Oral bioavailability of trovafloxacin with and without food in healthy volunteers

Quinolones as a Potential Drug in Genitourinary Cancer Treatment-A Literature Review

Quinolones, broad-spectrum antibiotics, are frequently prescribed by urologists for many urological disorders. The mechanism of their bactericidal activity is based on the inhibition of topoisomerase II or IV complex with DNA, which consequently leads to cell death. It has been observed that these antibiotics also act against the analogous enzymes present in eukaryotic cells. Due to their higher accumulation in urine and prostate tissue than in serum, these drugs seem to be ideal candidates for application in genitourinary cancer treatment. In this study, an extensive literature review has been performed to collect information about concentrations achievable in urine and prostate tissue together with information about anticancer properties of 15 quinolones. Special attention was paid to the application of cytotoxic properties of quinolones for bladder and prostate cancer cell lines. Data available in the literature showed promising properties of quinolones, especially in the case of urinary bladder cancer treatment. In the case of prostate cancer, due to low concentrations of quinolones achievable in prostate tissue, combination therapy with other chemotherapeutics or another method of drug administration is necessary.

Design and synthesis of an oral prodrug alalevonadifloxacin for the treatment of MRSA infection

Levonadifloxacin is a parenteral anti-MRSA benzoquinolizine antibacterial drug recently launched as, EMROK in India to treat acute bacterial skin and skin structure infections (ABSSSI) in hospitalized patients. As a step down therapy an oral form of levonadifloxacin with comparable PK/PD was needed because the levonadifloxacin exhibits very poor oral absorption. To improve the drugability in terms of oral absorption a pro-drug approach was evaluated. Structurally levonadifloxacin provides two sites amenable for ester or amide formation, a carboxyl function of benzoquinolizine pharmacophore and hydroxyl group on piperidine side chain. Several aliphatic, aromatic and amino acid esters of C-2 carboxylic acid, C-4-hydroxyl piperidine and double esters at both C-2, C-4 positions were synthesized. The cleavage of prodrugs was studied in vitro as well as in animal models to access their suitability as prodrug function. Among C-2 carboxylic ester prodrugs, daloxate (WCK 2320) showed highest cleavage in serum as well as in liver enzyme; however its stability in aqueous solution was unfavorable. In contrast, most of the esters at the hydroxyl group like propionyl ester (WCK 2305) and amino acid esters such as l-alanine (WCK 2349), l-valine (WCK 2630) were cleaved readily releasing active drug. Thus, indicating C-4-hydroxyl piperidine was amenable site for enzymatic cleavage over esters of C-2 carboxylic acid. Additionally, amino acid esters provided an opportunity to make salt, facilitating improved aqueous solubility. Methanesulfonate salt of l-alanine ester of levonadifloxacin (WCK 2349) was successfully developed and launched as oral prodrug alalevonadifloxacin (EMROK-O).

Pharmacokinetics and Pharmacodynamics of the New Quinolones

In this review, the authors describe the pharmacokinetic (PK) and pharmacodynamic (PD) characteristics of the new quinolones (levofloxacin, gatifloxacin, moxifloxacin, gemifloxacin, and garenoxacin) and discuss their implications on adequate therapy of patients with respiratory infections. The newer quinolones display excellent bioavailability and have longer serum half-lives than ciprofloxacin. In addition, they have the ability to concentrate in respiratory tract tissues and fluids at levels that exceed serum-drug concentrations. Also, the newer quinolones exhibit broad-spectrum activity against both susceptible and resistant organisms. Those favorable PK/PD properties make the new quinolones an attractive therapeutic alternative to traditional agents for common respiratory infections. Understanding the PK/PD of quinolone antibiotics can facilitate selection of optimal regimens to hasten response, prevent treatment failures, and minimize the development of resistance.

Fluoroquinolones in paediatrics

Fluoroquinolones have a broad spectrum of activity against gram-positive, gram-negative, and mycobacterial organisms as well as anaerobes, Mycoplasma, Chlamydia, Ureaplasma, and Legionella spp. They have excellent oral bioavailability, with good tissue penetration, and long elimination half-lives. The experience with fluoroquinolones in paediatrics has been limited because of concerns about arthropathy, based on findings in animal models. However, there has not been a definitive fluoroquinolone-associated case of arthropathy described in the literature. We believe that there are a number of specific paediatric infections in which the clinical efficacy and tolerability of the fluoroquinolones should be further investigated. These include patients with cystic fibrosis who have repeated infections with Pseudomonas spp., patients with pseudomonal and other gram-negative infections such as urinary tract infections and osteomyelitis, and febrile neutropenic patients. Meningeal infections caused by multiple drug-resistant Streptococcus pneumoniae and gram-negative organisms, gastroenteritis due to enteric pathogens, and mycobacterial infections are other potential conditions where fluoroquinolones should be studied in paediatric patients.

