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Prueksaritanont T, Hochman JH, Meng Y, Pudvah NT, Barrish A, Ma B, Yamazaki M, Fernandez-Metzler C, Lin JH. Renal elimination of a novel and potent αvβ3integrin antagonist in animals. Xenobiotica 2008; 34:1059-74. [PMID: 15801548 DOI: 10.1080/00498250400015277] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Compound A (3-{2-oxo-3-[3-(5,6,7,8-tetrahydro-[1,8]napthyridin-2-yl)propyl]-imidazolidin-1-yl}-3(S)-(6-methoxy-pyridin-3-yl)propionic acid), a hydrophilic zwitter-ion, is a potent and selective alphavbeta3 integrin antagonist currently under clinical development for the treatment of osteoporosis. The mechanism of renal excretion of compound A was investigated using a combination of in vivo and in vitro approaches. In rats, renal excretion of compound A involved tubular secretion; ratios between renal clearance, corrected for unbound fraction in plasma (CLr,u) and glomerular filtration rate (GFR) were greater than unity (2-5). The tubular secretion of compound A was saturable at high plasma levels (> 26 microM), and was inhibited significantly, although modestly (about twofold) by relatively high plasma concentrations of the organic anion PAH (160 microM) and the cation cimetidine (about 400 microM), but not by the P-gp inhibitor quinidine (about 50 microM). However, compound A (about 100 microM) had a minimal effect on CLr/GFRs for cimetidine and PAH. In rhesus monkeys, renal elimination of compound A also involved tubular secretion, with a CLr,u/GFR ratio of about 30. The renal secretion of compound A was not affected by either cimetidine (about 120 microM) or PAH (about 80 microM). Similarly, compound A (about 40 microM) had a minimal effect on the renal tubular secretion of both cimetidine and PAH. At the doses studied, neither rat nor monkey plasma protein binding of compound A, cimetidine or PAH was affected in the presence of each other. In vitro transport studies showed that compound A was not a substrate for P-gp in the Caco-2, human MDR1 and mouse mdr1a transfected LLC-PK1 cell lines. In an uptake study using rOAT1 and rOAT3 transfected HEK cell lines, compound A was shown to be a substrate for rat OAT3 (Km= 15 microM), but not rat OAT1. The results suggest that the tubular secretion of compound A is not mediated by P-gp, but rather is mediated, at least in part, via the organic anion transporter OAT3, the renal transporter shown to be capable of transporting both the organic anion PAH and the organic cation cimetidine. Although there is a possibility for pharmacokinetic interactions between compound A and substrates or inhibitors of OAT3, at the renal excretion level, the magnitude of interaction would likely be modest in humans at clinically relevant doses.
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Mills DA, Fekrazad HM, Verschraegen CF. SNS-595, a naphthyridine cell cycle inhibitor and stimulator of apoptosis for the treatment of cancers. CURRENT OPINION IN INVESTIGATIONAL DRUGS (LONDON, ENGLAND : 2000) 2008; 9:647-657. [PMID: 18516764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Sunesis Pharmaceuticals Inc, under license from Dainippon Sumitomo Pharma Co Ltd, is developing SNS-595, a naphthyridine cell cycle inhibitor and apoptosis stimulator, for the potential treatment of a variety of solid and hematological malignancies. Phase I clinical trials had been completed in several solid tumor types and phase II clinical trials had been completed in patients with small-cell lung cancer and NSCLC. A phase II clinical trial in patients with platinum-resistant ovarian cancer and phase I/II and phase II clinical trials in patients with acute leukemias were ongoing at the time of publication.
