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

Quantum dot-based fluorescence-linked immunosorbent assay for the rapid detection of lomefloxacin in animal-derived foods

Lomefloxacin (LMF), a third-generation fluoroquinolone antibacterial agent, is often used to treat bacterial and mycoplasma infections. However, due to its prolonged half-life and slow metabolism, it is prone to residues in animal-derived foods, posing a potential food safety risk. Therefore, it is particularly urgent and important to establish a method for detecting lomefloxacin. In this study, direct and indirect competitive fluorescence-linked immunosorbent assay (dc-FLISA and ic-FLISA) based on quantum dots (QDs) was established for the detection of LMF. As for dc-FLISA, the half-maximal inhibitory concentration (IC50) and limit of detection (LOD) were 0.84 ng/mL, 0.04 ng/mL, respectively, the detection ranges from 0.08 to 9.11 ng/mL. The IC50 and LOD of ic-FLISA were 0.43 ng/mL and 0.03 ng/mL, respectively, meanwhile the detection ranges from 0.05 to 3.49 ng/mL. The recoveries of dc-FLISA and ic-FLISA in animal-derived foods (milk, fish, chicken, and honey), ranged from 95.8% to 105.2% and from 96.3% to 103.4%, respectively, with the coefficients of variation less than 8%. These results suggest that the dc-FLISA and ic-FLISA methods, which are based on QD labelling, are highly sensitive and cost-effective, and can be effectively used to detect LMF in animal-derived foods.

Antibacterial and Pharmacological Evaluation of Fluoroquinolones: A Chemoinformatics Approach

Fluoroquinolone (FQ) antibiotics are an important class of synthetic antibacterial agents. These are the most extensively used drugs for treating bacterial infections in the field of both human and veterinary medicine. Herein, the antibacterial and pharmacological properties of four fluoroquinolones: lomefloxacin, norfloxacin, ciprofloxacin, and ofloxacin have been studied. The objective of this study was to analyze the antibacterial characteristics of the different fluoroquinolones. Also, the pharmacological properties of the compounds including the Lipinski rule of five, absorption, distribution, metabolism, and excretion, LD50, drug likeliness, and toxicity were evaluated. We found that among all four FQ molecules, ofloxacin showed the highest antibacterial activity through in silico assays with a strong interaction (‒38.52 kJ/mol) with the antibacterial target protein (topoisomerase-II DNA gyrase enzyme). The pharmacological and pharmacokinetic analysis also showed that the compounds ciprofloxacin, ofloxacin, lomefloxacin and norfloxacin have good pharmacological properties. Notably, ofloxacin was found to possess an IGC50 (concentration needed to inhibit 50% growth) value of 0.286 μg/L against the Tetrahymena pyriformis protozoa. It also tested negative for the Ames toxicity test, showing its non-carcinogenic character.

Lomefloxacin

Lomefloxacin is a second-generation difluorinated broad-spectrum quinolone antibiotic. It is used for the treatment of bronchitis, urinary tract infection, conjunctivitis, otitis externa, and otitis media. A comprehensive profile was performed on lomefloxacin including nomenclature, formulae, elemental composition appearance, and physical characteristics. Spectral methods including ultraviolet spectrum, vibrational spectrum, ¹H and ¹³C nuclear magnetic resonance one- and two-dimensional spectra, and mass spectrum were used for both identification and analysis of the drug. The profile also contains the reported methods of analysis such as voltammetric, polarographic, spectrophotometric, fluorimetric, chromatographic, capillary electrophoresis, and immunoassay methods. In addition, the uses, pharmacokinetics, and chemical synthesis of lomefloxacin are described.

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.

Enantioseparation of lomefloxacin hydrochloride by high-speed counter-current chromatography using sulfated-β-cyclodextrin as a chiral selector

Enantiomers of lomefloxacin hydrochloride were separated by high-speed counter-current chromatography (HSCCC) using sulfated-β-cyclodextrin as a chiral selector (CS). The separation was performed with a two-phase solvent system composed of ethyl acetate-methanol-water (10:1:10, v/v) containing CS at 0-60mmol/l in a head-to-tail elution mode, while obtained fractions were identified by polarimeter and spectropolarimeter. The results show that the concentration of the CS in the system strongly affects the peak resolution (Rs). As the concentration of CS increases, the Rs first increases reaching the maximum at 50mmol/l and then decreases. When the CS concentration is kept constant in the solvent systems, the Rs decreases as the concentration of the lomefloxacin hydrochloride increases. The overall results of our studies indicated that sulfated-β-cyclodextrin is very useful for the chiral separation by HSCCC.