Comparative in vitro activity and pharmacodynamics of five fluoroquinolones against clinical isolates of Streptococcus pneumoniae

STUDY OBJECTIVE

To compare in vitro activity and pharmacodynamics of five fluoroquinolones against clinical isolates of Streptococcus pneumoniae.

DESIGN

In vitro analysis.

SETTING

University research laboratory.

INTERVENTION

Minimum inhibitory concentrations (MICs) were determined for penicillin and five fluoroquinolones by E test for 201 S. pneumoniae isolates. Serum concentration-time profiles were simulated for the following regimens: ciprofloxacin 750 mg orally every 12 hours and 400 mg intravenously every 8 hours; levofloxacin 500 mg orally and intravenously every 24 hours; trovafloxacin 200 mg orally and intravenously every 24 hours; gatifloxacin 400 mg orally and intravenously every 24 hours; and clinafloxacin 200 mg orally and intravenously every 12 hours.

MEASUREMENTS AND MAIN RESULTS

Free 24-hour areas under the serum concentration-time curves (AUC0-24) were calculated using the trapezoidal rule, and the average AUC0-24:MIC ratio was calculated for each regimen. Differences in ratios among agents were determined by analysis of variance (Scheffe post hoc test, p < 0.05). For intravenous dosing, the average AUC0-24:MIC for gatifloxacin, clinafloxacin, trovafloxacin, ciprofloxacin, and levofloxacin was 146, 142, 122, 71, and 61, respectively. For both oral and intravenous regimens, gatifloxacin and clinafloxacin ratios were significantly greater than those for trovafloxacin, levofloxacin, and ciprofloxacin (p < or = 0.007). Ratios for trovafloxacin were significantly greater than those for levofloxacin and ciprofloxacin (p < 0.0001), and levofloxacin and ciprofloxacin ratios were not significantly different from each other.

CONCLUSION

Gatifloxacin and clinafloxacin achieve significantly higher AUC0-24:MIC ratios for S. pneumoniae than trovafloxacin, levofloxacin, and ciprofloxacin. Large comparative studies are necessary to determine the clinical significance of these findings.

Comparative pharmacokinetics of ciprofloxacin, gatifloxacin, grepafloxacin, levofloxacin, trovafloxacin, and moxifloxacin after single oral administration in healthy volunteers

In an open, randomized, six-period crossover study, the pharmacokinetics of ciprofloxacin, gatifloxacin, grepafloxacin, levofloxacin, moxifloxacin, and trovafloxacin were compared after a single oral dose in 12 healthy volunteers (6 men and 6 women). The volunteers received 250 mg of ciprofloxacin, 400 mg of gatifloxacin, 600 mg of grepafloxacin, 500 mg of levofloxacin, 400 mg of moxifloxacin, and 200 mg of trovafloxacin. The concentrations of the six fluoroquinolones in serum and urine were measured by a validated high-performance liquid chromatography method. Blood and urine samples were collected before and at different time points up to 48 h after medication. Levofloxacin had the highest peak concentration (C(max), in micrograms per milliliter) (6.21+/-1.34), followed by moxifloxacin (4.34+/-1.61) and gatifloxacin (3.42+/-0.74). Elimination half-lives ranged from 12.12+/-3.93 h (grepafloxacin) to 5.37+/-0.82 h (ciprofloxacin). The total areas under the curve (AUC(tot), in microgram-hours per milliliter) for levofloxacin (44.8+/-4.4), moxifloxacin (39.3+/-5.35), and gatifloxacin (30+/-3.8) were significantly higher than that for ciprofloxacin (5.75+/-1.25). Calculated from a normalized dose of 200 mg, the highest C(max)s (in micrograms per milliliter) were observed for levofloxacin (2.48 +/-0.53), followed by moxifloxacin (2.17+/-0.81) and trovafloxacin (2.09+/-0.58). The highest AUC(tot) (in microgram-hours per milliliter) for a 200-mg dose were observed for moxifloxacin (19.7+/-2.67) and trovafloxacin (19.5+/-3.1); the lowest was observed for ciprofloxacin (4.6+/-1.0). No serious adverse event was observed during the study period. The five recently developed fluoroquinolones (gatifloxacin, grepafloxacin, levofloxacin, moxifloxacin, and trovafloxacin) showed greater bioavailability, longer half-lives, and higher C(max)s than ciprofloxacin.

