax versus Maxaquin in healthy human volunteers

This study represents the results of a randomized, single dose, two-treatment, two-period crossover study in 18 healthy male volunteers to assess the bioequivalence of two tablets of 400 mg lomefloxacin. The two formulations were: Lomax(R) (Julphar, United Arab Emirates) as the test formulation and Maxaquin(R) (Searle, S.A., UK) as the reference formulation. The study was conducted at the College of Pharmacy, King Saud University, Riyadh, Saudi Arabia, jointly with King Khalid University Hospital, Riyadh, Saudi Arabia. After overnight fasting the two products were administered as a single dose on two treatment days separated by a 1 week washout period. Serial blood samples were collected thereafter, for a period of 48 h. Plasma harvested from blood was analysed for lomefloxacin by a sensitive, reproducible and accurate HPLC method. Various pharmacokinetic parameters including AUC(0-t), AUC(0-infinity), C(max,) T(max), T(1/2), K(elm) and C(max)/AUC(0-infinity) were determined from plasma concentrations for both formulations and found to be in good agreement with reported values. Statistical modules applied to AUC(0-t), AUC(0-infinity) and C(max) revealed no significant difference in the two tested products. Based on these statistical inferences it was concluded that Lomax(R) is bioequivalent to Maxaquin(R).

Analysis of fluoroquinolones in biological fluids by high-performance liquid chromatography

High-performance liquid chromatographic methods for the analysis of fluoroquinolones in biological fluids are reviewed. In particular, sample preparation and handling procedures, chromatographic conditions, and detection methods are discussed. A summary of published high-performance liquid chromatographic assays for individual fluoroquinolones is included.

In vivo activity of HSR-903, a new fluoroquinolone, against respiratory pathogens

The in vivo activity of HSR-903, a new fluoroquinolone, against major bacteria which cause respiratory tract infections was evaluated. HSR-903 was active against experimental respiratory tract infections in mice challenged with penicillin-susceptible and penicillin-resistant Streptococcus pneumoniae and Haemophilus influenzae strains. Treatment with HSR-903 reduced the bacterial numbers in infected murine lungs. In accord with the pulmonary clearance results, the rates of survival for mice treated with HSR-903, sparfloxacin, levofloxacin, ciprofloxacin, and benzylpenicillin were 50, 30, 10, 0, and 0%, respectively, 14 days after being infected with penicillin-resistant S. pneumoniae. A pharmacokinetic study with pneumonic mice showed that the levels of HSR-903 in the lungs were seven to eight times higher than those in the plasma. These results indicate that clinical studies of HSR-903 against respiratory tract infections may be warranted.

In vitro activity of HSR-903, a new quinolone

The in vitro activity of the new fluoroquinolone HSR-903 was compared with those of ciprofloxacin, lomefloxacin, sparfloxacin, and levofloxacin. HSR-903 inhibited 90% of methicillin-susceptible and -resistant Staphylococcus aureus (MRSA) clinical isolates at 0.78 and 1.56 microg/ml, respectively, and its activity against MRSA was 16-fold higher than those of sparfloxacin and levofloxacin and 64-fold higher than that of ciprofloxacin. The MICs at which 90% of the isolates are inhibited (MIC90s) of HSR-903 for Streptococcus pyogenes and penicillin G-susceptible and -resistant Streptococcus pneumoniae (PRSP) were 0.10, 0.05, and 0.05 microg/ml, respectively. Against PRSP, the activity of HSR-903 was 4-fold higher than that of sparfloxacin and 32- to 256-fold higher than those of the other quinolones. The MIC90 of HSR-903 for Enterococcus faecalis was 0.20 microg/ml, and HSR-903 was more active than the other quinolones against enterococci. The activity of HSR-903 against members of the family Enterobacteriaceae and Pseudomonas aeruginosa was roughly similar to that of ciprofloxacin and greater than those of the other quinolones. Against Haemophilus influenzae, Moraxella catarrhalis, and Helicobacter pylori, HSR-903 was the most potent of the quinolones tested. The activity of HSR-903 was not affected by the medium, the inoculum size, or the addition of serum, but decreased under acidic conditions, as did those of the other quinolones tested. HSR-903 exhibited rapid bactericidal action and had a good postantibiotic effect on S. aureus and P. aeruginosa. HSR-903 inhibited supercoiling by DNA gyrase from Escherichia coli, but it was much less active against human topoisomerase II.

