Levofloxacin: a therapeutic review

Identification of CH2-linker modified desfluoroquinolone-aminopyrimidine hybrids to combat antibiotic-resistant gram-positive bacteria

The increasing prevalence of antibiotic-resistant bacterial infections has emerged as a major public health crisis, necessitating an urgent need for the development of new antimicrobial agents. In this manuscript, structural modifications were conducted on the CH2 linker of the antibacterial desfluoroquinolone-aminopyrimidine hybrids that we had previously obtained, resulting in compounds A7, B1, and D6. These three compounds exhibited potent activity against a panel of antibiotic-resistant Gram-positive bacteria, including fluoroquinolone-resistant Staphylococcus aureus, linezolid-resistant Staphylococcus aureus, vancomycin-intermediate Staphylococcus aureus (VISA), and vancomycin-resistant Enterococcus faecium. Particularly, despite their structural similarity to classical quinolones, compounds A7, B1, and D6 exhibited no cross-resistance with ciprofloxacin. Additionally, the difluorinated CH2-linker modified compound demonstrated enhanced metabolic stability. These promising results encourage us to move forward to the next phase of structural optimization, with a specific focus on reducing mammalian cytotoxicity.

Antibacterial Mechanisms and Clinical Impact of Sitafloxacin

Sitafloxacin is a 4th generation fluoroquinolone antibiotic with broad activity against a wide range of Gram-negative and Gram-positive bacteria. It is approved in Japan and used to treat pneumonia and urinary tract infections (UTIs) as well as other upper and lower respiratory infections, genitourinary infections, oral infections and otitis media. Compared to other fluoroquinolones, sitafloxacin displays a low minimal inhibitory concentration (MIC) for many bacterial species but also activity against anaerobes, intracellular bacteria, and persisters. Furthermore, it has also shown strong activity against biofilms of P. aeruginosa and S. aureus in vitro, which was recently validated in vivo with murine models of S. aureus implant-associated bone infection. Although limited in scale at present, the published literature supports the further evaluation of sitafloxacin in implant-related infections and other biofilm-related infections. The aim of this review is to summarize the chemical-positioning-based mechanisms, activity, resistance profile, and future clinical potential of sitafloxacin.

Functionalization of MXene using iota-carrageenan, maleic anhydride, and N,N'-methylene bis-acrylamide for high-performance removal of thorium (IV), uranium (IV), sulfamethoxazole, and levofloxacin

An increasing quantity of pollutants has been discharged into the aquatic media, posing a serious hazard to public health. To address this issue, a new sorbent material, MXene@i.Carr@MaMb, was developed through the functionalization of the MXene surface using iota-carrageenan (i.Carr), maleic anhydride, and N, N'-methylene bis-acrylamide. This sorbent material was designed to remove thorium (Th (IV)) effectively, uranium (U (IV)), sulfamethoxazole (SMX), and levofloxacin (LEV) from wastewater. The MXene@i.Carr@MaMb composite incorporated significant functional groups, including OH, F, and O from MXene, oxygen and ester sulfate groups from iota-carrageenan (i.Carr), and OH, NH, and CO groups from N, N'-methylene bis-acrylamide, and maleic anhydride, which interacted with the UV (IV), Th (IV), SMX, and LEV pollutants through electrostatic interaction, complexation, and hydrogen bonding. MXene@i.Carr@MaMb composite exhibited excellent sorption capacities for Th (IV) (3.6 ± 0.03 mmol g-1), U (IV) (3.7 ± 0.09 mmol g-1), SMX (5.8 ± 0.03 mmol g-1), and LEV (5.9 ± 0.05 mmol g-1) at 323.15 K. The sorption kinetics and isotherms of radioactive metals and antibiotics can be well-described using pseudo-first-order kinetic models and Langmuir and Sips isothermal equations. This study presented a novel sorbent material for efficiently removing radioactive metals and antibiotics from wastewater.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: the biology of a neglected disease

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a chronic, debilitating disease characterised by a wide range of symptoms that severely impact all aspects of life. Despite its significant prevalence, ME/CFS remains one of the most understudied and misunderstood conditions in modern medicine. ME/CFS lacks standardised diagnostic criteria owing to variations in both inclusion and exclusion criteria across different diagnostic guidelines, and furthermore, there are currently no effective treatments available. Moving beyond the traditional fragmented perspectives that have limited our understanding and management of the disease, our analysis of current information on ME/CFS represents a significant paradigm shift by synthesising the disease's multifactorial origins into a cohesive model. We discuss how ME/CFS emerges from an intricate web of genetic vulnerabilities and environmental triggers, notably viral infections, leading to a complex series of pathological responses including immune dysregulation, chronic inflammation, gut dysbiosis, and metabolic disturbances. This comprehensive model not only advances our understanding of ME/CFS's pathophysiology but also opens new avenues for research and potential therapeutic strategies. By integrating these disparate elements, our work emphasises the necessity of a holistic approach to diagnosing, researching, and treating ME/CFS, urging the scientific community to reconsider the disease's complexity and the multifaceted approach required for its study and management.

Assessing potential drug-drug interactions between clofazimine and other frequently used agents to treat drug-resistant tuberculosis

Clofazimine is included in drug regimens to treat rifampicin/drug-resistant tuberculosis (DR-TB), but there is little information about its interaction with other drugs in DR-TB regimens. We evaluated the pharmacokinetic interaction between clofazimine and isoniazid, linezolid, levofloxacin, and cycloserine, dosed as terizidone. Newly diagnosed adults with DR-TB at Klerksdorp/Tshepong Hospital, South Africa, were started on the then-standard treatment with clofazimine temporarily excluded for the initial 2 weeks. Pharmacokinetic sampling was done immediately before and 3 weeks after starting clofazimine, and drug concentrations were determined using validated liquid chromatography-tandem mass spectrometry assays. The data were interpreted with population pharmacokinetics in NONMEM v7.5.1 to explore the impact of clofazimine co-administration and other relevant covariates on the pharmacokinetics of isoniazid, linezolid, levofloxacin, and cycloserine. Clofazimine, isoniazid, linezolid, levofloxacin, and cycloserine data were available for 16, 27, 21, 21, and 6 participants, respectively. The median age and weight for the full cohort were 39 years and 52 kg, respectively. Clofazimine exposures were in the expected range, and its addition to the regimen did not significantly affect the pharmacokinetics of the other drugs except levofloxacin, for which it caused a 15% reduction in clearance. A posteriori power size calculations predicted that our sample sizes had 97%, 90%, and 87% power at P < 0.05 to detect a 30% change in clearance of isoniazid, linezolid, and cycloserine, respectively. Although clofazimine increased the area under the curve of levofloxacin by 19%, this is unlikely to be of great clinical significance, and the lack of interaction with other drugs tested is reassuring.