Inhibitory effects of the quinolone antibiotics trovafloxacin, ciprofloxacin, and levofloxacin on osteoblastic cells in vitro

We studied the inhibitory effects of the fluoroquinolones levofloxacin, ciprofloxacin, and trovafloxacin on growth and extracellular matrix mineralization in MC3T3-E1 osteoblast-like cell cultures. Levofloxacin had the least inhibitory effect on cell growth, with a 50% inhibitory concentration of approximately 80 microg/ml at 48 and 72 hours. Ciprofloxacin had an intermediate degree of inhibition, with a 50% inhibitory concentration of 40 microg/ml at 48 and 72 hours. Trovafloxacin exerted a profound inhibitory effect on cell growth, with a 50% inhibitory concentration of 0.5 microg/ml, lower than clinically achievable serum levels. The decreased cell counts with up to 2.5 microg/ml of trovafloxacin and with up to 40 microg/ml of ciprofloxacin were not associated with decreased rates of 5-bromo-2'-deoxyuridine incorporation per cell. Alatrovafloxacin, the L-alanyl-l-alanine prodrug of trovafloxacin, exerted effects on proliferation and 5-bromo-2'-deoxyuridine incorporation similar to those of the parent compound. The quinolones evaluated also inhibited extracellular matrix mineralization by MC3T3-E1 cells. Treatment of confluent cultures with trovafloxacin, ciprofloxacin, or levofloxacin resulted in strong inhibition of calcium deposition, as determined on day 14 by alizarin red staining and biochemical analysis. The effect was apparent with 2.5-5 microg/ml of each of the three antibiotics tested and progressively increased to more than a 90% decline in the calcium/protein ratio with 20-40 microg/ml antibiotic concentration. Further in vivo studies are advocated to evaluate the relevance of the in vitro cytotoxicity reported here to bone healing in orthopaedic patients.

The effect of food on the bioavailability of oral gemifloxacin in healthy volunteers

The effect of food on the bioavailability of gemifloxacin was investigated at two doses (320 and 640 mg) in healthy male and female volunteers. A total of 21 subjects entered the open label, four-period crossover study. Each subject received single oral doses of 320 and 640 mg in the fasted state and after a high fat meal, on separate dosing occasions in a randomised fashion. There was on average, a 3% (95% CI (0.88, 1.07)) and 12% (95% CI (0.79, 0.97)) reduction in AUC and a 12% (95% CI (0.76, 1.02) and 14% (0.75, 1.00) reduction in Cmax after the 320- and 640-mg doses, respectively. The results indicate a minor effect of food on bioavailability of gemifloxacin (320 and 640 mg). Such a reduction in systemic exposure would be considered to be not clinically relevant. Tmax data were inconclusive but indicated a possible slight delay in Tmax of, on average, 0.75 and 0.21 h after the 320- and 640-mg doses, respectively. Delays of this magnitude in reaching maximum concentrations are unlikely to be of clinical importance for an antibiotic drug. Both 320 and 640 mg gemifloxacin were well tolerated in fed and fasted states by healthy volunteers. It can be concluded therefore, that gemifloxacin can be taken with and without food.

Pharmacokinetics of a fluoronaphthyridone, trovafloxacin (CP 99,219), in infants and children following administration of a single intravenous dose of alatrofloxacin

The pharmacokinetics of trovafloxacin following administration of a single intravenous dose of alatrofloxacin, equivalent to 4 mg of trovafloxacin per kg of body weight, were determined in 6 infants (ages 3 to 12 months) and 14 children (ages, 2 to 12 years). There was rapid conversion of alatrofloxacin to trovafloxacin, with an average +/- standard deviation (SD) peak trovafloxacin concentration determined at the end of the infusion of 4.3 +/- 1.4 microg/ml. The primary pharmacokinetic parameters (average +/- SD) analyzed were volume of distribution at steady state (1.6 +/- 0.6 liters/kg), clearance (151 +/- 82 ml/h/kg), and half-life (9.8 +/- 2.9 h). The drug was well tolerated by all children. There were no age-related differences in any of the pharmacokinetic parameters studied. Less than 5% of the administered dose was excreted in the urine over 24 h. On the basis of the mean area under the concentration-time curve of 30.5 +/- 10.1 microg. h/ml and the susceptibility (< or =0.5 microg/ml) of common pediatric bacterial pathogens to trovafloxacin, dosing of 4 mg/kg/day once or twice daily should be appropriate.

Oral bioavailability and pharmacokinetics of trovafloxacin in patients with AIDS

Trovafloxacin pharmacokinetics were evaluated in 12 subjects with AIDS. By using a randomized design, single 200-mg doses of oral trovafloxacin and intravenous alatrofloxacin were administered. The mean absolute bioavailability was 91%. The pharmacokinetics of trovafloxacin when administered orally as the active form or intravenously as the prodrug (alatrofloxacin) are not altered in subjects with AIDS compared to those in healthy adults.