E-4695, a new C-7 azetidinyl fluoronaphthyridine with enhanced activity against gram-positive and anaerobic pathogens

E-4695, (-)-7-[3-(R)-amino-2-(S)-methyl-1-azetidinyl]-1-cyclopropyl-1,4- dihydro-6-fluoro-4-oxo-1,8-naphthyridine-3-carboxylic acid, is a new fluorinated naphthyridine with an azetidine moiety. The MICs of E-4695 at which 90% of the isolates were inhibited (MIC90s) were 0.06 to 0.5 microgram/ml for gram-positive cocci, including species of the genera Staphylococcus, Streptococcus, and Enterococcus, and the MIC90s against gram-negative pathogens such as members of the family Enterobacteriaceae (with the exception of Providencia spp. [MIC90, 8 micrograms/ml]) and Pseudomonas aeruginosa were 0.015 to 0.5 microgram/ml. E-4695 inhibited 90% of the Clostridium perfringens and Bacteroides fragilis isolates at 0.25 and 4 micrograms/ml, respectively. Against gram-positive cocci the potency of E-4695 was 2- to 8-fold higher than that of ciprofloxacin, 4- to 8-fold higher than that of ofloxacin, and 8- to 16-fold higher than that of fleroxacin. Against enteric bacteria and P. aeruginosa the potency of E-4695 was, in general, similar to that of ciprofloxacin and eightfold higher than those of ofloxacin and fleroxacin. E-4695 was four- and eightfold more potent than ciprofloxacin against C. perfringens and B. fragilis isolates, respectively. E-4695 and ciprofloxacin showed similar properties when the effects of pH or magnesium concentration were tested on them. E-4695 and ciprofloxacin had substantial reductions of activity only when pH decreased below 4.8. E-4695 and ciprofloxacin activities were not markedly affected by the presence of 5 or 10 mM Mg2+. The presence of serum and human urine at pH 7.2 decreased the activity of E-4695 between two- and fourfold. After an oral dose of 50 mg/kg of body weight, the maximum level in serum, the biological half-life, and the area under the concentration-time curve from 0 to 10 h for E-4695 were 13.2 microgram/ml, 3.3 h, and 45.6 microgram . h/ml, respectively. The area under the concentration-time curve from 0 to 4 h for ciprofloxacin was 2.3 microgram . h/ml at the same dose. Fifty-percent effective doses (ED50S) against Staphylococcus aureus HS-93 infections in mice were 4.5 mg/kg with E-4695 and 37.6 mg/kg with ciprofloxacin. Infection with Streptococcus pneumoniae 29206 was more effectively treated with E-4695 (ED50, 41,2 mg/kg) than with ciprofloxacin (ED50, 200 mg/kg). The ED50 of E-4695 for infections with Streptococcus pneumoniae 1625 was 132.2 mg/kg; ciprofloxacin was ineffective at 400 mg/kg against this strain. E-4695 was also more potent than ciprofloxacin in treatment of infections caused by gram-negative organisms such as Escherichia coli HM-42 (ED50S, 1.0 and 3.9 mg/kg, respectively). The ED50S of E-4695 and ciprofloxacin were 33.0 and 145.5 mg/kg against P. aeruginosa HS-116 and 9.6 and 18.9 mg/kg against P. aeruginosa B-120, respectively. The therapeutic efficacy of E-4695 may depend not only on its in vitro activity but also on its improved pharmacokinetic properties.

In vitro antibacterial activity of AM-1155, a novel 6-fluoro-8-methoxy quinolone

The in vitro antibacterial activity of AM-1155 against a wide variety of clinical isolates was compared with those of other fluoroquinolones. The MICs of AM-1155 for 90% of Staphylococcus aureus, Streptococcus pneumoniae, and Enterococcus faecalis isolates tested were 0.10, 0.39, and 0.78 microgram/ml, respectively. The antibacterial activity of AM-1155 against gram-positive bacteria and anaerobes was comparable to those of sparfloxacin and tosufloxacin. AM-1155 inhibited 90% of most species of the family Enterobacteriaceae at a concentration of 0.39 microgram/ml. AM-1155 generally had activity comparable to that of sparfloxacin against gram-negative bacteria. AM-1155 showed moderate activity against methicillin- and quinolone-resistant S. aureus. AM-1155 demonstrated bactericidal activity at the MIC. The frequency of occurrence of spontaneous mutants resistant to four times the MIC of AM-1155 was < 1 x 10(9) for S. aureus, Escherichia coli, and Pseudomonas aeruginosa. AM-1155 strongly inhibited the supercoiling activities of DNA gyrases purified from E. coli and S. aureus.

Determination of lomefloxacin in human plasma by solid-phase extraction and high-performance liquid chromatography with UV detection

A high-performance liquid chromatographic method for the determination of lomefloxacin in human plasma has been developed and validated. A solid-phase extraction procedure was used to isolate lomefloxacin from the biological matrix prior to the quantitative analysis. The compound was separated on a Vydac anion-exchange column using acetonitrile-phosphate buffer (pH 7.0) as the mobile phase and quantified by measuring its UV absorbance at 280 nm. The lower limit of detection for the analyte was 0.05 micrograms ml-1. Enoxacin was used as the internal standard. The calibration graph of the method was linear from 0.1 to 10 micrograms ml-1 of lomefloxacin in human plasma. This procedure is suitable for pharmacological and pharmacokinetic studies of lomefloxacin.