Efficient Removal of Ciprofloxacin from Contaminated Water via Polystyrene Anion Exchange Resin with Nanoconfined Zero-Valent Iron

Ciprofloxacin (CIP), an important emerging contaminant, has been frequently detected in water, and its efficient removal has become an issue of great concern. In this study, a nanocomposite material nZVI/PA was synthesized by impregnating nanoscale zero-valent iron (nZVI) inside a millimeter-sized porous host (polystyrene-based anion exchange resin (PA)) for CIP removal. The nZVI/PA composite was characterized by field emission scanning electron microscopy coupled with energy-dispersive X-ray, transmission electron microscopy, X-ray diffraction, as well as X-ray photoelectron spectroscopy, and it was confirmed that nZVI was uniformly dispersed in PA with a small particle size. Furthermore, several key factors were investigated including initial solution pH, initial CIP concentration, co-existing ions, organic ligands, and dissolved oxygen. The experimental results indicated that the nZVI/PA composites exhibited a high removal efficiency for CIP under the conditions of initial pH 5.0, and initial CIP concentration 50 mg L^-1 at 25 °C, with the maximum removal rate of CIP reaching 98.5%. Moreover, the nZVI/PA composites exhibited high efficiency even after five cycles. Furthermore, quenching tests and electron spin resonance (ESR) confirmed that CIP degradation was attributed to hydroxyl (·OH) and superoxide radicals (⋅O2-). Finally, the main degradation products of CIP were analyzed, and degradation pathways including the hydroxylation of the quinolone ring, the cleavage of the piperazine ring, and defluorination were proposed. These results are valuable for evaluating the practical application of nZVI/PA composites for the removal of CIP and other fluoroquinolone antibiotics.

Design and Synthesis of Thionated Levofloxacin: Insights into a New Generation of Quinolones with Potential Therapeutic and Analytical Applications

Levofloxacin is a widely used fluoroquinolone in several infectious diseases. The structure–activity relationship of levofloxacin has been studied. However, the effect of changing the carbonyl into thiocarbonyl of levofloxacin has not been investigated up to the date of this report. In this work, levofloxacin structure was slightly modified by making a thionated form (compound 3), which was investigated for its antibacterial activity, biocompatibility, and cytotoxicity, as well as spectroscopic properties. The antibacterial susceptibility testing against five different bacteria showed promising minimum inhibitory concentrations (MICs), particularly against B. spizizenii and E. coli, with an MIC value of 1.9 µM against both bacteria, and 7.8 µM against P. mirabilis. The molecular docking experiment showed similar binding interactions of both levofloxacin and compound 3 with the active site residues of topoisomerase IV. The biocompatibility and cytotoxicity results revealed that compound 3 was more biocompatible with normal cells and more cytotoxic against cancer cells, compared to levofloxacin. Interestingly, compound 3 also showed an excitation profile with a distinctive absorption peak at λ_max 404 nm. Overall, our results suggest that the thionation of quinolones may provide a successful approach toward a new generation with enhanced pharmacokinetic and safety profiles and overall activity as potential antibacterial agents.

Proteome Exploration of Legionella pneumophila To Identify Novel Therapeutics: a Hierarchical Subtractive Genomics and Reverse Vaccinology Approach

Legionella pneumophila is the causative agent of a severe type of pneumonia (lung infection) called Legionnaires' disease. It is emerging as an antibiotic-resistant strain day by day. Hence, identifying novel drug targets and vaccine candidates is essential to fight against this pathogen. Here, attempts were taken through a subtractive genomics approach on the complete proteome of L. pneumophila to address the challenges of multidrug resistance. A total of 2,930 proteins from L. pneumophila proteome were investigated through diverse subtractive proteomics approaches, e.g., identification of human nonhomologous and pathogen-specific essential proteins, druggability and "anti-target" analysis, subcellular localization prediction, human microbiome nonhomology screening, and protein-protein interaction studies to find out effective drug and vaccine targets. Only three fulfilled these criteria and were proposed as novel drug targets against L. pneumophila. Furthermore, outer membrane protein TolB was identified as a potential vaccine target with a better antigenicity score. Antigenicity and transmembrane topology screening, allergenicity and toxicity assessment, population coverage analysis, and a molecular docking approach were adopted to generate the most potent epitopes. The final vaccine was constructed by the combination of highly immunogenic epitopes, along with suitable adjuvant and linkers. The designed vaccine construct showed higher binding interaction with different major histocompatibility complex (MHC) molecules and human immune TLR-2 receptors with minimum deformability at the molecular level. The present study aids the development of novel therapeutics and vaccine candidates for efficient treatment and prevention of L. pneumophila infections. However, further wet-lab-based phenotypic and genomic investigations and in vivo trials are highly recommended to validate our prediction experimentally. IMPORTANCE Legionella pneumophila is a human pathogen distributed worldwide, causing Legionnaires' disease (LD), a severe form of pneumonia and respiratory tract infection. L. pneumophila is emerging as an antibiotic-resistant strain, and controlling LD is now difficult. Hence, developing novel drugs and vaccines against L. pneumophila is a major research priority. Here, the complete proteome of L. pneumophila was considered for subtractive genomics approaches to address the challenge of antimicrobial resistance. Our subtractive proteomics approach identified three potential drug targets that are promising for future application. Furthermore, a possible vaccine candidate, "outer membrane protein TolB," was proposed using reverse vaccinology analysis. The constructed vaccine candidate showed higher binding interaction with MHC molecules and human immune TLR-2 receptors at the molecular level. Overall, the present study aids in developing novel therapeutics and vaccine candidates for efficient treatment of the infections caused by L. pneumophila.

Overview of the Clinical and Molecular Features of Legionella Pneumophila: Focus on Novel Surveillance and Diagnostic Strategies

Legionella pneumophila (L. pneumophila) is one of the most threatening nosocomial pathogens. The implementation of novel and more effective surveillance and diagnostic strategies is mandatory to prevent the occurrence of legionellosis outbreaks in hospital environments. On these bases, the present review is aimed to describe the main clinical and molecular features of L. pneumophila focusing attention on the latest findings on drug resistance mechanisms. In addition, a detailed description of the current guidelines for the disinfection and surveillance of the water systems is also provided. Finally, the diagnostic strategies available for the detection of Legionella spp. were critically reviewed, paying the attention to the description of the culture, serological and molecular methods as well as on the novel high-sensitive nucleic acid amplification systems, such as droplet digital PCR.

Ab initio molecular dynamics simulations and experimental speciation study of levofloxacin under different pH conditions

Levofloxacin is an extensively employed broad-spectrum antibiotic belonging to the fluoroquinolone class. Despite the extremely wide usage of levofloxacin for a plethora of diseases, the molecular characterization of this antibiotic appears quite poor in the literature. Moreover, the acid-base properties of levofloxacin - crucial for the design of efficient removal techniques from wastewaters - have never extensively been investigated so far. Here we report on a study on the behavior of levofloxacin under standard and diverse pH conditions in liquid water by synergistically employing static quantum-mechanical calculations along with experimental speciation studies. Furthermore, with the aim of characterizing the dynamics of the water solvation shells as well as the protonation and deprotonation mechanisms, here we present the unprecedented quantum-based simulation of levofloxacin in aqueous environments by means of state-of-the-art density-functional-theory-based molecular dynamics. This way, we prove the cooperative role played by the aqueous hydration shells in assisting the proton transfer events and, more importantly, the key place held by the nitrogen atom binding the methyl group of levofloxacin in accepting excess protons eventually present in water. Finally, we also quantify the energetic contribution associated with the presence of a H-bond internal to levofloxacin which, on the one hand, stabilizes the ground-state molecular structure of this antibiotic and, on the other, hinders the first deprotonation step of this fluoroquinolone. Among other things, the synergistic employment of quantum-based calculations and speciation experiments reported here paves the way toward the development of targeted removal approaches of drugs from wastewaters.