Effects of food on the pharmacokinetics of sparfloxacin

Sparfloxacin, a fluoroquinolone with a broad antimicrobial spectrum and long elimination half-life, is indicated for the treatment of community-acquired pneumonia and acute bacterial exacerbations of chronic bronchitis in adult patients. The present study was undertaken to determine the effects of skim milk and a high-fat breakfast without milk on the single-dose pharmacokinetic characteristics of this antibiotic. The pharmacokinetics of a single 200-mg dose of sparfloxacin were assessed in a 3-way crossover study that included 23 healthy male volunteers who had fasted, had ingested 240 mL of skim milk, or had consumed a standard high-fat breakfast. The subjects' mean age and weight were 26.5 years and 73.2 kg, respectively; 17 were white, 5 Hispanic, and 1 black. Neither skim milk nor the high-fat breakfast had a statistically significant effect on sparfloxacin absorption, as reflected in the maximum plasma concentration (Cmax) and area under the plasma concentration-time curve (AUC). Ninety percent confidence limits for logarithmically transformed AUC from time zero to infinity and Cmax were within the 80% to 125% range, demonstrating that the rate and extent of sparfloxacin absorption with skim milk or a high-fat breakfast were not different from those under fasted conditions. As indicated by an increase in the time to Cmax from 3.6 to 5.4 hours, the high-fat breakfast slightly delayed the onset of sparfloxacin absorption. Skim milk and the high-fat breakfast did not significantly affect the elimination kinetics of sparfloxacin. Sparfloxacin was well tolerated in all 3 treatment groups. Despite the apparent delay in the onset of absorption, the bioavailability of sparfloxacin in the healthy male subjects in this study population was not affected by concomitant administration with skim milk or a high-fat meal. Accordingly, the results suggest that sparfloxacin can be administered without regard to the ingestion of milk or meals.

The new fluoroquinolones: A critical review

OBJECTIVE

This paper reviews the literature available on the new fluoroquinolones - clinafloxacin, gatifloxacin, grepafloxacin, levofloxacin, moxifloxacin, sparfloxacin and trovafloxacin - to compare these agents with each other and contrast them with ciprofloxacin, an older fluoroquinolone.

DATA SELECTION

Published papers used were obtained by searching MEDLINE for articles published between 1994 and 1998, inclusive. References of published papers were also obtained and reviewed. Abstracts from scientific proceedings were reviewed.

DATA EXTRACTION

Due to the limited data available on several of the agents, criteria for study inclusion in the in vitro, pharmacokinetics and in vivo sections were not restrictive.

DATA SYNTHESIS

The new fluoroquinolones offer excellent Gram-negative bacillary activity and improved Gram-positive activity (eg, against Streptococcus pneumoniae and Staphylococcus aureus) over ciprofloxacin. Clinafloxacin, gatifloxacin, moxifloxacin, sparfloxacin and trovafloxacin display improved activity against anaerobes (eg, Bacteriodes fragilis). All of the new fluoroquinolones have a longer serum half-life than ciprofloxacin (allowing for once daily dosing), and several are eliminated predominantly by nonrenal means. No clinical trials are available comparing the new fluoroquinolones with each other. Clinical trials comparing the new fluoroquinolones with standard therapy have demonstrated good efficacy in a variety of infections. Their adverse effect profile is similar to that of ciprofloxacin. Clinafloxacin and sparfloxacin cause a high incidence of phototoxicity (1.5% to 14% and 2% to 11.7%, respectively), grepafloxacin causes a high incidence of taste perversion (9% to 17%) and trovafloxacin causes a high incidence of dizziness (11%). They all interact with metal ion-containing drugs (eg, antacids), and clinafloxacin and grepafloxacin interact with theophylline. The new fluoroquinolones are expensive; however, their use may result in savings in situations where, because of their potent and broad spectrum of activity, they can be used orally in place of intravenous antibiotics.

CONCLUSIONS

The new fluoroquinolones offer advantages over ciprofloxacin in terms of improved in vitro activity and pharmacokinetics. Whether these advantages translate into improved clinical outcomes is presently unknown. The new fluoroquinolones have the potential to emerge as important therapeutic agents in the treatment of respiratory tract and genitourinary tract infections.

Trovafloxacin: a new fluoroquinolone

OBJECTIVE

To review the pharmacology, antimicrobial activity, pharmacokinetics, clinical efficacy, and safety of trovafloxacin.

DATA SOURCES

A MEDLINE search (January 1966-April 1998) was conducted for relevant literature using the terms CP-99,219, CP-116,519, trovafloxacin, and alatrofloxacin. Abstracts published by the American Society of Microbiology during 1995-1997 meetings were also reviewed.

STUDY SELECTION AND DATA EXTRACTION

All in vitro, animal, and human studies were reviewed for the antimicrobial activity, pharmacokinetics, efficacy, and safety of trovafloxacin.