Application of topical lomefloxacin against experimental Pseudomonas endophthalmitis in rabbits

Lomefloxacin is a new quinolone compound with a broad antibacterial spectrum and excellent penetration into the aqueous humor by topical application. Therefore, an experimental study was done to evaluate the efficacy of topical lomefloxacin against experimental endophthalmitis with Pseudomonas aeruginosa. Lomefloxacin eye drops were instilled six times a day onto infected rabbit eyes and gentamicin, sulbenicillin and saline were also tested comparatively in the same manner as lomefloxacin. Clinical observation for 1 week and counting viable pseudomonas cell numbers in the anterior chamber were done. Among all topical eye drops tested, lomefloxacin was shown to be most effective in lowering clinical scores and viable cell numbers in the anterior chamber. In conclusion, lomefloxacin is expected to be a useful ophthalmic solution in the treatment of pseudomonal endophthalmitis.

Lomefloxacin clinical pharmacokinetics

Lomefloxacin is a quinolone antibiotic with chemical and microbiological properties similar to most commercially available agents of this class. There are differences, however, between lomefloxacin and other quinolones in activity against specific micro-organisms, a situation that is typical of most antibiotic classes. The pharmacokinetics of lomefloxacin support once- or twice-daily dosage, depending on the pathogen or site of infection. This is a result of its relatively high serum concentrations and long half-life. The outstanding pharmacokinetic features of lomefloxacin are its high degree of tissue distribution, lack of significant metabolism (and, therefore, no competitive drug interactions with other metabolised drugs showing a common metabolic pathway), and good oral absorption. Like most fluoroquinolones, lomefloxacin can chelate with heavy metals. However, this interaction can be eliminated by administering lomefloxacin 2h before the cation-containing products. Dosage adjustments are required in patients with renal dysfunction. However, patients with liver disease do not require alterations in lomefloxacin dosage regimens. The safety profile, lack of significant drug interactions and convenience of administration make lomefloxacin a useful agent in specific clinical settings.

In vitro and in vivo antibacterial activities of E-4868, a new fluoroquinolone with a 7-azetidin ring substituent

E-4868, (-)-7-[3-(R)-amino-2-(S)-methyl-1-azetidinyl]-1-(2,4- difluorophenyl)-1,4-dihydro-6-fluoro-4-oxo-3-quinolinecarboxylic acid, is a new fluoroquinolone with an azetidine moiety at the 7 position. The in vitro activity of E-4868 has been compared with those of ciprofloxacin, ofloxacin, and fleroxacin, while the activity of ciprofloxacin was used as reference for in vivo studies. The MICs of E-4868 for 90% of the isolates tested (MIC90s) were 0.06 to 0.5 microgram/ml against gram-positive organisms, including Staphylococcus, Streptococcus, and Enterococcus spp. In general, the in vitro potency of E-4868 against gram-positive bacteria was higher than those of all of the other fluoroquinolones tested. MIC90s against members of the family Enterobacteriaceae between 0.03 and 1 microgram/ml were observed, with the exception of those against Serratia marcescens and Providencia spp., and a MIC90 of 2 micrograms/ml against Pseudomonas aeruginosa was obtained. E-4868 inhibited 90% of the Clostridium spp. and Bacteroides spp. at 2 micrograms/ml and was twofold more active than ciprofloxacin. An increase in the Mg2+ concentration from 1 to 10 mM increased the MIC between two and three times. Human urine caused a significant decrease in activity of E-4868, which was more pronounced at pH 5.5 than at pH 7.2. The presence of serum also decreased the activity of E-4868. Fifty percent effective dose (ED50) values against experimental Escherichia coli HM-42 infections in mice were 3.9 mg/kg of body weight with E-4868 and 3.5 mg/kg of body weight with ciprofloxacin. Corresponding ED50 values against P. aeruginosa HS-116 were 93.2 and 107.8 mg/kg, respectively, and those against Staphylococcus aureus HS-93 were 6.5 and 44.6 mg/kg, respectively. In experimental infections with Streptococcus pneumoniae 84551, the ED50 value of E-4868 was 154.4 mg/kg, while ciprofloxacin proved totally inactive at a dose of 400 mg/kg. When E-4868 was administered orally at a dose of 50 mg/kg in mice, the area under the concentration-time curve (0 to 4 h) value was 28.4 microgram . h/ml, while an area under the concentration-time curve value of 2.3 microgram . h/ml was observed for ciprofloxacin at the same dose. In these studies, levels of the two agents in blood 1 h postadministration were 7.6 and 1.2 microgram/ml, respectively.