Determination of levofloxacin by HPLC with fluorescence detection in human breast milk

Aim: A new HPLC method with fluorescence detection has been developed and validated for the determination of levofloxacin, one of the fluoroquinolone class antibiotics, in breast milk. Materials & methods: Chromatographic separation was carried out on a reversed phase C18 column with acetonitrile and 10 mM o-phosphoric acid (25:75, v/v) mobile phase composition. Moxifloxacin was used as internal standard and the peaks were detected by fluorescence detection. Results & conclusion: Calibration graph was found linearly within the range of 2.5-500 ng/ml. Limit of detection and limit of quantification were found to be 0.63 and 2.11 ng/ml, respectively. Mean absolute recovery was 96.18%. The developed method has been successfully applied to the determination of levofloxacin in human breast milk taken from two healthy volunteers.

Pharmacokinetic evaluation of roxithromycin and ciprofloxacin in treating complicated avian mycoplasmosis in broiler chickens

The use of roxithromycin along with ciprofloxacin is having potential to be a promising antimicrobial therapy to treat complicated avian mycoplasmosis in broiler chickens. The present research was undertaken to study the influence of roxithromycin (20 mg/kg body weight) and ciprofloxacin (10 mg/kg body weight) on the oral pharmacokinetics of each other, when both drugs are concomitantly administered in eight healthy male broiler chickens (n=8) and to establish their therapeutic dosage regimens. Their plasma concentrations were assayed by validated ultra high performance liquid chromatography (UHPLC) methods using UV detector. Oral pharmacokinetic parameters were calculated from plasma concentration versus time data based on non-compartmental analysis. Statistically, plasma roxithromycin concentration was significantly higher at one time point only (0.5 h) and plasma ciprofloxacin concentration was significantly lower at the time point of 2 h only when used in combination, in comparison to their respective values obtained after their alone administrations. The pharmacokinetic parameters of roxithromycin and ciprofloxacin showed no significant effect on values of either drug when given in combination and there was a lack of pharmacokinetic interaction between the two antimicrobials. The predicted effective oral dose rate of roxithromycin was 20 mg/kg body weight, every 12 h, and that of ciprofloxacin was 10 mg/kg body weight, every 24 h, to treat complicated avian mycoplasmosis in broiler chickens.

Prescribed drugs containing nitrogen heterocycles: an overview

Heteroatoms as well as heterocyclic scaffolds are frequently present as the common cores in a plethora of active pharmaceuticals natural products. Statistically, more than 85% of all biologically active compounds are heterocycles or comprise a heterocycle and most frequently, nitrogen heterocycles as a backbone in their complex structures. These facts disclose and emphasize the vital role of heterocycles in modern drug design and drug discovery. In this review, we try to present a comprehensive overview of top prescribed drugs containing nitrogen heterocycles, describing their pharmacological properties, medical applications and their selected synthetic pathways. It is worth mentioning that the reported examples are actually limited to current top selling drugs, being or containing N-heterocycles and their synthetic information has been extracted from both scientific journals and the wider patent literature.

A review of recent advances in anti-tubercular drug development

Tuberculosis is a global threat but in particular affects people from developing countries. It is thought that nearly a third of the population of the world live with its causative bacteria in a dormant form. Although tuberculosis is a curable disease, the chances of cure become slim as the disease becomes multidrug-resistant and the situation gets even worse as the disease becomes extensively drug-resistant. After approximately 5 decades without any new TB drug in the pipeline, there has been some good news in the recent years with the discovery of new drugs such as bedaquiline and delamanid as well as the discovery of new classes of anti-tubercular drugs. Some old drugs such as clofazimine, linezolid and many others which were not previously indicated for tuberculosis have been also repurposed for tuberculosis and they are performing well.

Levofloxacin-induced Desquamation: A Possible and Rare Case Report

Introduction:

Levofloxacin is a fluoroquinolone active against both gram-negative and gram-positive bacteria with a well-defined margin of safety and efficacy. It has various labeled adverse effects like other fluoroquinolones but its adverse effect like desquamation is rarely reported.

Methods:

We present a case report of levofloxacin-induced desquamation in an Indian patient.

Case Report:

A-38-year old female patient presented to the outpatient department, with chief complaints of peeling off her epidermal skin. Initially, Desquamation started on her greater finger, which slowly spread to her hand, feet, lower limbs as well as upper limb and neck region. She was prescribed Levofloxacin for respiratory tract infection.

Results and Discussion:

Considering temporal relationship, upon causality assessment, (Adverse Drug Reaction) ADR was found to be likely, moderate and probable. The drug was withdrawn along with the initiation of supportive therapy and reaction subsided.

Discussion:

Although adverse drug reactions like desquamation are not fatal, this induces anxiety in the patients and reduces patient’s quality of life. This case report will help keep physicians vigilant about the current adverse drug reaction, helping in the early detection and management of ADR.

Comparison of high-performance liquid chromatography and ultraviolet-visible spectrophotometry to determine the best method to assess Levofloxacin released from mesoporous silica microspheres/nano-hydroxyapatite composite scaffolds

An assessment of Levofloxacin by high-performance liquid chromatography (HPLC) or ultraviolet-visible spectrophotometry (UV-Vis) and its pharmacokinetics in serum or plasma was made in a previous study by the present authors. Levofloxacin-loaded mesoporous silica microspheres/nano-hydroxyapatite (n-HA) composite scaffolds comprise a novel synthetic composite scaffold that may be utilized as a drug-delivery system for clinical usage. However, few studies have been published concerning a comparison of HPLC with UV-Vis, which is the preferred method for determination of Levofloxacin. In the present study, an HPLC method was first established, and subsequently a comparison of HPLC with the UV-Vis method was performed. The standard curve was established, and recovery rate from simulated body fluid was calculated. The linear concentration range for Levofloxacin was 0.05–300 µg/ml. The regression equation for HPLC was y=0.033x+0.010, with R²=0.9991, whereas that for UV-Vis was y=0.065x+0.017, with R²=0.9999. The recovery rates of low, medium and high (5, 25 and 50 µg/ml) concentrations of Levofloxacin determined by HPLC were 96.37±0.50, 110.96±0.23 and 104.79±0.06%, respectively, whereas those for low, medium and high concentrations according to UV-Vis were 96.00±2.00, 99.50±0.00 and 98.67±0.06%, respectively. Taken together, these findings demonstrated that it is not accurate to measure the concentration of drugs loaded on the biodegradable composite composites by UV-Vis. HPLC is the preferred method to evaluate sustained release characteristics of Levofloxacin released from mesoporous silica microspheres/n-HA composite scaffolds. The present study also provides guidance on which methods should be selected for investigating the sustained release properties of drugs in tissue engineering. The accurate determination of drug concentration in the drug delivery system provides guidance for the treatment of infectious diseases.