Quinolone pharmacokinetics

Fluoroquinolones have broad antibacterial spectra and are active against most Gram-negative and many Gram-positive species. They exhibit excellent oral bioavailability, extensive tissue penetration, low protein binding, and a long elimination half-life. This review compares and contrasts the pharmakonetics of some quinolone antibiotics - especially pefloxacin, ciprofloxacin, enoxacin, norfloxacin, ofloxacin, fleroxacin and lomefloxacin - in terms of their adsorption, distribution, metabolism, elimination, and interactions with other drugs and with food. In addition, the pharmacokinetics of these agents in the elderly and in patients with renal or hepatic impairment is discussed. The fluoroquinolones are established as a major class of antibiotics in the treatment of infections but pharmacokinetics factors should be considered when deciding on the most appropriate of these agents to use in individual patients.

Antibiotic treatment in patients with altered pathophysiological pathways

The pharmacokinetics of antibiotics are reviewed under particular physiological (senescence) and pathological (renal failure, liver failure) conditions. As regards the antibiotic management in the elderly, the main problems are related to the "immunosenescence" and to kinetic modifications, occurring even in the absence of an evident renal impairment. If manifest renal failure is present, the main issue is the correct dosage, and a careful consideration of the interest of the patient when they have to undergo hemodialysis. In cases of liver failure, a number of factors impairing the kinetics of antibiotics are discussed, underlining how these are too often underestimated in therapeutical approaches. The paper is focused on the behavior of new molecules, with particular regard to Teicoplanin, Carbapenems and Fluoroquinolones.

Highly sensitive spectrofluorimetric determination of lomefloxacin in spiked human plasma, urine and pharmaceutical preparations

A sensitive, simple and selective spectrofluorimetric method was developed for the determination of lomefloxacin in biological fluids and pharmaceutical preparations. The method is based on the reaction between the drug and 4-chloro-7-nitrobenzodioxazole in borate buffer of pH 8.5 to yield a highly fluorescent derivative that is measured at 533 nm after excitation at 433 nm. The calibration curves were linear over the concentration ranges of 12.5-625, 15-1500 and 20-2000 ng/mL for plasma, urine and standard solution, respectively. The limits of detection were 4.0 ng/mL in plasma, 5.0 ng/mL in urine and 7.0 ng/mL in standard solution. The intra-assay accuracy and precision in plasma ranged from 0.032 to 2.40% and 0.23 to 0.36%, respectively, while inter-assay accuracy and precision ranged from 0.45 to 2.10% and 0.25 to 0.38%, respectively. The intra-assay accuracy and precision estimated on spiked samples in urine ranged from 1.27 to 4.20% and 0.12 to 0.24%, respectively, while inter-assay accuracy and precision ranged from 1.60 to 4.00% and 0.14 to 0.25%, respectively. The mean recovery of lomefloxacin from plasma and urine was 98.34 and 98.43%, respectively. The method was successfully applied to the determination of lomefloxacin in pharmaceuticals and biological fluids.

Postoperative lomefloxacin 0.3% prophylaxis in strabismus surgery

PURPOSE

To evaluate the efficacy of topical lomefloxacin 0.3% versus chloramphenicol 0.2% with polymyxin B 2500 U/ml in the treatment of patients after strabismus surgery.

METHODS

Seventy-nine consecutive patients who underwent strabismus surgery from April through October 2006 were randomized to receive topical lomefloxacin 0.3% (n = 45, 58 eyes) or chloramphenicol 0.2% with polymyxin B 2500 U/ml (n = 34, 40 eyes) postoperatively, in addition to topical dexamethasone 0.1% and diclophenac 0.1%. The groups were compared for clinical signs of local cellulitis and findings on conjunctival cultures.