In vitro activity of E-4868, a new trifluoroquinolone, compared to six similar compounds

The compound E-4868 (Laboratorios Dr. Esteve) is a trifluoro, 7-azetidinyl quinolone with properties resembling those of other fluoroquinolones. Its activity in vitro was compared to that of six other similar drugs against more than 700 nosocomial isolates using standard methods. The MIC50s of E-4868 for enteric bacilli ranged from 0.015 to 0.25 micrograms/ml, being highest for Providencia spp. Pseudomonas aeruginosa strains were two-fold more susceptible to E-4868 than to ofloxacin. MICs of E-4868 for Haemophilus influenzae, Moraxella catarrhalis and pathogenic Neisseria spp. were all < or = 0.12 micrograms/ml. E-4868 was equal in activity to or eight-fold more active than ciprofloxacin against gram-positive cocci. The MICs of E-4868 for pneumococci were all < or = 0.5 micrograms/ml but anaerobes such as Bacteroides fragilis were generally less susceptible (MIC90, 4 micrograms/ml). There was almost complete cross-resistance to several other fluoroquinolones. Resistant mutants were selected by a multiple passage technique but the rate of mutation to resistance was very low (< 10(-8)) at an 8 x MIC.

Comparative study of penetration of lomefloxacin and ceftriaxone into transudative and exudative pleural effusion

We investigated the transpleural penetration of lomefloxacin (LFLX) and ceftriaxone (CTRX). LFLX (200 mg) was administered orally to three patients with transudative fluid and four with exudative fluid, and 2 g of CTRX was administered by drip infusion to four patients with transudative fluid and three with exudative fluid. For both groups that received LFLX and CTRX, blood samples were drawn at time zero and 1, 2, and 6 h after drug administration. Thoracocentesis of each group was performed at 6 h after drug administration. The mean ratios of concentrations in pleural fluid/maximum concentrations in serum (P/S max) of LFLX were 66% in patients with transudative fluid and 69% in patients with exudative fluid. The mean ratios of P/S max of CTRX were 9.1% in patients with transudative fluid and 13.5% in patients with exudative fluid. The P/S max ratios for the penetration of LFLX were five to six times higher than those for CTRX. In addition, there was less differentiation in concentrations of LFLX in pleural fluid between the transudative and exudative effusions than there was in the concentrations of CTRX.

In vitro antibacterial activity of Q-35, a new fluoroquinolone

The in vitro activity of Q-35, an 8-methoxy fluoroquinolone, was compared with those of ofloxacin, ciprofloxacin, tosufloxacin, lomefloxacin, and sparfloxacin. The MICs of Q-35 for 90% of strains tested (MIC90s) of Staphylococcus aureus, methicillin-resistant S. aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, and Streptococcus pyogenes were 0.2, 6.25, 0.2, 0.39, and 0.39 micrograms/ml, respectively. The activity of Q-35 was 4- to 16-fold greater than those of ofloxacin, ciprofloxacin and lomefloxacin but equal to those of tosufloxacin and sparfloxacin against these organisms. For 82 ciprofloxacin-resistant staphylococci (MIC90 = 100 micrograms/ml), Q-35 was the most active of the new quinolones tested (MIC90 = 6.25 micrograms/ml). The MIC90s of Q-35 against Escherichia coli, Enterobacter aerogenes, and Pseudomonas aeruginosa were 0.2, 0.78, and 12.5 micrograms/ml, respectively, and Q-35 was 2- to 16-fold less active than the other quinolones tested. Q-35 showed potent bactericidal activity and inhibited the supercoiling activity of DNA gyrase of S. aureus, E. coli, and P. aeruginosa.

MIC and disk diffusion quality control guidelines for Neisseria gonorrhoeae susceptibility tests of cefdinir, cefetamet, CI-960, fleroxacin, lomefloxacin, and temafloxacin

Cefdinir (FK482), cefetamet (Ro 15-8074), CI-960, fleroxacin, lomefloxacin, and temafloxacin have potent activities against Neisseria gonorrhoeae. They were tested in a multilaboratory study to establish quality control guidelines. Quality control ranges for N. gonorrhoeae ATCC 49226 were determined by using multiple GC agar lots, three disk lots, and a number of test replicates consistent with the M23-T guidelines of the National Committee for Clinical Laboratory Standards. The MIC ranges included 2 to 4 log2 dilution steps. The recommended inhibition zone diameter ranges were generally 7 to 8 mm and included greater than or equal to 91.3% of all recorded study results.