Aqueous and Vitreous Penetration of Levofloxacin after Topical and/or Oral Administration

PURPOSE

To investigate the aqueous and vitreous penetration of levofloxacin, the drug was administered topically and/or orally to patients undergoing vitrectomy.

METHODS

Thirty-six patients undergoing initial vitrectomy with phacoemulsification and aspiration (PEA) were enrolled, and were divided randomly into three groups. Group 1 was treated with topical application of levofloxacin (three times on the day before surgery and seven times on the day of surgery), Group 2 received oral administration of levofloxacin (200 mg twice on the day before surgery and 200 mg at 3 hours before surgery), and Group 3 received both topical and oral levofloxacin according to the above schedules. The concentration of levofloxacin was measured in aqueous humor and vitreous fluid samples obtained during surgery.

RESULTS

In Groups 1, 2, and 3, the mean levofloxacin concentration in aqueous humor was 0.765+/-0.624 micro g/mL, 1.279+/-0.440 micro g/mL, and 1.823+/-0.490 micro g/mL, respectively, while the mean levofloxacin concentration in vitreous fluid was <0.02 micro g/mL, 1.455+/-0.445 micro g/mL, and 1.369+/-0.530 micro g/mL, respectively.

CONCLUSIONS

Oral administration of levofloxacin at a dose of 400 mg/day was sufficient for the prophylaxis of ocular infections, because the drug concentrations in both aqueous humor and vitreous fluid were higher than the MIC90 values for major ocular pathogens. Topical application of levofloxacin achieved adequate drug levels in aqueous humor, but not in vitreous fluid, while combined topical and oral administration had an additive effect on the drug concentration in aqueous humor.

Fluoroquinolone-induced serious, persistent, multisymptom adverse effects

We present a case series of four previously healthy, employed adults without significant prior medical history in each of whom symptoms developed while on fluoroquinolones (FQs), with progression that continued following discontinuation evolving to a severe, disabling multisymptom profile variably involving tendinopathy, muscle weakness, peripheral neuropathy, autonomic dysfunction, sleep disorder, cognitive dysfunction and psychiatric disturbance. Physicians and patients should be alert to the potential for FQ-induced severe disabling multisymptom pathology that may persist and progress following FQ use. Known induction by FQs of delayed mitochondrial toxicity provides a compatible mechanism, with symptom profiles (and documented mechanisms of FQ toxicity) compatible with the hypothesis of an exposure-induced mitochondrial neurogastrointestinal encephalomyopathy.

Correlation between GyrA substitutions and ofloxacin, levofloxacin, and moxifloxacin cross-resistance in Mycobacterium tuberculosis

The newer fluoroquinolones moxifloxacin (MXF) and levofloxacin (LVX) are becoming more common components of tuberculosis (TB) treatment regimens. However, the critical concentrations for testing susceptibility of Mycobacterium tuberculosis to MXF and LVX are not yet well established. Additionally, the degree of cross-resistance between ofloxacin (OFX) and these newer fluoroquinolones has not been thoroughly investigated. In this study, the MICs for MXF and LVX and susceptibility to the critical concentration of OFX were determined using the agar proportion method for 133 isolates of M. tuberculosis. Most isolates resistant to OFX had LVX MICs of >1 μg/ml and MXF MICs of >0.5 μg/ml. The presence of mutations within the gyrA quinolone resistance-determining regions (QRDR) correlated well with increased MICs, and the level of LVX and MXF resistance was dependent on the specific gyrA mutation present. Substitutions Ala90Val, Asp94Ala, and Asp94Tyr resulted in low-level MXF resistance (MICs were >0.5 but ≤2 μg/ml), while other mutations led to MXF MICs of >2 μg/ml. Based on these results, a critical concentration of 1 μg/ml is suggested for LVX and 0.5 μg/ml for MXF drug susceptibility testing by agar proportion with reflex testing for MXF at 2 μg/ml.

Targeting the gyrase of Plasmodium falciparum with topoisomerase poisons

Drug-resistant malaria poses a major public health problem throughout the world and the need for new antimalarial drugs is growing. The apicoplast, a chloroplast-like organelle essential for malaria parasite survival and with no counterpart in humans, offers an attractive target for selectively toxic new therapies. The apicoplast genome (plDNA) is a 35 kb circular DNA that is served by gyrase, a prokaryotic type II topoisomerase. Gyrase is poisoned by fluoroquinolone antibacterials that stabilize a catalytically inert ternary complex of enzyme, its plDNA substrate, and inhibitor. We used fluoroquinolones to study the gyrase and plDNA of Plasmodium falciparum. New methods for isolating and separating plDNA reveal four topologically different forms and permit a quantitative exam of perturbations that result from gyrase poisoning. In keeping with its role in DNA replication, gyrase is most abundant in late stages of the parasite lifecycle, but several lines of evidence indicate that even in these cells the enzyme is present in relatively low abundance: about 1 enzyme for every two plDNAs or a ratio of 1 gyrase: 70 kb DNA. For a spectrum of quinolones, correlation was generally good between antimalarial activity and gyrase poisoning, the putative molecular mechanism of drug action. However, in P. falciparum there is evidence for off-target toxicity, particularly for ciprofloxacin. These studies highlight the utility of the new methods and of fluoroquinolones as a tool for studying the in situ workings of gyrase and its plDNA substrate.

Comparison of Drug Concentrations in Human Aqueous Humor after the Administration of 0.3% Gatifloxacin Ophthalmic Gel, 0.3% Gatifloxacin and 0.5% Levofloxacin Ophthalmic Solutions

PURPOSE

To investigate the penetration of 0.3% gatifloxacin ophthalmic gel, 0.3% gatifloxacin ophthalmic solution and 0.5% levofloxacin ophthalmic solution into aqueous humor after topical application.

MATERIALS AND METHODS

Age-related cataract patients (150 eyes in 150 cases) receiving phacoemulsification were randomly divided into three groups: a 0.3% gatifloxacin gel group (n=50), a 0.3% gatifloxacin solution group (n=50), and a 0.5% levofloxacin solution group (n=50). Each group was administered one drop of gel or solution every 15 minutes for four doses. Aqueous samples were collected at different time points after the last drop. High pressure liquid chromatography (HPLC) was applied to determine the concentrations. The one-way ANOVA analysis was performed.