RESULTS

From postoperative day 1 to day 28, rates of chemosis decreased from 96% to 9.5% in the lomefloxacin group and from 94% to zero in the chloramphenicol group; rates of hyperemia decreased from 100% to zero in both groups. Accordingly, rates of a cumulative clinical sign score (CCSS) decreased from 60% to zero in the lomefloxacin group and 50% to zero in the chloramphenicol group. Rates of positive bacterial cultures dropped from 59.6% preoperatively to 48.3% on day 14 in the lomefloxacin group and from 63% to 47% in the chloramphenicol group.

CONCLUSIONS

Topical lomefloxacin is a potent alternative to topical chloramphenicol eye drops after strabismus surgery for the control of pain, infection and discharge, chemosis, hyperemia, and conjunctival hemorrhage.

Determination of bioequivalence of lomefloxacin tablets using urinary excretion data

The present study describes development of a sensitive and simple HPTLC method for estimation of lomefloxacin (LMF) in human urine. The drug was extracted using chloroform after adjusting the pH of urine to 7.0. Chloroform extract was spotted on silica gel 60 F(254) TLC plate and was developed in a mixture of n-butanol-methanol-ethyl acetate-6 M ammonia (4:2:3:2, v/v/v/v) as the mobile phase and scanned at 290 nm. The peak for LMF resolved at R(F) of 0.40+/-0.02. The method was validated in terms of linearity (50-600 microgram/ml), precision, specificity and accuracy. The limit of detection and limit of quantification for LMF in urine were found to be 20 and 50 microgram/ml, respectively. The average recovery of LMF from urine was 91.93%. The proposed method was applied to generate urinary excretion data for LMF after administration of two market LMF tablet formulations (400 mg, Formulation R and Formulation T) to six healthy human volunteers in a two-treatment, open, crossover design. Various pharmacokinetic parameters like peak excretion rate ((dAU/dt)(max)), time for peak excretion rate (t(max)), AUC(0-48), AUC(0- infinity ), cumulative amount and % cumulative amount of LMF excreted, elimination half-life (t(1/2)), terminal elimination rate constant (k(el)) and overall elimination rate constant (K), were calculated for both the formulations. The average cumulative amounts of LMF excreted in urine after administration of Formulation R and Formulation T were found to be 321.60 mg (80.40% of dose) and 296.51 mg (74.13% of dose), respectively. The urinary excretion profiles of LMF upto 48 h for both the formulations were found to be similar. Statistical comparison (90% confidence intervals of ratio) of various pharmacokinetic parameters of Formulation T with that of Formulation R revealed that Formulation T is bioequivalent with Formulation R.

Safety of fluoroquinolones: An update

The fluoroquinolone class of antimicrobials has been in clinical use for over 13 years. During that period, some representatives of the class have been extensively prescribed, such as ciprofloxacin and levofloxacin, while others have seen minimal use and have been restricted or withdrawn, namely, trovafloxacin and grepafloxacin. Manipulation of the fluoroquinolone structure by substituting a range of moieties around the core has yielded enhanced antibacterial activity, but in some cases this has come at a price. Specific substitutions are discussed in relation to particular recognized adverse events. In the present paper, newly introduced fluoroquinolones, such as moxifloxacin and gatifloxacin, are examined in terms of anticipated class effects and recent clinical experience. These antimicrobials are associated with reactions such as diarrhea, nausea, headache and other typical antimicrobial phenomena at rates less than 5%. New fluoroquinolone agents should be examined carefully in light of structural findings until adequate clinical data are amassed.

Pulmonary disposition of lomefloxacin in patients with acute exacerbation of chronic obstructive pulmonary disease. A multiple-dose study