Interpretive criteria for susceptibility testing of CI-960 (PD127391, AM-1091), fleroxacin, lomefloxacin, and temafloxacin against Neisseria gonorrhoeae, including drug stability in GC agar medium

CI-960, fleroxacin, lomefloxacin, and temafloxacin were tested against over 100 strains of Neisseria gonorrhoeae. Each organism was tested in triplicate by using agar dilution and disk diffusion methods recommended by the National Committee for Clinical Laboratory Standards. CI-960 was the most potent compound, with a MIC against 90% of the strains tested of 0.008 microgram/ml, and the least active was fleroxacin (MIC against 90% of strains, 0.12 microgram/ml). Only the susceptible interpretive category was recommended for the CI-960 tests as follows: 5-micrograms disk, greater than or equal to 39 mm (MIC correlate, less than or equal to 0.12 microgram/ml). Three interpretive categories were proposed for the other fluoroquinolones as follows: fleroxacin, 5-micrograms disk susceptible at greater than or equal to 33 mm (MIC correlate, less than or equal to 0.25 microgram/ml), intermediate at 28 to 32 mm (MIC correlate, 0.5 microgram/ml), and resistant at less than or equal to 27 mm (MIC correlate, greater than 0.5 microgram/ml); lomefloxacin, 10-micrograms disk susceptible at greater than or equal to 35 mm (MIC correlate, less than or equal to 0.12 microgram/ml), intermediate at 28 to 34 mm (MIC correlates, 0.25 to 0.5 microgram/ml), and resistant at less than or equal to 27 mm (MIC correlate, greater than 0.5 microgram/ml); and temafloxacin, 5-micrograms disk susceptible at greater than or equal to 36 mm (MIC correlate, less than or equal to 0.06 microgram/ml), intermediate at 28 to 35 mm (MIC correlates 0.12 to 0.25 microgram/ml), and resistant at less than or equal to 27 mm (greater than 0.25 microgram/ml). Interpretive agreement between disk diffusion results and the MICs was 100% for each agent, with the exception of lomefloxacin, which had a 0.9% minor error. All drugs were stable in GC agar medium for at least 21 days when stored at 2 to 5 degrees C.

Lomefloxacin versus amoxicillin in the treatment of acute exacerbations of chronic bronchitis: an Italian multicenter study

Nine centers in Italy participated in a worldwide, multicenter study comparing the effectiveness and safety of lomefloxacin and amoxicillin in patients with acute exacerbations of chronic bronchitis caused mainly by gram-negative pathogens. The 157 enrolled patients received either 400 mg lomefloxacin once daily (n = 78) or 500 mg amoxicillin every 8 hours (n = 79) for 7-10 days. A total of 131 patients were evaluable for bacteriologic efficacy and 154 for clinical efficacy. At 2-4 days after the conclusion of treatment, the bacterial eradication rate was 84.8% for lomefloxacin-treated patients and 64.6% for amoxicillin-treated patients (p = 0.0065); the clinical success rate (cure plus improvement) for lomefloxacin was 94.7% and for amoxicillin was 83.3% (p = 0.0212). The reinfection rate was lower in the lomefloxacin group than in the amoxicillin group (3.0% vs 13.8%, p = 0.0382). Both drug regimens were well tolerated. Once-a-day treatment with 400 mg lomefloxacin was more effective than 500 mg amoxicillin three times daily for the treatment of acute exacerbations of chronic bronchitis caused by gram-negative pathogens.

Fluoroquinolone (Lomefloxacin) International Surveillance Trial: a report of 30 months of monitoring in vitro activity

The antimicrobial activity and spectrum of lomefloxacin were assessed by standardized disk diffusion methods in 36 countries. More than 500,000 facultative organisms were tested during the first 30 months of a 3-year monitoring interval. Lomefloxacin demonstrated inhibition (zones greater than or equal to 19 mm) of greater than 90% of Enterobacteriaceae, greater than 99% of Moraxella (Branhamella) catarrhalis, greater than 98% of Haemophilus spp., and 91% of Staphylococcus aureus strains. Pseudomonas spp., especially Pseudomonas aeruginosa (18% resistance), were considered moderately susceptible, as were most strains of streptococci and enterococci. Some variation of national/regional fluoroquinolone resistance rates was observed, using lomefloxacin as an index or indicator drug, with the highest numbers of resistant strains being isolated in France. However, these data demonstrated a wide spectrum of lomefloxacin activity in all nations monitored.