RESULTS

Our data indicated that the concentration of the gatifloxacin gel group was higher than that of the gatifloxacin solution group at all time points (P <0.05); moreover, the gatifloxacin gel group exhibited higher levels than the levofloxacin solution group at 120.0 min and 180.0 min (P<0.05). Furthermore, the gatifloxacin gel produced the highest concentration at 120.0 min, and the gatifloxacin and levofloxacin solutions reached their peak values at 60.0 min.

CONCLUSIONS

0.3% gatifloxacin ophthalmic gel application produced highest aqueous humor drug concentration, maintained the longest time, had the best penetration and bioavailability.

The pharmacokinetic interaction between levofloxacin and sunitinib

BACKGROUND

The aim of this study was to evaluate the impact of sunitinib on pharmacokinetics of levofloxacin. The previous study proved that levofloxacin co-administered with sunitib changes the following pharmacokinetic parameters i.e. Cmax and AUC for both sunitinib and SU012662 (sunitinib metabolite). We will also investigate if the limited sample strategy can be applied for levofloxacin.

METHODS

Rabbits were divided into two groups. In both groups there were six animals. In the control group levofloxacin was administered and in investigated group levofloxacin and sunitinib were co-administered. The dose of levofloxacin was 20mg/kg and the dose of sunitinib was 25mg. The concentration in plasma was determined by HPLC-FLD. The pharmacokinetic parameters were evaluated by WinNonLin software. The results were evaluated by the following statistical tests: Shapiro-Wilk, t-Student and Mann-Whitney test.

RESULTS

Pharmacokinetics of levofloxacin obeys the two-compartment model. Sunitinib influences the following pharmacokinetic parameters of levofloxacin: half-life, elimination constant and volume of distribution. Statistical analysis proved that there is a correlation between AUC and the following five time-points: 0.25 h, 4h, 6h, 10h and 12h.

CONCLUSIONS

The study proved that there is a potential pharmacokinetic interaction between sunitinib and levofloxacin. The statistical analysis proved that the limited sample strategy can be applied for levofloxacin.

Discovery of FDA-approved drugs as inhibitors of fatty acid binding protein 4 using molecular docking screening

We first identified fluorescein, ketazolam, antrafenine, darifenacin, fosaprepitant, paliperidone, risperidone, pimozide, trovafloxacin, and levofloxacin as inhibitors of fatty acid binding protein 4 using molecular docking screening from FDA-approved drugs. Subsequently, the biochemical characterizations showed that levofloxacin directly inhibited FABP4 activity in both the in vitro ligand displacement assay and cell-based function assay. Furthermore, levofloxacin did not induce adipogenesis in adipocytes, which is the major adverse effect of FABP4 inhibitors.

A controlled release of antibiotics from calcium phosphate-coated poly(lactic-co-glycolic acid) particles and their in vitro efficacy against Staphylococcus aureus biofilm

Ceramic-polymer hybrid particles, intended for osteomyelitis treatment, were fabricated by preparing poly(lactic-co-glycolic acid) particles through an emulsion solvent evaporation technique, followed by calcium phosphate (CaP) coating via a surface adsorption-nucleation method. The presence of CaP coating on the surface of the particles was confirmed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. Subsequently, two antibiotics for treating bone infection, nafcillin (hydrophilic) and levofloxacin (amphiphilic), were loaded into these hybrid particles and their in vitro drug release studies were investigated. The CaP coating was shown to reduce burst release, while providing sustained release of the antibiotics for up to 4 weeks. In vitro bacterial study against Staphylococcus aureus demonstrated the capability of these antibiotic-loaded hybrid particles to inhibit biofilm formation as well as deteriorate established biofilm, making this hybrid system a potential candidate for further investigation for osteomyelitis treatment.

Levofloxacin and proton pump inhibitor-based triple therapy versus standard triple first-line therapy for Helicobacter pylori eradication

BACKGROUND

Standard triple therapy for Helicobacter pylori infection fails in up to one quarter of patients. Levofloxacin-based triple therapy may be more efficacious.

OBJECTIVE

The aim of this paper was to compare levofloxacin and proton pump inhibitor-based triple therapy with standard triple therapy for H. pylori infection.

METHODS

PubMed, Embase, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, Google Scholar, and Ovid were systematically searched to identify randomized controlled trials comparing levofloxacin and proton pump inhibitor-based therapy with standard triple therapy in treatment-naive patients with H. pylori infection until August 2013.

RESULTS

Ten randomized controlled trials involving 2676 patients (1357 in the levofloxacin group and 1319 in the control group) met the inclusion criteria. The pooled odds ratio by intention-to-treat analysis and by per protocol analysis in the levofloxacin regimen versus standard regimen was 1.28 [95% confidence interval (CI): 0.88-1.85] and 1.23 (95% CI: 0.82-1.84) by the random effects model, respectively. There was no statistical significance of the incidence of total side effects between the groups, but levofloxacin-based therapy was associated with a significant reduction in the incidence of taste disturbance compared with standard third therapy.

CONCLUSION

Levofloxacin-based therapy was as safe and effective as triple therapy for H. pylori infection and could be considered as an additional treatment option. However, more rigorous research is required to accurately assess the role of levofloxacin in eradicating H. pylori infection.

Simultaneous determination of the combined drugs of ceftriaxone sodium, metronidazole, and levofloxacin in human urine by high-performance liquid chromatography

AIM

To develop a new high-performance liquid chromatography (HPLC) method for simultaneous determination of the combined drugs (ceftriaxone sodium, metronidazole, and levofloxacin) in human urine.

METHODS

Ceftriaxone sodium, metronidazole, and levofloxacin were separated on a Kromasil 100-5 C18 (250 mm × 4.6 mm, 5 μm, AKZO NOBEL, Bohus, Sweden) analytical column, using the mobile phase consisted of 1.5 mM KH(2) PO(4) (pH 4.5) with 0.0125% triethylamine-methnol (70:30, v/v). Ceftriaxone sodium, metronidazole, and levofloxacin were detected by a photodiode-array detector at 247, 320, 292 nm, respectively.

RESULTS

Under optimal conditions, the effective separation of ceftriaxone sodium, metronidazole, and levofloxacin was achieved. A good linearity with the correlation coefficients more than 0.999 was demonstrated. The detection limits of ceftriaxone sodium, metronidazole, and levofloxacin were 0.05, 0.01, and 0.25 μg/ml, respectively, and the average recoveries in human urine were in the range from 97.73 to 100.7% with the average relative standard deviation (RSD) in the range of 2.5% and 3.0%.

CONCLUSION

The proposed method was sensitive, accurate, and rapid. This work may provide a reference for clinical rational drug use and methodology for the pharmacokinetics study of the combined drugs.