In this study we have measured the concentrations of lomefloxacin at steady state in serum and in the intrapulmonary region at specified intervals for 24 h following administration of the last dose of drug in patients suffering from acute exacerbation of chronic obstructive pulmonary disease (COPD). Twenty subjects were enrolled. They received lomefloxacin 400 mg orally once-daily for 5 consecutive days. All patients were divided into five groups, with 4 subjects in each group, according to sampling times (2, 4, 8, 12, and 24 h after the last dose). At bronchoscopy, bronchial biopsies and bronchoalveolar lavage (BAL) were performed. At 12 h after the last dose, serum concentration of lomefloxacin was >1.0 microg/mL and at 24 h it was still detectable, but, at all times, the concentrations in bronchial secretion, bronchial mucosa, and epithelial lining fluid (ELF) were greater than the concentrations in serum [bronchial secretions (pg/mL) = 2.5+/-1.2; 2.2+/-1.0: 2.0+/-1.1; 1.8+/-1.1; 0.6+/-0.3. bronchial mucosa (microg/g) = 5.9+/-2.1; 6.2+/-1.8; 2.6+/-2.2; 1.9+/-1.5; 1.0+/-0.9. ELF (microg/mL) = 6.9+/-2.8; 5.9+/-2.6; 3.1+/-1.9; 2.2+/-1.0; 0.8+/-1.3. serum (microg/mL) = 3.2+/-1.4; 2.8+/-0.9: 2.1+/-1.5; 1.2+/-1.1; 0.4+/-0.81. We must stress that we observed a large inter-individual variability in concentrations. Our data show that lomefloxacin once-daily induces high and sustained concentrations in the various potential sites of pulmonary infection and clearly indicate that the pharmacokinetic behavior of this fluoroquinolone permits once-daily administration in patients with acute exacerbations of COPD.

Ocular distribution of lomefloxacin 0.3% after a single instillation in the infected eye of pigmented rabbits

We investigated the distribution of lomefloxacin, a fluoroquinolone, in the infected eye of pigmented rabbits after one instillation of 50 microliters lomefloxacin 0.3% eye drop, and compared tissue concentrations with therapeutic levels. Infection was induced by 6 instillations of Pseudomonas aeruginosa inoculum 6 x 10(5) bacteria) on centrally scratched cornea of 32 pigmented rabbits. Fifty microliters of 14[C] lomefloxacin 0.3% were instilled 24 hours after infection and animals were sacrificed 0.25, 0.5, 1, 2, 4, 8 and 12 hours later. Ocular structures, tear fluid, whole blood and plasma were then sampled, and tissue levels over time, Tmax, Cmax and area under the curve (AUC) were calculated. Lomefloxacin rapidly penetrated into the ocular structures: tear (Tmax 0.25 hours, Cmax 366 micrograms/ml, AUC 360 micrograms/ml x hour), corresponding value were for: eye lids (0.25, 7, 33), conjunctiva (0.25, 11, 7), cornea (0.25, 56, 70), aqueous humor (1, 8, 14), iris ciliary-body (4, 34, 252), lens (1, 0.2, 0.6). Tear levels remained high for many hours and were 34, 48, 1 and 27 micrograms/ml at 1, 2, 4 and 8 hours following a single instillation. Elimination from ocular structures was rapid. Therapeutic levels were achieved after a single instillation (mainly in the external ocular structures) when compared with MIC 90% values (1-10 micrograms/ml).

Proposed mechanism for the photodynamic generation of 8-oxo-7,8-dihydro-2'-deoxyguanosine produced in cultured cells by exposure to lomefloxacin

In this study, lomefloxacin (LMX), a widely used quinolone antibiotic with a high frequency of clinical phototoxicity, was investigated by measuring the effects of several antioxidants on its ability to form of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG) in cultured adult rat liver cells after exposure to UVA. In the current study the observed DNA damage, reflected by the formation of 8-oxo-dG, was almost completely inhibited by co-incubation of LMX and cultured cells with sodium azide (NaN3) that specifically quenches singlet oxygen. Vitamin E (alpha-tocopherol), known to quench both superoxide and singlet oxygen, inhibited 8-oxo-dG formation by approximately 54%. Mannitol, a hydroxyl radical scavenger, inhibited 8-oxo-dG formation by 64%. Butylated hydroxyanisole (BHA), a scavenger of hydroxyl, peroxy and alkoxy radicals, showed no inhibition of 8-oxo-dG formation but in fact enhanced levels of 8-oxo-dG by 169%. The results of this study suggest that the mechanism for the photodynamic generation of 8-oxo-dG by LMX is mediated, at least in part, by both singlet oxygen and hydroxyl radical and involves both type I and type II photosensitization.