Penetration of lomefloxacin into bronchial secretions following single and multiple oral administration

The bronchial penetration of lomefloxacin, a new difluorinated quinolone, was evaluated in 36 patients who underwent bronchoscopies for diagnostic purposes. Patients were randomized into two groups, with 18 patients (Group I) receiving a single oral dose of 400 mg lomefloxacin and 18 patients (Group II) receiving 400 mg twice daily. Samples of serum and bronchial secretions were collected simultaneously in both groups at 1, 2, or 4 hours after lomefloxacin administration. The results of this study showed that bronchial penetration of lomefloxacin was rapid and yielded high concentrations; the mean bronchial levels of the drug reached 2.78 +/- 3.64 micrograms/mL in Group I 1 hour after the dose, and 2.84 +/- 1.73 micrograms/mL in Group II at the fourth hour. The ratio between bronchial and simultaneous serum concentrations was 89% at the first and second hours after the dose for Group I, and it was 77% 4 hours after oral administration in Group II. In comparing these results to previous reports of lomefloxacin penetration into bronchial mucosa or of concentrations of other new fluoroquinolones into bronchial secretions, it is to be noted that the local concentrations of the newer quinolones are of very similar values, ranging from 2.7 micrograms/mL (ofloxacin) to 4.46 micrograms/mL (pefloxacin). This study confirms that lomefloxacin achieves high tissue concentrations in the respiratory tree; this characteristic, together with lomefloxacin's antibacterial spectrum, indicates promise in the treatment of many respiratory infections.

A double-blind study of two dosage regimens of lomefloxacin in bacteriologically proven exacerbations of chronic bronchitis of gram-negative etiology

Lomefloxacin has been shown to produce high and sustained concentrations in serum and bronchial mucosa after once-daily administration. This study was designed to assess whether a dose response exists for 400 mg lomefloxacin given once daily or twice daily for 10 days in the treatment of acute bacterial exacerbations of chronic bronchitis of gram-negative etiology. A total of 100 adult patients with acute exacerbations of chronic bronchitis were enrolled at 10 study sites in Germany. Patients with confirmed bacterial pathogens in the baseline sputum culture (once-daily group n = 49, twice-daily group n = 47) were eligible for analysis of bacteriologic and clinical efficacy. The eradication rates for the most frequently isolated baseline pathogens, Haemophilus influenzae, Pseudomonas aeruginosa, and Klebsiella pneumoniae, were at least 75% for both treatment regimens. Overall, once-daily treatment eradicated baseline pathogens in 42 of 49 (85.7%) patients, while twice-daily treatment eradicated pathogens in 43 of 47 (91.5%). This difference was not statistically significant (p = 0.226). Clinically, 47 of 49 (95.9%) patients in the once-daily group and 46 of 47 (97.9%) in the twice-daily group were cured or improved (p = 0.307). Both regimens were well tolerated; there were no differences in the incidence (six patients in each group), types, or severity of adverse events, nor was there clinical evidence of theophylline interaction. The results of this study demonstrate that once-daily treatment with 400 mg lomefloxacin is as effective as twice-daily dosing with 400 mg in patients with acute bacterial exacerbations of chronic bronchitis.

Lomefloxacin: microbiologic assessment and unique properties

In comparative studies, lomefloxacin, a new difluorinated quinolone, exhibits broad antibacterial activity in vitro, similar or superior to that of other quinolones (enoxacin, ofloxacin, pipemidic acid, nalidixic acid, and norfloxacin) but less than that of ciprofloxacin. Lomefloxacin inhibited Neisseria gonorrhoeae, Moraxella (Branhamella) catarrhalis, Haemophilus influenzae, Pseudomonas aeruginosa, Staphylococcus aureus, and the majority of aerobic gram-negative rods, including nosocomial isolates, at concentrations readily achievable in biologic fluids and tissues. Lomefloxacin was less active against obligate anaerobes and streptococci. Organisms resistant to methicillin, penicillin, or the aminoglycosides were susceptible to lomefloxacin. No significant lomefloxacin resistance was identified in 18 countries in which in vitro studies were conducted, with the exception of a small number of strains tested in France. The frequency with which spontaneous single-step resistance to lomefloxacin develops in vitro is low.

Comparison of the safety and efficacy of lomefloxacin and trimethoprim/sulfamethoxazole in the treatment of uncomplicated urinary tract infections: results from a multicenter study

Lomefloxacin, a new difluorinated quinolone, and trimethoprim/sulfamethoxazole (TMP/SMX) were compared in the treatment of adults with uncomplicated urinary tract infections. The study was conducted as a multicenter, controlled, prospectively randomized, single-blind study in five countries (Argentina, Belgium, Brazil, Mexico, and Venezuela). A total of 254 patients were enrolled: 129 in the lomefloxacin group and 125 in the TMP/SMX group. Patients received either 400 mg lomefloxacin orally once daily or 160 mg/800 mg TMP/SMX orally twice daily for 7-10 days. Escherichia coli and Proteus mirabilis were the pathogens most frequently isolated. At 5-9 days post-therapy, satisfactory bacteriologic results were noted in 98.4% of patients treated with lomefloxacin and in 95.8% of patients in the TMP/SMX group (p = 0.2153). Clinical success 5-9 days post-therapy was noted in 99.2% of patients in the lomefloxacin group and in 98.3% of patients in the TMP/SMX group (p = 0.5138). Adverse events probably related to treatment occurred in 6% of those treated with lomefloxacin and in 7% of patients treated with TMP/SMX. Once-daily oral lomefloxacin is a well-tolerated and effective treatment of uncomplicated urinary tract infections caused by susceptible pathogens.