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Egbertson MS, Moritz HM, Melamed JY, Han W, Perlow DS, Kuo MS, Embrey M, Vacca JP, Zrada MM, Cortes AR, Wallace A, Leonard Y, Hazuda DJ, Miller MD, Felock PJ, Stillmock KA, Witmer MV, Schleif W, Gabryelski LJ, Moyer G, Ellis JD, Jin L, Xu W, Braun MP, Kassahun K, Tsou NN, Young SD. A potent and orally active HIV-1 integrase inhibitor. Bioorg Med Chem Lett 2006; 17:1392-8. [PMID: 17194584 DOI: 10.1016/j.bmcl.2006.11.080] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2006] [Revised: 11/20/2006] [Accepted: 11/30/2006] [Indexed: 12/01/2022]
Abstract
A 1,6-naphthyridine inhibitor of HIV-1 integrase has been discovered with excellent inhibitory activity in cells, good pharmacokinetics, and an excellent ability to inhibit virus with mutant enzyme.
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Mikamo H, Tanaka K, Watanabe K. [Evaluation of efficacy of oral quinolone against Streptococcus pneumoniae AND Haemophilus influenzae with the use of Monte Carlo simulation]. THE JAPANESE JOURNAL OF ANTIBIOTICS 2006; 59:468-73. [PMID: 17334064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We investigated the efficacies of various administration methods for levofloxacin (LVFX) and tosufloxacin (TFLX) against 161 isolates of Streptococcus pneumoniae and 309 isolates of Haemophilus influenzae isolated in Gifu prefecture, using Monte Carlo simulation. The pharmacokinetic parameters of the fluoroquinolones were calculated from changes in blood concentration in healthy adults. Monte Carlo simulation was performed for 1,000 times to determine the AUC/MIC target attainment rates for various administration methods for fluoroquinolones (LVFX: 100 mgx3, 200 mgx2, 500 mgx 1, TFLX: 150 mgx3, 300 mgx2) with Crystal Ball 7. For S. pneumoniae, target attainment rates ofAUC/MIC; 30 were 47.18%, 75.54%, 89.16%, 93.63% and 98.63% for LVFX 100mgx3, LVFX 200mgx2, LVFX 500mgxl, TFLX 150mgx3 and TFLX 300mgx2, respectively. For H. influenzae, target attainment rates of AUC/MIC; 125 were 99.20%, 99.05%, 99.54%, 99.66% and 100% for LVFX 100mgx3, LVFX 200mgx2, LVFX 500mgxl, TFLX 150mgx3 and TFLX 300mgx2, respectively. These results suggest that administration methods might have a large impact on the efficacy of treatment with oral fluoroquinolones, and to determine administration method based on PK/PD would be important in clinical practices.
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Natarajan SR, Liu L, Levorse M, Thompson JE, O'Neill EA, O'Keefe SJ, Vora KA, Cvetovich R, Chung JY, Carballo-Jane E, Visco DM. p38 MAP kinase inhibitors. Part 5: Discovery of an orally bio-available and highly efficacious compound based on the 7-amino-naphthyridone scaffold. Bioorg Med Chem Lett 2006; 16:5468-71. [PMID: 16945534 DOI: 10.1016/j.bmcl.2006.06.084] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2006] [Revised: 06/07/2006] [Accepted: 06/08/2006] [Indexed: 11/22/2022]
Abstract
A new sub-class of p38 inhibitors represented by 7-amino-naphthyridone have been discovered. Benchmark compound 16 potently inhibited p38 in vitro, was functionally active, and displayed excellent pharmacokinetic profiles in two animal species. Compound 16 reduced inflammation in animal disease models at EC(50) doses as low as 0.2mpk.