A fluoroquinolone antibiotic with a methoxy group at the 8 position yields reduced generation of 8-oxo-7,8-dihydro-2'-deoxyguanosine after ultraviolet-A irradiation

We have previously reported that two fluoroquinolone antibiotics gave rise to 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG) in DNA of cells concurrently exposed to UV-A and that this correlated with clinical phototoxicity. To determine the structural basis for generation of oxidative damage, the ability of two synthetic fluoroquinolone candidate antibiotics, Bayer 12-8039 (12-8039) and Bayer Y3118 (Y3118), to give rise to 8-oxo-dG in cultured liver epithelial cells was compared. 12-8039 contains a methoxy group at the 8 position of the quinolone nucleus, whereas Y3118 contains a chlorine group at the same position. Y3118 produced dose-dependent increases in 8-oxo-dG formation in cultured cells after UVA irradiation, whereas the 8-OCH3-substituted 12-8039 produced no increase. Also, after exposure to 20 J/cm2 UVA, UV spectral scans of both compounds revealed that Y3118 underwent photodegradation whereas 12-8039 was stable. These results demonstrate that the presence of an 8-OCH3 group on the quinolone nucleus is important for the reduction of photogeneration of oxidative DNA damage and photodegradation in the presence of UVA irradiation. From this, we suggest that 12-8039 has little phototoxic potential.

The synthesis of fluorine-18 lomefloxacin and its preliminary use in human studies

Lomefloxacin is a new fluorine-containing antibiotic that has recently been approved for general use. Fluorine-18 lomefloxacin has been prepared by fluoride exchange between fluorine-18 fluoride and lomefloxacin in DMSO. Both time and temperature of the reaction have been optimized and conditions developed for the isolation and purification of the labeled product in a form suitable for oral administration. The exchange reaction provides sufficient labeled material for human studies with pharmacologically relevant quantities of the drug. We have performed preliminary human studies with this compound using positron emission tomography to estimate the tissue distribution of the compound and show the distribution of the compound into the liver and lungs.

Antibiotic use in the emergency department. III. The quinolones, new beta lactams, beta lactam combination agents, and miscellaneous antibiotics

This article reviews several new, relatively broad-spectrum antibiotics that have utility in the emergency department (ED). The quinolones have excellent activity against gram-negative organisms, including gonococcus, and are characterized by very high bioavailability after oral administration. The new beta-lactams aztreonam and imipenem have broad spectra but limited usefulness to the emergency physician, and should be reserved for judicious use in severe infections, particularly those involving Pseudomonas. Clavulanate, sulbactam, and tazobactam are themselves antimicrobials that have been combined with beta-lactams such as ampicillin and ticarcillin to produce agents with significant potential utility in the ED; these are typically not first-line agents, however, and their use should be governed by both clinical and cost concerns. Finally, three older antibiotics--vancomycin, metronidazole, and clindamycin--are reviewed with respect to updated indications for their use in the ED.

Multi-center validation of proposed disk diffusion susceptibility testing interpretive criteria for lomefloxacin using more than 1,500 clinical isolates

The accuracy of disk diffusion susceptibility testing of lomefloxacin was evaluated using 1,555 recent clinical isolates from ten medical centers. The isolates were rapidly growing nonfastidious aerobic species (1,501 isolates) and Haemophilus species (54 isolates), each found as an indicated species in the product package insert. Applying the recently proposed modification of disk diffusion interpretive criteria (susceptible at > or = 20 mm and resistant at < or = 16 mm), absolute categorical agreement for nonfastidious aerobes (1,501 strains) was 95.5% with 0.5% very major and 0.1% major errors (error rates calculated using all tested strains as the denominator). The intermethod discord (MIC vs disk diffusion) was 0.5%. This contrasts to the current NCCLS recommended criteria (susceptible at > or = 22 mm and resistant at < or = 18 mm) where the absolute categorical agreement was significantly less (89.6%) with 0.2% very major, and 0.3% major errors, and the intermethod discord was 7.1%. For Haemophilus species (54 strains), intermethod agreement was complete using either the current NCCLS interpretive criteria or the modified criteria. These multicenter (ten laboratories) data support the acceptance of the proposed modification of disk diffusion interpretive criteria for 10-microgram lomefloxacin disks.