Levofloxacin/amoxicillin-based schemes vs quadruple therapy for Helicobacter pylori eradication in second-line

Worldwide prevalence of Helicobacter pylori (H. pylori) infection is approximately 50%, with the highest being in developing countries. We compared cure rates and tolerability (SE) of second-line anti-H. pylori levofloxacin/amoxicillin (LA)-based triple regimens vs standard quadruple therapy (QT). An English language literature search was performed up to October 2010. A meta-analysis was performed including randomized clinical trials comparing 7- or 10-d LA with 7-d QT. In total, 10 articles and four abstracts were identified. Overall eradication rate in LA was 76.5% (95% CI: 64.4%-97.6%). When only 7-d regimens were included, cure rate was 70.6% (95% CI: 40.2%-99.1%), whereas for 10-d combinations, cure rate was significantly higher (88.7%; 95% CI: 56.1%-109.9%; P < 0.05). Main eradication rate for QT was 67.4% (95% CI: 49.7%-67.9%). The 7-d LA and QT showed comparable efficacy [odds ratio (OR): 1.09; 95% CI: 0.63-1.87], whereas the 10-d LA regimen was significantly more effective than QT (OR: 5.05; 95% CI: 2.74-9.31; P < 0.001; I(2) = 75%). No differences were reported in QT eradication rates among Asian and European studies, whereas LA regimens were more effective in European populations (78.3% vs 67.7%; P = 0.05). Incidence of SE was lower in LA therapy than QT (OR: 0.39; 95% CI: 0.18-0.85; P = 0.02). A higher rate of side effects was reported in Asian patients who received QT. Our findings support the use of 10-d LA as a simple second-line treatment for H. pylori eradication with an excellent eradication rate and tolerability. The optimal second-line alternative scheme might differ among countries depending on quinolone resistance.

Quinolones: review of psychiatric and neurological adverse reactions

Quinolones are a class of antibacterial agents for the treatment of several infectious diseases (e.g. urinary and respiratory tract infections). They are used worldwide due to their broad spectrum of activity, high bioavailability and good safety profile. The safety profile varies from quinolone to quinolone. The aim of this article was to review the neurological and psychiatric adverse drug reaction (ADR) profile of quinolones, using a literature search strategy designed to identify case reports and case series. A literature search using PubMed/MEDLINE (from inception to 31 October 2010) was performed to identify case reports and case series related to quinolone-associated neurological and psychiatric ADRs. The search was conducted in two phases: the first phase was the literature search and in the second phase relevant articles were identified through review of the references of the selected articles. Relevant articles were defined as articles referring to adverse events/reactions associated with the use of any quinolone. Abstracts referring to animal studies, clinical trials and observational studies were excluded. Identified case reports were analysed by age group, sex, active substances, dosage, concomitant medication, ambulatory or hospital-based event and seriousness, after Medical Dictionary for Regulatory Activities (MedDRA®) coding. From a total of 828 articles, 83 were identified as referring to nervous system and/or psychiatric disorders induced by quinolones. 145 individual case reports were extracted from the 83 articles. 40.7% of the individual case reports belonged to psychiatric disorders only, whereas 46.9% related to neurological disorders only. Eight (5.5%) individual case reports presented both neurological and psychiatric ADRs. Ciprofloxacin, ofloxacin and pefloxacin were the quinolones with more neurological and psychiatric ADRs reported in the literature. Ciprofloxacin has been extensively used worldwide, which may explain the higher number of reports, while for ofloxacin and pefloxacin, the number of reports may be over-representative. A total of 232 ADRs were identified from the selected articles, with 206 of these related to psychiatric and/or neurological ADRs. The other 26 were related to other body systems but were reported together with the reactions of interest. Mania, insomnia, acute psychosis and delirium were the most frequently reported psychiatric adverse events; grand mal convulsion, confusional state, convulsions and myoclonus were the most frequently reported neurological adverse events. Several aspects should be taken into account in the development of CNS adverse effects, such as the pharmacokinetics of quinolones, chemical structure and quinolone uptake in the brain. These events may affect not only susceptible patients but also 'healthy' patients.

Efficient penetration into aqueous humor by administration of oral and topical levofloxacin

PURPOSE

We investigated whether an optimized combination of oral and topical levofloxacin would lead to higher levofloxacin concentrations in aqueous humor.

METHODS

Fifteen patients with cataracts in both eyes began topical treatment at 1 week before the first surgery and oral treatment at 1 day before the first surgery. On the day of surgery, they received oral and topical levofloxacin at 4 h and 1 h before surgery, respectively. Two days after the first operation, we performed cataract surgery on the second eye with the same drug administration protocol.

RESULTS

Postsurgery concentrations of levofloxacin in the aqueous humor of the first and second eyes were 2.87±0.89 μg/mL (mean±standard deviation, n=15) and 3.76±1.32 μg/mL, respectively; the levofloxacin level in the second eye was significantly higher than that in the first eye (P=0.0085).

CONCLUSIONS

Our protocol to achieve high aqueous humor concentrations of levofloxacin may be favorable in preventing endophthalmitis after eye surgery.

Flomoxef Sodium and Levofloxacin Concentrations in Aqueous Humor

AIMS

We intravenously administered flomoxef sodium (FMOX) 120 minutes before cataract surgery, topically administered levofloxacin (LVFX) into the eyes four times at 30-minute intervals before surgery, and measured the aqueous humor concentrations of these agents to investigate their penetration into the aqueous humor and their efficacy in the prevention of postoperative endophthalmitis.

METHODS

Sixty-eight patients who underwent cataract surgery at the Department of Ophthalmology, Yokohama City University School of Medicine, or its affiliate, Kanazawa Hospital, Yokohama, were enrolled in this study. They received one or both of the following: 1.0 g FMOX via a 20-minute intravenous drip and LVFX ophthalmic solution applied four times at 30-minute intervals, both beginning two hours before the operation. Aqueous humor was aspirated from the anterior chamber and assayed for FMOX and LVFX concentrations using high-performance liquid chromatography (HPLC).

RESULTS

The mean intraoperative FMOX and LVFX concentrations in the patients' aqueous humor were 1.21 +/- 0.63 microg/ml and 0.69 +/- 0.47 microg/ml, respectively. These concentrations sufficiently exceeded the MIC90 values against Staphylococcus epidermidis, S. aureus, and Propionibacterium acnes.

CONCLUSIONS

The FMOX and LVFX concentrations in the aqueous humor sampling were adequate to kill bacteria in vitro. These drugs may have efficacy in the prevention of postoperative endophthalmitis in patients undergoing cataract surgery.

Stroke-induced immunodepression: consequences, mechanisms and therapeutic implications

The clinical picture of stroke is not only characterized by neurological deficits but also by the high incidence of infectious complications, in particular pneumonia. The occurrence of pneumonia in stroke patients is associated with higher mortality, larger neurological deficits, longer hospitalization and increased costs for medical care. Immobilization and impaired protective reflexes are known to increase the risk of aspiration pneumonia. However, recent experimental and clinical evidence indicates that stroke-induced immunodepression is an independent risk factor that increases susceptibility to infections. This review provides an update on the mechanisms and consequences of stroke-induced immunodepression. The growing insight into these mechanisms may allow new immunomodulatory treatment approaches in stroke patients in the future. In the meantime, several trials on preventive antibacterial treatment to reduce the incidence of post-stroke infections have been conducted, which will be summarized in this review.