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Atack JR, Pike A, Marshall G, Stanley J, Lincoln R, Cook SM, Lewis RT, Blackaby WP, Goodacre SC, McKernan RM, Dawson GR, Wafford KA, Reynolds DS. The in vivo properties of pagoclone in rat are most likely mediated by 5′-hydroxy pagoclone. Neuropharmacology 2006; 50:677-89. [PMID: 16430927 DOI: 10.1016/j.neuropharm.2005.11.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2005] [Revised: 11/25/2005] [Accepted: 11/25/2005] [Indexed: 11/30/2022]
Abstract
The cyclopyrrolone pagoclone binds with roughly equivalent high affinity (0.7-9.1nM) to the benzodiazepine binding site of human recombinant GABA(A) receptors containing either an alpha1, alpha2, alpha3 or alpha5 subunit. However, whereas it was a partial agonist at alpha1-, alpha2- and alpha5-containing GABA(A) receptors, pagoclone was a full agonist at receptors containing an alpha3 subunit. In the rat elevated plus maze assay pagoclone (3mg/kg) had significant anxiolytic-like activity but at all three doses tested (0.3, 1 and 3mg/kg p.o.) it produced a significant reduction in the total distance travelled. This sedative-like effect was confirmed in rat chain-pulling and spontaneous locomotor assays. Surprisingly, in the plasma and brain samples derived from the elevated plus maze assay, the major metabolite of pagoclone, 5'-hydroxy pagoclone, was present at 10-20-fold higher concentrations relative to the parent compound. In order to establish whether this metabolite might have pharmacological activity, we measured its affinity and efficacy profile and found that both were comparable to those of pagoclone with the exception that efficacy at the alpha1 subtype was considerably greater for 5'-hydroxy pagoclone compared with the parent. This metabolite had significant anxiolytic-like activity in the elevated plus maze but at these same doses (0.3-3mg/kg p.o.) also produced sedation. It is therefore likely that in rats 5'-hydroxy pagoclone mediates the majority of the pharmacological actions following pagoclone administration.
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Buurman ET, Johnson KD, Kelly RK, MacCormack K. Different modes of action of naphthyridones in gram-positive and gram-negative bacteria. Antimicrob Agents Chemother 2006; 50:385-7. [PMID: 16377719 PMCID: PMC1346805 DOI: 10.1128/aac.50.1.385-387.2006] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Naphthyridones that were recently described as a class of translation inhibitors in gram-positive bacteria mediate their mode of action via GyrA in Haemophilus influenzae and Escherichia coli. These are the first examples of compounds in which modes of action in different bacterial pathogens are mediated through widely different targets.
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Padeĭskaia EN. [Fluoroquinolones and therapy of bacterial meningitis]. ANTIBIOTIKI I KHIMIOTERAPIIA = ANTIBIOTICS AND CHEMOTERAPY [SIC] 2006; 51:53-64. [PMID: 17165260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
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Fukuda Y, Takahata M, Mitsuyama J. Pharmacodynamic evaluation of tosufloxacin against Streptococcus pneumoniae in an in vitro model simulating serum concentration. J Infect Chemother 2006; 12:1-8. [PMID: 16506083 DOI: 10.1007/s10156-005-0420-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2005] [Accepted: 11/24/2005] [Indexed: 11/27/2022]
Abstract
We compared the antibacterial effects and the emergence of resistance to tosufloxacin or levofloxacin for Streptococcus pneumoniae by simulating the serum concentration according to the Japanese clinical regimens using an in vitro pharmacokinetic-pharmacodynamic model. For quinolone-susceptible strain ATCC49619, tosufloxacin showed bactericidal activity, given that both the AUC(0-24h)/MIC ratios at the dosage of 150 mg t.i.d. and 300 mg b.i.d. of tosufloxacin tosilate were 138 and 193, and the C(max)/MIC ranges were 7.93-10.2 and 15.9-17.6, respectively, which were greater than those of levofloxacin (100 mg t.i.d. and 200 mg b.i.d.). The greater area above the killing curves (AAKCs) or shorter time to achieve 99.9% killing (99.9% KT) in both models of tosufloxacin than those of levofloxacin was related to their larger AUC(0-24h)/MIC and C(max)/MIC. Exposure of only 100 mg t.i.d. of levofloxacin led to outgrowth of the parC mutants, which were twofold less susceptible to levofloxacin than the parent strain. Neither of the tosufloxacin tosilate regimens resulted in isolation of resistant mutants of this strain. For the parC mutant strain D-3197, both the AUC(0-24h)/MIC and C(max)/MIC ratios of tosufloxacin were greater than those of levofloxacin, which resulted in comparable or better bactericidal activity as compared to those of levofloxacin. However, both fluoroquinolones and both regimens led to outgrowth of resistant mutants, which possessed a mutation in gyrA in addition to parC. In conclusion, tosufloxacin is superior to levofloxacin in bactericidal activity against S. pneumoniae in the Japanese clinical regimens, especially in the quinolone-susceptible strain, without emergence of resistant subpopulations.