Reevaluations of disk diffusion susceptibility testing interpretive criteria for lomefloxacin and norfloxacin using fluoroquinolone-resistant isolates

The current National Committee for Clinical Laboratory Standards interpretive criteria for disk diffusion susceptibility testing of lomefloxacin and norfloxacin were reevaluated using a test panel of 298 bacteria (200 with ciprofloxacin minimum inhibitory concentrations (MICs) at > or = 4 micrograms/ml). MICs were correlated with the diameter of zones of inhibition by regression statistics and error-rate bounding methods. Modifications of the interpretive criteria for lomefloxacin disk susceptibility testing are proposed as follows: susceptible at > or = 20 mm and resistant at < or = 16 mm, a 2-mm decrease of existing break-point zones. These criteria result in an absolute interpretive agreement of 95.3% with a very major (false susceptible) error rate of only 0.7%. The currently used criteria for norfloxacin (susceptible at > or = 16 mm and resistant at < or = 13 mm) were validated, and these break-points had an absolute interpretive correlation between methods of 91.9%. The change proposed for lomefloxacin disk interpretations would minimize minor and major errors most often reported for Staphylococcus saprophyticus isolates.

Update of lomefloxacin in vitro activity and spectrum. A multicenter trial testing contemporary pathogens following Food and Drug Administration validation guidelines. Lomefloxacin Activity Study Group

The United States Food and Drug Administration recently recommended that the antimicrobial product package insert (PPI) subsection on microbiology be annually validated with regard to the compound's spectrum and potency. To address this request, a nine-laboratory trial was organized to test (two methods) lomefloxacin, a newer fluoroquinolone, and nine comparison drugs against PPI-listed pathogens (1934 strains). A broad geographic sampling (nine medical centers) was achieved, and lomefloxacin was determined to be active [minimum inhibitory concentration (MICs), < or = 2 micrograms/ml for > or = 90% of strains] for all PPI-listed species except Pseudomonas aeruginosa, Citrobacter freundii, and Providencia rettgeri (42%-87% inhibited). Comparison fluoroquinolones also had a similarly compromised spectrum of activity against these species. Additional organism species, including Neisseria gonorrhoeae, N. meningitidis, Salmonella enteriditis, and Shigella species, should be added to the lomefloxacin PPI (MIC90s, 0.03-0.25 microgram/ml) following data generated in this study. These in vitro results indicate that lomefloxacin remains active against the vast majority of clinically "indicated" species, and that it has a spectrum compatible with other marketed fluoroquinolones for these tested pathogens, monitored in 1994.

Effect of seven fluoroquinolones on the determination of serum creatinine by the picric acid and enzymatic methods

OBJECTIVE

To investigate in vitro the interaction of seven fluoroquinolone antibiotics with the determination of serum creatinine by the picric acid and enzymatic methods.

DESIGN

This blind, in vitro study assayed duplicate serum samples for creatinine by the picric acid and enzymatic methods with averaged spiked concentrations of 2.71, 13.56, 27.12, and 108.47 mumol/L of ciprofloxacin, fleroxacin, lomefloxacin, ofloxacin, 1-ofloxacin, sparfloxacin, and temafloxacin. Cefoxitin (in concentrations of 233.9, 1169.6, 1754.4, and 2339.2 mumol/L) was used as a positive control for the picric acid assay.

SETTING

University-affiliated hospital, Department of Pharmaceutical Services and Clinical Chemistry section of the Department of Pathology.

MAIN OUTCOME MEASURE

The serum creatinine samples spiked with the seven substituted fluoroquinolones and cefoxitin were assayed by both the picric acid and enzymatic assays. Statistical analysis compared the spiked samples with blank serum by Student's t-test and concentration ranges were compared by analysis of variance. A statistically significant interference with serum creatinine was p < 0.05.

RESULTS

None of the substituted fluoroquinolones interfered significantly with the determination of serum creatinine by either method. Cefoxitin significantly interfered with the determination of serum creatinine by the picric acid method.

CONCLUSIONS

Fluoroquinolones do not interfere with the determination of serum creatinine by either the picric acid or enzymatic method.