Safety of prolonged high-dose levofloxacin therapy for bone infections

The records of 84 patients with bone infections treated with high-dose levofloxacin (i.e. 0.75-1g daily) for more than 4 weeks were reviewed. Patients were given either 500 mg b.i.d. throughout the treatment period [Group 1 (n=41)], 500 mg b.i.d. for 3 weeks and then 750 mg q.d. [Group 2 (n=21)] or 750 mg q.d. for the whole treatment period [Group 3 (n=22)]. All patients had combined therapy, including levofloxacin-rifampin in 62 cases (73.8%), for an average duration of 13.7 weeks. Muscular pain and/or tendonitis were reported in 19 patients (22.6%) which affected more patients in Groups 1 and 2 than in Group 3 (14/41 and 5/21 vs. 0/22; p=0.01 and 0.001, respectively). A dosage of 750 mg q.d. may be warranted for prolonged high-dose levofloxacin treatment in patients with bone infections rather than 500 mg b.i.d. for the entire duration of treatment, or for the first 3 weeks.

Clinical efficacy and tolerability of levofloxacin in patients with liver disease: a prospective, non comparative, observational study

The aim of this open, non comparative, observational study was to assess the clinical and bacteriological efficacy, the tolerability and safety of levofloxacin for treatment of concurrent bacterial infections in patients with chronic liver disease. Overall, 40 patients (inpatients or outpatients) were recruited to the study (28 with UTI, 6 with pneumonia, and 6 with spontaneous bacterial peritonitis (SBP)). Patients affected by UTI received 250 mg oral levofloxacin once daily for five days; patients with pneumonia or SBP underwent a 10/14-day therapeutic oral regimen with 500 mg b.i.d. Clinical evaluation and possible side effects were monitored daily both in out- and in-patients. For all patients, laboratory tests were performed at baseline and 3-4 days after the end of therapy in order to evaluate levofloxacin tolerability. Statistical analysis was performed by means of Student's t test to show differences between cases; all values are reported as means and standard deviations and p values were considered as significant when p<0.05. After treatment, clinical cure and bacteriological eradication were achieved in all patients (40/40; 100%). Adverse events, mainly gastrointestinal disturbances (e.g. nausea), were observed in 5 out of 40 patients (12.5%) and no neurotoxic effects were registered (e.g. anxiety, hallucinations, convulsions, mental confusion). No significant variation in laboratory tests due to hematic crasis and/or hepatic and renal disorders was observed. Levofloxacin proved to be highly efficacious and safe in the treatment of bacterial infections in patients affected by liver disease.

Corneal penetration of simultaneously applied topical levofloxacin, norfloxacin and lomefloxacin in human eyes

PURPOSE

This study was performed to assess the corneal penetration of three topically applied fluoroquinolones (levofloxacin, norfloxacin and lomefloxacin) in corneal buttons obtained from patients undergoing penetrating keratoplasty.

METHODS

Fourteen patients received three drops each of 0.5% levofloxacin, 0.3% norfloxacin and 0.3% lomefloxacin (the standard clinically available preparations) over a 30-min interval beginning 90 mins before their scheduled keratoplasty. Corneal samples obtained from excised buttons at the time of surgery were stored at - 80 degrees until analysis. The concentration of the administered fluoroquinolones was measured using high-performance liquid chromatography.

RESULTS

The mean corneal concentration of levofloxacin (4.6 +/- 3.5 microg/g, mean +/- standard deviation) was significantly higher than that of lomefloxacin (2.7 +/- 1.8 microg/g, p = 0.0018) and norfloxacin (1.3 +/- 1.2 microg/g, p = 0.00012).

CONCLUSION

Levofloxacin achieves a higher mean corneal concentration than norfloxacin and lomefloxacin in the human cornea.

Safety of Newer Parenteral Antibiotics

Several parenteral antimicrobials have been introduced into clinical practice over the course of the last decade. Some of these agents (e.g., linezolid, daptomycin, and tigecycline) are prototypes of new classes of compounds. In comparative clinical trials, these newer anti-infectives have been shown to be safe and to have low rates of discontinuation by patients. However, long-term use has revealed unique toxicities associated with the use of some of these drugs. The adverse events and potential drug interactions associated with the use of these antibiotics are variable and require familiarity with the safety profile of each drug. It is especially important that clinicians be able to recognize serious adverse events associated with the use of specific drugs, because most of the adverse events can be readily reversed by cessation of therapy.

The Effects of Levofloxacin on ECG Parameters and Late Potentials

In this study, our aim was to investigate the proarrhythmic effects of levofloxacin. Twenty-six patients who were diagnosed as having community-acquired pneumonia were enrolled in the study. Intravenous levofloxacin, 500 mg daily, was given, and 12-lead ECG measurements were obtained before the infusion, at 30 and 60 minutes during infusion, and 10 minutes after its cessation. Resting late potentials were recorded before and after infusion. Twelve female and 14 male patients were participated the study. Mean age was 51.3 +/- 22.3 years. Levofloxacin infusion increased the heart rate (HR) and prolonged the corrected QT (QTc) intervals significantly (baseline HR: 84.6 +/- 18.8 vs. HR at 60 minutes: 88.6 +/- 18, P = 0.02; baseline QTc: 413.5 +/- 36.9 milliseconds vs. QTc at 60 minutes: 426.1 +/- 34.7, P = 0,006). There was no significant difference between the late potential values obtained before and after infusion. None of our patients experienced severe arrhythmia that required stopping the treatment. A single dose of IV levofloxacin prolongs the QTc interval without significant change in late potentials. Monitoring ECG during levofloxacin infusion might be necessary in patients who have a condition that could affect the QTc interval.

The Early Systemic Prophylaxis of Infection After Stroke Study

Background and Purpose— Early infection after stroke is frequent but the clinical value of antibiotic prophylaxis in acute stroke has never been explored.

Objective and

Methods— The Early Systemic Prophylaxis of Infection After Stroke (ESPIAS) is a randomized, double-blind, placebo-controlled study of antibiotic prophylaxis in patients older than 18 years with nonseptic ischemic or hemorrhagic stroke enrolled within 24 hours from clinical onset. Interventions included intravenous levofloxacin (500 mg/100 mL/d, for 3 days) or placebo (0.9% physiological serum) in addition to optimal care. A sample size of 240 patients was calculated to identify a 15% absolute risk reduction of the primary outcome measure, which was the incidence of infection at day 7 after stroke. Secondary outcome measures were neurological outcome and mortality at day 90.

Results— Based on a preplanned futility analysis, the study was interrupted prematurely when 136 patients had been included. Levofloxacin and placebo patients had a cumulative rate of infection of 6% and 6% ( P =0.96) at day 1; 10% and 12% ( P =0.83) at day 2; 12% and 15% ( P =0.66) at day 3; 16% and 19% ( P =0.82) at day 7; and 30% and 33% ( P =0.70), at day 90. Using logistic regression, favorable outcome at day 90 was inversely associated with baseline National Institutes of Health Stroke Scale (OR, 0.72; 95% CI, 0.59 to 0.89; P =0.002) and allocation to levofloxacin (OR, 0.19; 95% CI, 0.04 to 0.87; P =0.03).