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Ramanathan S, Karupiah S, Nair NK, Olliaro PL, Navaratnam V, Wernsdorfer WH, Mansor SM. A new and simple solid-phase extraction method for LC determination of pyronaridine in human plasma. J Chromatogr B Analyt Technol Biomed Life Sci 2005; 824:45-50. [PMID: 16046285 DOI: 10.1016/j.jchromb.2005.06.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2004] [Revised: 06/14/2005] [Accepted: 06/24/2005] [Indexed: 11/19/2022]
Abstract
A new approach using a simple solid-phase extraction technique has been developed for the determination of pyronaridine (PND), an antimalarial drug, in human plasma. After extraction with C18 solid-phase sorbent, PND was analyzed using a reverse phase chromatographic method with fluorescence detection (at lambda(ex)=267 nm and lambda(em)=443 nm). The mean extraction recovery for PND was 95.2%. The coefficient of variation for intra-assay precision, inter-assay precision and accuracy was less than 10%. The quantification limit with fluorescence detection was 0.010 microg/mL plasma. The method described herein has several advantages over other published methods since it is easy to perform and rapid. It also permits reducing both, solvent use and sample preparation time. The method has been used successfully to assay plasma samples from clinical pharmacokinetic studies.
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Embrey MW, Wai JS, Funk TW, Homnick CF, Perlow DS, Young SD, Vacca JP, Hazuda DJ, Felock PJ, Stillmock KA, Witmer MV, Moyer G, Schleif WA, Gabryelski LJ, Jin L, Chen IW, Ellis JD, Wong BK, Lin JH, Leonard YM, Tsou NN, Zhuang L. A series of 5-(5,6)-dihydrouracil substituted 8-hydroxy-[1,6]naphthyridine-7-carboxylic acid 4-fluorobenzylamide inhibitors of HIV-1 integrase and viral replication in cells. Bioorg Med Chem Lett 2005; 15:4550-4. [PMID: 16102965 DOI: 10.1016/j.bmcl.2005.06.105] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2005] [Revised: 06/30/2005] [Accepted: 06/30/2005] [Indexed: 10/25/2022]
Abstract
Introduction of a 5,6-dihydrouracil functionality in the 5-position of N-(4-fluorobenzyl)-8-hydroxy-[1,6]naphthyridine-7-carboxamide 1 led to a series of highly active HIV-1 integrase inhibitors. These compounds displayed low nanomolar activity in inhibiting both the strand transfer process of HIV-1 integrase and viral replication in cells. Compound 11 is a 150-fold more potent antiviral agent than 1, with a CIC(95) of 40 nM in the presence of human serum. It displays good pharmacokinetics when dosed in rats and dogs.
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Saravolatz L, Manzor O, Pawlak J, Belian B. Antimicrobial activity and a comparison of published pharmacodynamics of gemifloxacin and eight fluoroquinolones against Streptococcus pneumoniae. Int J Antimicrob Agents 2005; 26:81-4. [PMID: 15951159 DOI: 10.1016/j.ijantimicag.2005.03.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2004] [Accepted: 03/10/2005] [Indexed: 11/18/2022]
Abstract
Gemifloxacin was evaluated for its in vitro activity and was compared with eight fluoroquinolones. Pharmacodynamic comparisons were made based on published pharmacokinetic information. Gemifloxacin demonstrated excellent in vitro activity (minimum inhibitory concentration necessary to inhibit 90% of the strains tested, MIC90 = 0.03 mg/L (range 0.0019-0.03 mg/L)) against 199 strains of Streptococcus pneumoniae. Its activity was not influenced by penicillin or ciprofloxacin non-susceptibility. Gemifloxacin demonstrated excellent pharmacodynamic parameters, with a Cmax/MIC90 of 67 (where Cmax is the peak serum level) and an AUC/MIC90 of 297 (where AUC is the area under the curve). Compared with the other eight fluoroquinolones tested, gemifloxacin demonstrated the best in vitro activity and Cmax/MIC90.