DATA SYNTHESIS

Trovafloxacin is a new fluoroquinolone with enhanced activity against gram-positive and anaerobic microorganisms. The oral bioavailability under fasting conditions is approximately 88%. The elimination half-life of trovafloxacin is approximately 10 hours. Less than 10% of trovafloxacin is eliminated unchanged in the urine. Trovafloxacin is effective in the treatment of community-acquired pneumonia and nosocomial pneumonia with cure rates of > 90% and 77%, respectively. Trovafloxacin is comparable with ceftriaxone in the treatment of meningococcal meningitis in children; each produces a cure rate of approximately 90%. In treatment of uncomplicated urinary tract infection, both ciprofloxacin and trovafloxacin achieve an eradication rate of > or = 93%. Trovafloxacin is similar to ofloxacin in the treatment of urogenital Chlamydia trachomatis and acute exacerbations of chronic bronchitis, with clinical success in 97% of patients with each drug. The common adverse effects of trovafloxacin include dizziness, headache, and gastrointestinal intolerance.

CONCLUSIONS

The advantages of once-daily dosing and enhanced activity of trovafloxacin against gram-positive and anaerobic organisms may expand its use over available fluoroquinolones. Further studies are needed to define its role in the treatment of various infectious diseases.

Trovafloxacin: an overview

Trovafloxacin, a new synthetic naphthyridine fluoroquinolone antibiotic, is a broad-spectrum agent available orally and intravenously. It was recently approved by the Food and Drug Administration for the treatment of selected pulmonary, surgical, intraabdominal, gynecologic, pelvic, skin, and urinary tract infections. Its spectrum of activity includes aerobic gram-positive and gram-negative organisms as well as anaerobic pathogens. It is rapidly absorbed after oral administration, achieves good tissue and cerebrospinal fluid penetration, and has a half-life that allows once-daily dosing. It is hepatically metabolized, and dosage adjustments are necessary for patients with severe hepatic dysfunction but not for those with mild or moderate dysfunction or renal dysfunction. The drug has a favorable safety profile, and a high tendency for transient first-dose dizziness and/or lightheadedness in young women. Similar to other quinolones, trovafloxacin should not be taken with antacids that contain aluminum or magnesium, sucralfate, or ferrous sulfate. Trovafloxacin may prove beneficial as it allows for oral or intravenous monotherapy against indicated infections that normally require multidrug, broad-spectrum antibiotic coverage.

In vitro activity of trovafloxacin against ciprofloxacin-susceptible and -resistant clinical bacterial isolates and assessment of the trovafloxacin disk test

A total of 4241 consecutive clinical bacterial isolates from 10 North American medical centers were tested for susceptibility to trovafloxacin. Trovafloxacin was significantly more active than ciprofloxacin against Gram-positive bacteria, Acinetobacter spp., and Stenotrophomonas maltophilia, and resistance to trovafloxacin occurred in these groups only among isolates with high-level resistance (MIC > or = 16 micrograms/mL) to ciprofloxacin. With other species, the two drugs had comparable activity. Concerns about staphylococci and Pseudomonas aeruginosa with trovafloxacin MICs of 2.0 micrograms/mL (the upper end of the susceptible category) are discussed. Results of trovafloxacin disk diffusion test on more than 3200 nonfastidious isolates supported the FDA-approved zone size interpretive criteria when the MIC breakpoint of < or = 2.0 micrograms/mL is used to define the trovafloxacin-susceptible category.

Expanded activity and utility of the new fluoroquinolones: a review

In general, the fluoroquinolones developed over the past few years have greater potency, a broader spectrum of antimicrobial activity, greater in vitro efficacy against resistant organisms, and a better safety profile than other antimicrobial agents, including the older quinolones. The present review focuses on 4 new quinolones that are commercially available (levofloxacin, trovafloxacin, grepafloxacin, and sparfloxacin) and 3 that are currently undergoing clinical trials (gatifloxacin, moxifloxacin, and clinafloxacin). Examination of the minimum inhibitory concentrations of these drugs against gram-positive, gram-negative, anaerobic, and atypical organisms demonstrates their increased potency in vitro. The available clinical evidence, although sparse, suggests the potential enhanced efficacy of these drugs in the treatment of various community-acquired and nosocomial infections (eg, respiratory, urinary tract, and skin infections and sexually transmitted diseases). Compared with ciprofloxacin, their pharmacokinetic profiles demonstrate equivalent or greater bioavailability, higher plasma concentrations, and increased tissue penetration, as reflected in greater volume of distribution. Adverse events seen with most quinolones are mild. Serious adverse effects that may occur are phototoxicity (particularly with sparfloxacin) and prolongation of the QTc interval (seen with sparfloxacin and grepafloxacin). Drug interactions are possible between multivalent cation-containing compounds and all quinolones and between theophylline and both ciprofloxacin and grepafloxacin. Drugs that prolong the QTc interval should not be coadministered with sparfloxacin and grepafloxacin. Step-down therapy, a therapeutic and cost-saving advantage possible with gatifloxacin, levofloxacin, and moxifloxacin, allows the switching of patients from intravenous to oral therapy without having to change the dosage regimen or class of antibiotics. In addition to shortening the hospital stay and reducing the risk of venous complications, step-down therapy has been shown to cut hospital drug costs by 40% and hospitalization costs by 20%.