The U.S. clinical experience with lomefloxacin, a new once-daily fluoroquinolone

Lomefloxacin is a new fluoroquinolone antimicrobial agent that has undergone extensive worldwide clinical evaluation. This report summarizes the safety and efficacy of lomefloxacin in the treatment of uncomplicated urinary tract infections, complicated urinary tract infections, acute exacerbations of chronic bronchitis, and for prophylaxis during urinary tract surgery. The clinical data presented are an overview of all clinical studies conducted in the United States to date. The results have been derived from multiple studies in which patients received lomefloxacin or a comparative agent in either blinded or open-label studies. During the course of the clinical program in the United States, lomefloxacin has been compared with oral norfloxacin, ciprofloxacin, and cefaclor, as well as parenteral cefotaxime. In all instances, the once-daily oral administration of lomefloxacin was either equally effective or statistically significantly superior in clinical and/or bacteriologic efficacy to these comparative agents. In addition, the comparators were administered either two or three times per day, except in the surgical prophylaxis studies, in which single doses of each antibiotic were administered preoperatively. These results attest to the value of the convenience and simplicity of the oral dosing regimen for lomefloxacin. During the course of the clinical program, lomefloxacin was well tolerated, with most adverse events of mild to moderate severity. In general, the incidence of adverse events for patients and subjects receiving lomefloxacin was comparable to that observed in patients treated with comparator drugs. The most common adverse events were related to the gastrointestinal tract (nausea and diarrhea), the skin and appendages (photosensitivity), and the central nervous system (dizziness and headache). A sub-analysis of adverse events in the respiratory studies demonstrated that concomitant administration of lomefloxacin and theophylline does not increase the incidence of adverse events when compared to lomefloxacin alone. An additional sub-analysis also showed that the incidence of adverse events in elderly patients was similar to that in younger patients. The results of the U.S. clinical program indicate that lomefloxacin administered orally once daily is effective and well tolerated in a variety of infections of bacterial origin.

Lomefloxacin concentrations in bone after a single oral dose

We studied the penetration characteristics of lomefloxacin in bone in 30 patients with osteoarthritis undergoing total hip replacement. Patients were given a single oral 400 mg dose at various times from 1 to 12 hours prior to removal of bone samples. The peak plasma and bone (subchondral bone from femoral head) concentrations reached approximately 4.0 micrograms/mL at 2 hours post-dose and 3.0 micrograms/mL at 3 hours post-dose, respectively. At 12 hours post-dose both plasma and bone concentrations were still greater than 1.0 microgram/mL. Two hours after dosing the average bone-to-plasma ratio was greater than 0.6. These data indicate that a single 400 mg oral dose of lomefloxacin attains bone concentrations that are above its usual minimum inhibitory concentrations for susceptible organisms.

Efficacy of lomefloxacin as compared to norfloxacin in the treatment of uncomplicated urinary tract infections in adults

The efficacy and safety of 7-10-day courses of lomefloxacin (single daily dose of 400 mg) or norfloxacin (twice-daily doses of 400 mg) for the treatment of uncomplicated urinary tract infections were compared in two large, multicenter, randomized trials. This article presents the combined results of these trials, which were conducted in a total of 27 centers throughout the United States. A total of 727 adults, mostly women, with symptoms of acute urinary tract infection were enrolled; 370 patients were randomized to lomefloxacin treatment, and 357 received norfloxacin. The bacteriologic cure rate at 5-9 days post-therapy was 98.2% in the lomefloxacin group and 96.3% in the norfloxacin group (p = nonsignificant). The clinical success rate of 99.1% in the lomefloxacin group was significantly higher than the success rate of 93.5% in the norfloxacin group (p = 0.002). Adverse events were reported by 157 lomefloxacin-treated patients and 129 patients receiving norfloxacin. Adverse events attributable to drug treatment occurred in 41 patients (11.1%) in the lomefloxacin group and 27 (7.6%) in the norfloxacin group. Eight lomefloxacin (2.2%) and three norfloxacin patients (0.8%) were withdrawn from treatment because of adverse events probably attributable to the drug. The incidence of dizziness, tremor, and photosensitivity rash was higher in the lomefloxacin group than in the norfloxacin group, while the incidence of nausea was higher in the norfloxacin group. The results of these trials demonstrate that once-daily administration of 400 mg lomefloxacin is as safe and effective clinically as, and superior bacteriologically to, twice-daily administration of 400 mg norfloxacin in the treatment of acute uncomplicated urinary tract infections in adult patients.