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Bhavnani SM, Andes DR. Gemifloxacin for the treatment of respiratory tract infections: in vitro susceptibility, pharmacokinetics and pharmacodynamics, clinical efficacy, and safety. Pharmacotherapy 2005; 25:717-40. [PMID: 15899734 DOI: 10.1592/phco.25.5.717.63583] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Gemifloxacin is a synthetic fluoroquinolone antimicrobial agent exhibiting potent activity against most gram-negative and gram-positive organisms, such as the important community-acquired respiratory pathogens Streptococcus pneumoniae (including multidrug-resistant S. pneumoniae), Haemophilus influenzae , and Moraxella catarrhalis . The agent's mechanism of action involves dual targeting of two essential bacterial enzymes: DNA gyrase and topoisomerase IV. Gemifloxacin was approved by the Food and Drug Administration in April 2003 for treatment of community-acquired pneumonia and acute bacterial exacerbation of chronic bronchitis. The drug has an oral bioavailability of approximately 71%. Approximately 20-35% of gemifloxacin is excreted unchanged in the urine after 24 hours. The elimination half-life of gemifloxacin is 6-8 hours in patients with normal renal function, supporting once-daily dosing. The 24-hour free-drug area under the plasma concentration-time curve:minimum inhibitory concentration ratio (fAUC(0-24):MIC) associated with efficacy, based on results from in vitro and animal models of infection, is approximately 30. With a mean fAUC(0-24) of approximately 3 microg*hour/ml (35% of total AUC(0-24) of 8.4) and a median S. pneumoniae MIC for 90% of tested strains of 0.03, a fAUC(0-24):MIC ratio of 100 would be expected after standard dosing (320 mg once/day). In clinical studies involving both hospitalized and outpatient populations, gemifloxacin has been highly effective in the treatment of community-acquired pneumonia and acute exacerbation of chronic bronchitis. Clinical success rates ranged from 93.9-95.9% in patients with community-acquired pneumonia and 96.1-97.5% in those with acute exacerbation of chronic bronchitis. Gemifloxacin is well tolerated; the frequency of adverse events with this agent is low. Most adverse events are mild-to-moderate in severity, with diarrhea (< 4%), nausea and rash (< 3%), and headache (< 2%) most commonly reported. Drug interactions with gemifloxacin are not common, although absorption is greatly reduced when given with divalent and trivalent cation-containing compounds, such as antacids. Due to its potent activity against many common gram-positive and gram-negative respiratory pathogens, its proven clinical efficacy, and its favorable safety profile, gemifloxacin is a highly effective empiric treatment for community-acquired lower respiratory tract infections.
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Azoulay-Dupuis E, Bédos JP, Mohler J, Moine P, Cherbuliez C, Peytavin G, Fantin B, Köhler T. Activity of gemifloxacin against quinolone-resistant Streptococcus pneumoniae strains in vitro and in a mouse pneumonia model. Antimicrob Agents Chemother 2005; 49:1046-54. [PMID: 15728901 PMCID: PMC549237 DOI: 10.1128/aac.49.3.1046-1054.2005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gemifloxacin is a novel fluoronaphthyridone quinolone with enhanced in vitro activity against Streptococcus pneumoniae. We investigated the activities of gemifloxacin and trovafloxacin, their abilities to select for resistance in vitro and in vivo, and their efficacies in a mouse model of acute pneumonia. Immunocompetent Swiss mice were infected with 10(5) CFU of a virulent, encapsulated S. pneumoniae strain, P-4241, or its isogenic parC, gyrA, parC gyrA, and efflux mutant derivatives (serotype 3); and leukopenic mice were infected with 10(7) CFU of two poorly virulent clinical strains (serotype 11A) carrying either a parE mutation or a parC, gyrA, and parE triple mutation. The drugs were administered six times every 12 h, starting at either 3 or 18 h postinfection. In vitro, gemifloxacin was the most potent agent against strains with and without acquired resistance to fluoroquinolones. While control mice died within 6 days, gemifloxacin at doses of 25 and 50 mg/kg of body weight was highly effective (survival rates, 90 to 100%) against the wild-type strain and against mutants harboring a single mutation, corresponding to area under the time-versus-serum concentration curve at 24 h (AUC(24))/MIC ratios of 56.5 to 113, and provided a 40% survival rate against a mutant with a double mutation (parC and gyrA). A total AUC(24)/MIC ratio of 28.5 was associated with poor efficacy and the emergence of resistant mutants. Trovafloxacin was as effective as gemifloxacin against mutants with single mutations but did not provide any protection against the mutant with double mutations, despite treatment with a high dose of 200 mg/kg. Gemifloxacin preferentially selected for parC mutants both in vitro and in vivo.