Safety and tolerability of intravenous-to-oral treatment and single-dose intravenous or oral prophylaxis with trovafloxacin

BACKGROUND

The new fourth-generation fluoroquinolone, trovafloxacin, is active in vitro against gram-positive and gram-negative organisms, atypical pathogens, and anaerobes, and has pharmacokinetics permitting once-daily intravenous or oral dosing. Safety/tolerability data from phase II/III clinical trials of sequential intravenous alatrofloxacin to oral trovafloxacin and single-dose intravenous or oral prophylaxis are summarized.

METHODS

All trials were double-blind, randomized, and multicenter. In multidose trials with alatrofloxacin, 1,257 patients requiring initial intravenous therapy received once-daily alatrofloxacin (trovafloxacin prodrug, 200 or 300 mg/day) followed by oral 200 mg/day trovafloxacin. An additional 444 patients received a single alatrofloxacin or trovafloxacin dose prophylactically for surgical procedures.

RESULTS

Therapy with alatrofloxacin was well tolerated. The most common treatment-related adverse events in studies of intravenous alatrofloxacin followed by oral trovafloxacin were nausea, headache, insertion site reaction, and dizziness. In single-dose intravenous or oral prophylaxis studies, insertion-site reaction, pruritus, and insertion-site pain were the most common treatment-related adverse events. No serious quinolone toxicity or drug interactions were reported. The incidence of serious treatment-related adverse events was < 1% in both the alatrofloxacin and comparator groups. In comparative trials, mortality due to all causes after trovafloxacin was similar to that after comparative agents; there was no mortality related to trovafloxacin administration.

CONCLUSION

In this large patient sample, intravenous alatrofloxacin followed by oral trovafloxacin was safe and well tolerated. Serious adverse events, such as phototoxicity, cardiovascular toxicity, and hemolytic anemia associated with older fluoroquinolones, were not noted with trovafloxacin. No interactions of trovafloxacin with other drugs were reported. The safety and tolerability of trovafloxacin, along with in vitro activity against key pathogens and pharmacokinetics permitting once-daily administration, support its oral and intravenous use in patients with obstetric, gynecologic, and intra-abdominal infections as well as for prophylaxis of surgical infection.

Overview of quinolones in the treatment and prevention of surgical infection

Postoperative infection remains a complication of surgical procedures, resulting in increased morbidity, mortality, and cost. The frequent polymicrobial etiology and emerging patterns of resistance continue to compromise cure rates. Although quinolones have many attractive properties for the surgical setting, combination therapy is routinely indicated for appropriate coverage. Advanced-generation quinolones, such as trovafloxacin, offer an increased antimicrobial spectrum, including activity against important surgical pathogens, and longer elimination half-lives. These newer agents may be used intravenously or orally as once-daily single-agent therapy for surgical prophylaxis, and in place of combination therapy for complex intra-abdominal and pelvic infections.

The bioavailability of nasogastric versus tablet-form oral trovafloxacin in healthy subjects

BACKGROUND

Patients in the hospital, as well as those in home care settings, often require nutritional supplementation with enteral feeding solutions. In addition, patients with serious infections who are clinically unstable often cannot maintain adequate intake by mouth and may require an alternative to oral antibiotic administration. However, delivery of crushed oral formulations of drugs via nasogastric tubes is often carried out without adequate bioavailability data, and this method of administration may not always be equivalent to oral drug delivery.

METHODS

In an open-label, randomized, four-period, four-treatment, cross-over study, 24 healthy volunteers were given one dose of each of the following treatments, with a 7-day wash-out between dosing periods: Treatment A: two 100-mg trovafloxacin tablets given orally with 240 mL water; Treatment B: two crushed 100-mg trovafloxacin tablets suspended in water and administered through a nasogastric tube into the stomach; Treatment C: two crushed 100-mg trovafloxacin tablets suspended in water and administered through a nasogastric tube into the duodenum; or Treatment D: two crushed 100-mg trovafloxacin tablets suspended in water and given through a nasogastric tube into the stomach concomitantly with an enteral feeding solution (240 mL full-strength Osmolite).

RESULTS

Pharmacokinetic analyses showed that the bioavailability of trovafloxacin after administration of crushed tablets into the stomach with or without concomitant enteral feeding was not significantly different from that of the orally administered whole tablets: the 90% confidence limits of the area under the concentration-time curve (AUC(0-infinity)) for Treatment B versus Treatment A (91.3%, 109.5%) and Treatment D versus Treatment A (91.6%, 109.9%) were well within the bioequivalence criteria of 80% to 125%. Results of analysis of variance (ANOVA) indicated no significant sequence, period, or treatment-by-period interaction effects. Administration of trovafloxacin into the duodenum (Treatment C) resulted in reduced systemic exposure to trovafloxacin, with a 31% decrease in AUC(0-infinity) and a 30% decrease in peak serum concentration (Cmax) compared to oral administration. Time to peak serum concentration (Tmax) was 1.7 hours after oral administration of trovafloxacin and 1.1 hours after administration directly into the stomach or duodenum through a nasogastric tube in the absence of concomitant enteral feeding. All four treatments were well tolerated; no participant discontinued the study due to adverse events and no serious adverse events were reported.