Safety and efficacy of lomefloxacin versus norfloxacin in the treatment of complicated urinary tract infections

Seventy patients with complicated urinary tract infections were treated with either lomefloxacin (400 mg once daily) or norfloxacin (400 mg twice daily) for 10 to 14 days. A total of 19 (86%) of 22 patients treated with lomefloxacin and 20 (74%) of 27 patients treated with norfloxacin were cured, as defined by a negative culture five to nine days after completion of therapy (p = 0.09). After four to six weeks, the figures were 56% for lomefloxacin and 48% for norfloxacin. Adverse effects in the lomefloxacin group were observed on 20 occasions in 12 patients (one stopped treatment) compared to nine occasions in five patients treated with norfloxacin (difference not significant).

Steady-state pharmacokinetics and sputum penetration of lomefloxacin in patients with chronic obstructive pulmonary disease and acute respiratory tract infections

Oral doses of 400 mg of lomefloxacin were administered once daily prior to breakfast to 10 middle-aged to elderly hospitalized patients with chronic obstructive pulmonary disease during treatment for bronchopulmonary infections. Serial plasma and sputum samples and fractional urine samples were obtained over a steady-state dosing interval. Lomefloxacin concentrations were determined in duplicate by a validated agar well diffusion microbiological assay. The maximum plasma lomefloxacin concentration (4.5 +/- 1.8 mg/liter), the time of occurrence of the maximum concentration (1.7 +/- 1.6 h), and the apparent volume of distribution associated with the terminal phase (2.19 +/- 1.05 liter/kg) were comparable to the values reported for healthy, young volunteers. Compared with the data reported for young adults, the elimination half-life (12.7 +/- 4.67 h) was longer and the apparent total body clearance (132 +/- 36.6 ml/min/1.73 m2) was lower in middle-aged to elderly patients. These differences were most likely attributable to age-related decreases in renal function, as evidenced by the lower lomefloxacin renal clearance (70.3 +/- 33.5 ml/min) in patients. The presence of acute respiratory infection per se did not appear to alter lomefloxacin pharmacokinetics. The peak lomefloxacin concentration in purulent, expectorated sputum samples of 4.3 +/- 1.2 mg/liter occurred 3.1 +/- 1.7 h after dose administration and subsequently declined to 1.7 +/- 0.5 mg/liter at the end of the 24-h dosing interval. The percent penetration into sputum, as assessed by comparing the area under the curve for sputum and plasma samples, was 120 +/- 39.8 (range, 70 to 185). The steady-state lomefloxacin concentrations in plasma and sputum samples from ill, older patients were in excess of the MICs for 90% of the strains tested of common, susceptible respiratory pathogens over most of the dosing interval.

Uncomplicated urinary tract infections: lomefloxacin versus trimethoprim/sulphamethoxazole

Data were collected from 14 French centres which participated in a randomized study to compare the safety and efficacy of 400 mg lomefloxacin taken orally once daily by 62 patients with 160/800 mg trimethoprim/sulphamethoxazole (TMP/SMX) taken orally twice daily by 64 patients with uncomplicated urinary tract infections. Most patients were infected with Escherichia coli at baseline (72.4% in the lomefloxacin group and 69.0% in the TMP/SMX group) and all patients were treated for 5 days. At 5-9 days post-treatment, lomefloxacin had eradicated the causative organism of infection in 100% of evaluable patients treated with lomefloxacin compared with 86.7% of those treated with TMP/SMX. At 4-6 weeks post-treatment, there were no marked differences in eradication rates between the two treatment groups: 83.3% and 80.0% for the lomefloxacin and TMP/SMX groups, respectively. Clinical cure rates showed no marked differences between treatment groups at 5-9 days or at 4-6 weeks post-treatment. At 5-9 days post-treatment, lomefloxacin achieved a clinical cure rate of 78.6% compared with 86.7% for TMP/SMX evaluable patients. At 4-6 weeks post-treatment, the clinical cure rates were 66.7% and 86.7% for the evaluable lomefloxacin- and TMP/SMX-treated patients, respectively. Both treatment regimens were well tolerated with a low incidence of adverse events. In conclusion, once-daily oral dosing with lomefloxacin is a safe and efficacious alternative to twice-daily dosing with TMP/SMX in the treatment of uncomplicated urinary tract infections.