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Owens RC, Bhavnani SM, Ambrose PG. Assessment of pharmacokinetic-pharmacodynamic target attainment of gemifloxacin against Streptococcus pneumoniae. Diagn Microbiol Infect Dis 2005; 51:45-9. [PMID: 15629228 DOI: 10.1016/j.diagmicrobio.2004.08.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2004] [Accepted: 08/30/2004] [Indexed: 10/26/2022]
Abstract
The treatment of community-acquired respiratory tract infections has been complicated by the emergence of multidrug-resistant Streptococcus pneumoniae. Although traditionally rare, a growing concern for fluoroquinolone-resistant pneumococci has surfaced. More pharmacodynamically potent antimicrobial agents are clearly needed, as the use of such agents may further optimize clinical and microbiological outcomes for patients and slow the emergence of fluoroquinolone resistance. For fluoroquinolones, the ratio of the 24-h area under the concentration-time curve of the agent to the minimum inhibitory concentration of the agent against the pathogen for the fraction of unbound drug is the major pharmacokinetic-pharmacodynamic (PK-PD) measure correlating with efficacy in nonclinical models and infected patients. A 2500-patient Monte Carlo simulation, utilizing a patient-population pharmacokinetic model derived from phase 3 registration trials and the minimum inhibitory concentration distribution for gemifloxacin against 3117 clinical strains of S. pneumoniae, was carried out to estimate the probability of gemifloxacin attaining exposures associated with efficacy. The overall probability PK-PD target attainment for gemifloxacin was greater than 0.99. Gemifloxacin is among the most pharmacodynamically potent fluoroquinolones and is more potent than ciprofloxacin, ofloxacin, and levofloxacin. Preferential use of pharmacodynamically potent agents over other alternatives may lead to improved clinical outcomes and decreased selection of fluoroquinolone-resistant pneumococci.
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Islinger F, Bouw R, Stahl M, Lackner E, Zeleny P, Brunner M, Müller M, Eichler HG, Joukhadar C. Concentrations of gemifloxacin at the target site in healthy volunteers after a single oral dose. Antimicrob Agents Chemother 2004; 48:4246-9. [PMID: 15504848 PMCID: PMC525435 DOI: 10.1128/aac.48.11.4246-4249.2004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2004] [Revised: 05/24/2004] [Accepted: 07/20/2004] [Indexed: 11/20/2022] Open
Abstract
Free gemifloxacin concentrations in the interstitial space fluid of skeletal muscle and subcutaneous adipose tissue were measured by means of in vivo microdialysis to characterize the ability of gemifloxacin to penetrate human soft tissues. Twelve healthy volunteers received a single oral dose of 320 mg of gemifloxacin. The mean areas under the concentration-time curves from 0 to 10 h (AUC(0-10)) were significantly higher for soft tissue than for unbound gemifloxacin in plasma (P < 0.05). The ratios of the mean AUC(0-10) for tissue to the AUC(0-10) for free gemifloxacin in plasma were 1.7 +/- 0.7 (mean +/- standard deviation) for skeletal muscle and 2.4 +/- 1.0 for adipose tissue. The AUC(0-24) ratios for free gemifloxacin in tissues to the MIC at which 90% of frequently isolated bacteria are inhibited were close to or higher than 100 h. Therefore, based on pharmacokinetic and pharmacodynamic calculations, we conclude that gemifloxacin might be a useful therapeutic option for the treatment of soft tissue infections.