Conclusions— Prophylactic administration of levofloxacin (500 mg/100 mL/day for 3 days) is not better than optimal care for the prevention of infections in patients with acute stroke.

Concentrations of levofloxacin, ofloxacin, and ciprofloxacin in human corneal stromal tissue and aqueous humor after topical administration

OBJECTIVE

To evaluate the penetration of commercially available levofloxacin 0.5%, ofloxacin 0.3%, and ciprofloxacin 0.3% topical ophthalmic solutions in human corneal stromal and aqueous humor tissues.

METHODS

A total of 67 patients scheduled to undergo penetrating keratoplasty for treatment of stromal scar or dystrophy, keratoconus, pellucid marginal degeneration, or endothelial disease were enrolled in this prospective, double-blind, 3-center study. To be considered for inclusion, patients had to have an intact corneal epithelium and minimal or no corneal edema (pachymetry < 650 microm). After informed consent was obtained, patients were randomized to receive 1 drop of levofloxacin 0.5%, ofloxacin 0.3%, or ciprofloxacin 0.3% topical ophthalmic solution at approximately 15 and 10 minutes before surgery. Approximately 0.1 mL of aqueous fluid was aspirated by paracentesis through the trephination wound at the onset of surgery, followed by excision of the affected cornea and removal of its epithelium. Specimens were stored frozen at -70 degrees C until assayed by high-performance liquid chromatography.

RESULTS

All 3 fluoroquinolones were well tolerated. A total of 65 corneas and 59 aqueous fluid samples were obtained and assayed. The mean +/- standard deviation corneal concentrations of ciprofloxacin, ofloxacin, and levofloxacin following a 2-drop administration were 9.92 +/- 10.99 microg/g (n = 18), 10.77 +/- 5.90 microg/g (n = 23), and 18.23 +/- 20.51 microg/g (n = 24), respectively. Although corneal stromal levels were highest in the levofloxacin group, the high degree of interpatient variability prevented demonstration of statistically significant differences when compared with ofloxacin (P = 0.377). In contrast, levofloxacin concentrations were approximately twice as high as ciprofloxacin, and this difference reached statistical significance (P = 0.014). The corresponding aqueous humor concentrations of ciprofloxacin, ofloxacin, and levofloxacin were 0.135 +/- 0.231 microg/mL (n = 15), 0.135 +/- 0.111 microg/mL (n = 20), and 0.372 +/- 0.546 microg/mL (n = 24, P < 0.001 versus ciprofloxacin and ofloxacin).

CONCLUSION

The topical administration of all 3 agents was well tolerated in patients undergoing penetrating keratoplasty. Two drops of levofloxacin 0.5% solution results in a 1.7- to 2.7-fold greater penetration into human corneal stromal and aqueous humor tissues than ofloxacin 0.3% or ciprofloxacin 0.3%. The mean intracorneal concentrations of all three agents following 2 drops exceeds the MIC90 for the majority of pathogens causing bacterial keratitis. Topical levofloxacin appears to offer pharmacokinetic and pharmacodynamic advantages over ofloxacin and ciprofloxacin in terms of enhanced transcorneal penetration; however, clinical comparative trials are needed to confirm these relative advantages.

Aqueous humor levels of topically applied levofloxacin, norfloxacin, and lomefloxacin in the same human eyes

PURPOSE

To assess the relative penetration of topical eyedrops of 3 fluoroquinolones into the aqueous humor in human eyes.

SETTING

Department of Ophthalmology, Sano-Kosei Hospital, Sano, Japan.

METHODS

Fifty-nine cataract patients (36 women, 23 men) received 3 drops each of levofloxacin 0.5%, norfloxacin 0.3%, and lomefloxacin 0.3% in the same eye at 15-minute intervals beginning 90 minutes before cataract surgery. At the beginning of surgery, 50 microL of aqueous humor was aspirated from the anterior chamber and stored at -80 degrees C until analyzed. The drug concentrations in the samples were analyzed using high-performance liquid chromatography.

RESULTS

Five patients were excluded from the study because their sample volumes were insufficient. Norfloxacin was detected in 3 patients; the mean aqueous humor level was 0.10 microg/mL +/- 0.02 (SD). Levofloxacin was detected in all cases; the mean aqueous humor level was 0.60 +/- 0.28 microg/mL (n = 54). Lomefloxacin was not detected in 10 patients; the mean aqueous humor level was 0.23 +/- 0.11 microg/mL (n = 44).

CONCLUSION

Topically applied levofloxacin had better penetration into the aqueous humor than lomefloxacin and norfloxacin.

Once-daily, high-dose levofloxacin versus ticarcillin-clavulanate alone or followed by amoxicillin-clavulanate for complicated skin and skin-structure infections: a randomized, open-label trial

This study tested whether levofloxacin, at a new high dose of 750 mg, was effective for the treatment of complicated skin and skin-structure infections (SSSIs). Patients with complicated SSSIs (n=399) were randomly assigned in a ratio of 1:1 to 2 treatment arms: levofloxacin (750 mg given once per day intravenously [iv], orally, or iv/orally) or ticarcillin-clavulanate (TC; 3.1 g given iv every 4-6 hours) followed, at the investigator's discretion, by amoxicillin-clavulanate (AC; 875 mg given orally every 12 hours). In the clinically evaluable population, therapeutic equivalence was demonstrated between the levofloxacin and TC/AC regimens (success rates of 84.1% and 80.3%, respectively). In the microbiologically evaluable population, the overall rate of eradication was 83.7% in the levofloxacin treatment group and 71.4% in the TC/AC treatment group (95% confidence interval, -24.3 to -0.2). Both levofloxacin and TC/AC were well tolerated. These data demonstrate that levofloxacin (750 mg once per day) is safe and at least as effective as TC/AC for complicated SSSIs.

Aqueous humor levels of topically applied levofloxacin in human eyes

PURPOSE

To evaluate transcorneal penetration of topically applied 0.5% levofloxacin into the aqueous humor in human eyes.

METHODS

Twenty cataract patients (14 females, 6 males) received 3 drops of 0.5% levofloxacin at 15 min intervals from 90 minutes before the surgery. At the beginning of the cataract surgery, 50 microL of aqueous humor was aspirated from the anterior chamber and stored at -80 degrees C until analysis. The drug concentration of the samples was analyzed using high-performance liquid chromatography.

RESULTS

A mean aqueous humor level of levofloxacin was 1.00 +/- 0.48 microg/mL (mean +/- standard deviation, n = 20), ranging from 0.30 microg/mL to 2.32 microg/mL.

CONCLUSIONS

The mean concentration of levofloxacin in the aqueous humor was higher than the MIC(90) values against some common pathogens of postoperative endophthalmitis, although a great degree of interpatient variability was present.