CONCLUSIONS

These results showed that administration of crushed trovafloxacin tablets through a nasogastric tube into the stomach, with or without concomitant enteral feeding, achieves absorption and tolerability comparable to those of orally administered trovafloxacin tablets.

Penetration of trovafloxacin into gynecologic tissues

BACKGROUND

This randomized open-label study assessed the penetration into gynecologic tissues of trovafloxacin, a new broad-spectrum, fourth-generation fluoroquinolone with in vitro activity against anaerobes, gram-positive, gram-negative, and atypical pathogens.

METHODS

Women undergoing hysterectomy or hysterectomy and adnexectomy received 200 mg trovafloxacin orally before surgery as a single dose or as multiple doses. Samples of genital tract tissue and serum were obtained simultaneously during surgery.

RESULTS

In the single-dose group, trovafloxacin concentrations in genital tract tissues were measurable for up to 30 hours. Tissue concentrations of trovafloxacin after multiple doses were comparable to those after single doses. Mean tissue: serum concentration ratios after a single dose were greatest in the ovary (1.6 microg/g) and comparable in uterus, myometrium, cervix, and fallopian tubes (0.5 to 0.7 microg/g). Adverse events after a single dose were minor.

CONCLUSIONS

A daily dose of 200 mg trovafloxacin produces gynecologic tissue concentrations that persist for up to 30 hours at levels necessary to prevent or treat pelvic infections. This dosing regimen is well tolerated.

The pharmacokinetic effects of coadministration of morphine and trovafloxacin in healthy subjects

BACKGROUND

Morphine and antibiotics are frequently coadministered in the surgical setting. These agents may interact, reducing the efficacy of the antibiotic or increasing the toxicity of morphine. It is therefore important to determine whether antibiotics that might be used for surgical prophylaxis have the potential to change the pharmacokinetics of morphine. It is equally important to learn whether morphine affects the plasma levels of antibiotics and thus may potentially influence their efficacy or tolerability.

METHODS

This open, randomized, placebo-controlled, three-treatment, three-period cross-over study enrolled 19 healthy volunteers. Oral trovafloxacin (200 mg), a novel fluoroquinolone antibiotic, and intravenous morphine (0.15 mg/kg) were coadministered, and the effects on the pharmacokinetics of each drug and on changes in the pharmacologic action of morphine, estimated from its effects on respiratory rate and level of sedation, were examined.

RESULTS

When trovafloxacin was coadministered with morphine, the half-life of trovafloxacin was unchanged; however, the ratio of the area under the serum concentration versus time curve (AUC(0-infinity)) estimates for trovafloxacin/morphine versus trovafloxacin/placebo was 63.8% (95% confidence interval [CI], 40.7% to 100.3%), indicating a 36% reduction in the bioavailability of trovafloxacin. The ratio of the mean maximum serum concentration (Cmax) estimates of trovafloxacin for the two treatments was 53.8% (95% CI: 36.1% to 80.1%), indicating a 46% reduction in Cmax. The time to Cmax was delayed by 4 hours. With trovafloxacin coadministration, there were no statistically significant changes in either the mean relative bioavailability of morphine or that of its metabolite, 6beta-glucuronide-morphine. Coadministration of trovafloxacin did not exacerbate the reduction in respiratory rate or increase the number of side effects associated with morphine administration.

CONCLUSIONS

Coadministration of trovafloxacin and morphine reduces the bioavailability and maximum serum concentrations of trovafloxacin. However, elimination of oral trovafloxacin is not impaired, suggesting that the efficacy of trovafloxacin could be maintained in many patients who receive concomitant morphine. Morphine plasma levels and pharmacologic effects are not significantly altered by coadministration of trovafloxacin. Despite their similar metabolic pathways, the trovafloxacin/morphine combination neither exacerbates the respiratory depressant effects of morphine nor increases the frequency of side effects when compared with placebo/morphine treatment. These results suggest that the efficacy of trovafloxacin may be maintained when coadministered with morphine. Concurrent administration of trovafloxacin and morphine is unlikely to alter the pharmacologic effects of morphine.

Oral trovafloxacin compared with intravenous cefoxitin in the prevention of bacterial infection after elective vaginal or abdominal hysterectomy for nonmalignant disease. Trovafloxacin Surgical Group

BACKGROUND

Trovafloxacin is a new fourth-generation fluoroquinolone whose pharmacokinetics and in vitro activity suggest that it is well suited for antibiotic prophylaxis in elective hysterectomy.