Penetration of lomefloxacin into human prostatic tissue

Serum and prostatic tissue concentrations of lomefloxacin were measured in 12 elderly patients who underwent transurethral resection of the prostate after receiving a single oral dose of 400 mg. The peak serum concentration of lomefloxacin was 2.5-10.0 micrograms/mL (mean, 5.2 +/- 1.9 micrograms/mL). During surgery, serum and tissue concentrations averaged 4.6 +/- 2.2 micrograms/mL and 6.5 +/- 2.7 micrograms/g, respectively. The ratio of tissue to serum concentrations was 1.53 +/- 0.54. The levels of lomefloxacin in serum and prostatic tissue were found to be higher than the minimum inhibitory concentration (MIC) values for most urinary tract pathogens.

Pharmacokinetics of lomefloxacin in patients with cirrhosis

The effect of liver failure on the pharmacokinetics of lomefloxacin was studied in 12 patients with cirrhosis. Patients received a single oral dose of 400 mg lomefloxacin, and blood and urine samples were collected at intervals over the next 48 hours. The concentrations of lomefloxacin in all samples were measured using high-pressure liquid chromatography (HPLC). The mean (+/- standard deviation) maximum plasma concentration (Cmax) in these patients was 3.9 +/- 1.20 micrograms/mL. The mean time to maximum serum concentration (Tmax) was 2.1 +/- 2.6 hours, and the mean elimination half-life (t1/2) was 9.16 +/- 1.93 hours. Mean renal clearance was 88.9 +/- 38.0 mL/min/1.73 m2, and the mean nonrenal clearance was 61.6 +/- 19.0 mL/min/1.73 m2, which corresponded to 41% of the total body clearance. No correlations were observed between nonrenal clearance and hepatic insufficiency (Pugh score) or nonrenal clearance and plasma bilirubin. These results show that liver failure does not per se affect lomefloxacin kinetics. Thus, no adjustments in lomefloxacin dosages appear to be necessary for patients with impaired liver function tests.

Urinary tract infection prophylaxis in transurethral surgery: oral lomefloxacin versus parenteral cefuroxime

The purpose of this study was to compare the efficacy and safety of single-dose oral lomefloxacin and single-dose parenteral cefuroxime for the prevention of urinary tract infection following transurethral surgery. A total of 63 patients were enrolled in this prospective, randomized open-label study, which was conducted at two medical centers in France. Patients were randomized to receive either 400 mg of oral lomefloxacin 2-6 hours before surgery or 1.5 g parenteral cefuroxime 30-90 minutes before surgery. Postoperative clinical evaluation was performed daily, and bacteriologic evaluation included urine cultures performed 24 hours after surgery, just before and 1 day after removal of the indwelling catheter, and 3-5 days after surgery. Another urine culture was optionally performed 1-3 months after surgery. Infection was defined as a urinary bacteria count greater than or equal to 10(5) colony-forming units (CFU)/mL of urine. Of the 63 patients enrolled, 54 were evaluable for efficacy, 27 in each group. The success rate of prophylaxis was 88.9% in the lomefloxacin group and 88.5% in the cefuroxime group (p = nonsignificant). None of the 16 lomefloxacin-treated patients who were re-cultured at 1-3 months was found to be infected. Adverse events were minor in both groups. A single oral dose of lomefloxacin was as efficacious and as safe as a single intravenous dose of cefuroxime for prevention of postoperative urinary tract infection in patients undergoing transurethral surgery.

Lomefloxacin. A review of its antibacterial activity, pharmacokinetic properties and therapeutic use

The antibacterial efficacy of oral lomefloxacin has been investigated in a wide variety of infections, including respiratory and uncomplicated and complicated urinary tract infections, obstetric, gynaecological, joint, skin, oral, ear, nose, throat and eye infections. It has also been used as an otic solution in patients with otitis media and as an ophthalmic solution in the treatment of eye infections. In clinical trials its efficacy is equivalent to that of other quinolones and it is at least as effective as other antibacterial drugs ordinarily used in these infections. Lomefloxacin offers certain advantages compared with other quinolone antibacterial drugs in that it may be conveniently administered once daily and theophylline dosage adjustment does not appear to be necessary in patients receiving this bronchodilator concomitantly. Thus, orally administered lomefloxacin should prove a useful broad spectrum antibacterial drug for a wide variety of clinical infections.