METHODS

In a randomized, double-blind, multicenter study, parallel groups of women 18 years of age or older received either 200 mg trovafloxacin by mouth and intravenous (i.v.) placebo or 2 g cefoxitin by i.v. infusion and placebo by mouth before elective vaginal or abdominal hysterectomy for nonmalignant disease.

RESULTS

In the 103 and 97 patients in the trovafloxacin and cefoxitin groups, respectively, who were evaluable for efficacy, the prophylactic success rates at hospital discharge (96% in both groups) and 30 +/- 6 days after hysterectomy (88% and 91% in the trovafloxacin and cefoxitin groups, respectively) were statistically equivalent. Both antibiotics were well tolerated.

CONCLUSION

A single oral 200 mg dose of trovafloxacin is as effective and safe as a standard cefoxitin parenteral regimen in the prevention of primary bacterial infection after elective vaginal or abdominal hysterectomy for nonmalignant disease.

Comparative antimicrobial activity of trovafloxacin tested against 3049 Streptococcus pneumoniae isolates from the 1997-1998 respiratory infection season

Trovafloxacin is a new fluorinated naphthyridone having expanded activity against Gram-positive and anaerobic pathogens compared with ciprofloxacin or levofloxacin or ofloxacin. A multicenter in vitro trial (201 sites) was initiated in late 1997 to study the comparative activity of trovafloxacin against Streptococcus pneumoniae strains during the recently completed respiratory disease season. Each laboratory was asked to test 20 to 30 recent isolates (3049 strains) by the Etest (AB BIODISK, Solna, Sweden) method with observed phenotypes with elevated trovafloxacin results (MIC, > 1 microgram/mL) confirmed by the monitor laboratory (University of Iowa College of Medicine). Approximately one-third (34.0%) of isolates were penicillin nonsusceptible (12.8% high-level resistance at > or = 2 micrograms/mL). Also 20.4% and 4.5% of strains were resistant to macrolides (erythromycin) and ceftriaxone, respectively. The macrolide resistance rate was lowered to 16.8% when the adverse effect of CO2 incubation was considered. Only 0.3% of S. pneumoniae were vancomycin-nonsusceptible using the current National Committee for Clinical Laboratory Standards breakpoint (< or = 1 microgram/mL) with nearly all results were at 1.5 micrograms/mL. Trovafloxacin (MIC50 and MIC90, 0.094 and 0.19 microgram/mL, respectively) was eight fold more potent than levofloxacin (MIC90, 0.75 and 1.5 micrograms/mL), and fewer strains (0.10%) were discovered with high-level resistance (MIC, > or = 8 micrograms/mL). The four resistant isolates from different states had alterations in both par C and gyr A. Trovafloxacin had the best potency observed against contemporary pneumococcal isolates, and has a spectrum (> 99.8% susceptible) for an orally administered agent that was comparable to the tested parenteral glycopeptide, vancomycin (> 99.7%). Blood and spinal-fluid culture isolates were generally more susceptible to penicillin (74.4 to 75.6%), other beta-lactams, and erythromycin (84.4%); throat and sputum isolates were significantly more resistant (p < 0.01). Increases in resistance among S. pneumoniae strains to beta-lactams and erythromycin were documented in all geographic regions monitored, other resistances also continue to evolve, and high-level fluoroquinolone resistance remains very rare.

Trovafloxacin

Trovafloxacin is a fluoroquinolone antibacterial agent with a broad spectrum of activity. Trovafloxacin has similar or 2-fold lower activity than ciprofloxacin against Enterobacteriaceae and Pseudomonas aeruginosa. Against Haemophilus influenzae and Moraxella catarrhalis, trovafloxacin has similar activity to ciprofloxacin. Other susceptible Gram-negative pathogens include Neisseria gonorrhoeae, Chlamydia trachomatis and mycoplasmas. The drug is active against Gram-positive bacteria and consistently displayed greater activity (2- to 8-fold) than ciprofloxacin against all staphylococci and streptococci tested; activity included methicillin-resistant staphylococci and penicillin-resistant Streptococcus pneumoniae. Trovafloxacin has some activity against vancomycin-resistant enterococci. Anaerobes such as Bacteroides and Clostridium spp. are also susceptible to trovafloxacin. Preliminary clinical data suggest that trovafloxacin is effective in the treatment of patients with upper and lower respiratory tract and uncomplicated urinary tract infections and infections caused by C. trachomatis or N. gonorrhoeae. The most frequently noted adverse event with trovafloxacin is dizziness which is reported in 11% of patients versus 3% of those receiving comparator agents. Other commonly reported events (> 1% of patients) are nausea, headache, vomiting, vaginitis and diarrhoea.