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Coleman PJ, Brashear KM, Askew BC, Hutchinson JH, McVean CA, Duong LT, Feuston BP, Fernandez-Metzler C, Gentile MA, Hartman GD, Kimmel DB, Leu CT, Lipfert L, Merkle K, Pennypacker B, Prueksaritanont T, Rodan GA, Wesolowski GA, Rodan SB, Duggan ME. Nonpeptide alphavbeta3 antagonists. Part 11: discovery and preclinical evaluation of potent alphavbeta3 antagonists for the prevention and treatment of osteoporosis. J Med Chem 2004; 47:4829-37. [PMID: 15369386 DOI: 10.1021/jm049874c] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
3-(S)-Pyrimidin-5-yl-9-(5,6,7,8-tetrahydro-[1,8]naphthyridin-2-yl)-nonanoic acid (5e) and 3-(S)-(methylpyrimidin-5-yl)-9-(5,6,7,8-tetrahydro-[1,8]naphthyridin-2-yl)-nonanoic acid (5f) were identified as potent and selective antagonists of the alpha(v)beta(3) receptor. These compounds have excellent in vitro profiles (IC(50) = 0.07 and 0.08 nM, respectively), significant unbound fractions in human plasma (6 and 4%), and good pharmacokinetics in rat, dog, and rhesus monkey. On the basis of the efficacy shown in an in vivo model of bone turnover following once-daily oral administration, these two compounds were selected for clinical development for the treatment of osteoporosis.
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Babalola CP, Scriba GKE, Sowunmi A, Alawode OA. Liquid chromatographic determination of pyronaridine in human plasma and oral dosage form. J Chromatogr B Analyt Technol Biomed Life Sci 2004; 795:265-72. [PMID: 14522031 DOI: 10.1016/s1570-0232(03)00591-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A new procedure for the determination of pyronaridine in plasma by reversed-phase high performance liquid chromatography (HPLC) with UV detection at 278 nm is described. The method involves liquid-liquid extraction of the drug with diethyl ether following basification of the deproteinized plasma with alkaline phosphate buffer. Chromatographic separation was achieved using a microbore C-18 column and a mobile phase consisting of 0.1% aqueous trifluoroacetic acid (TFA)-acetonitrile (75:25% (v/v)), pH 2.2, at a flow rate of 0.07 ml/min. Papaverine was used as internal standard. The response was linear between 50 and 1500 ng/ml. The limit of quantitation (LOQ) after plasma extraction was 50 ng/ml, the intra- and inter-day precision ranged from 2.5 to 13.8% (CV). The recovery of the drug from plasma and accuracy were >90%. Preliminary application of the method for monitoring pyronaridine in humans upon oral administration of the tablet demonstrated the principal usefulness of the assay for clinical trial studies. The method can also be used to analyze the compound in pharmaceutical formulations.
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Yoo BK, Triller DM, Yong CS, Lodise TP. Gemifloxacin: a new fluoroquinolone approved for treatment of respiratory infections. Ann Pharmacother 2004; 38:1226-35. [PMID: 15187209 DOI: 10.1345/aph.1e003] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE To evaluate the microbiology, pharmacokinetic parameters, drug interactions, and results of the available clinical trials of gemifloxacin for the treatment of community-acquired pneumonia (CAP) and acute exacerbation of chronic bronchitis (AECB). DATA SOURCES MEDLINE (1966-September 2003) was searched for primary and review articles. Data from the manufacturer were also included. Key words included adverse effects, clinical trials, drug interactions, gemifloxacin, and pharmacokinetic parameters. STUDY SELECTION AND DATA EXTRACTION All articles and product labeling concerning gemifloxacin, a fluoroquinolone antibiotic recently approved by the Food and Drug Administration for treatment of CAP and AECB, were included for review. DATA SYNTHESIS Compared with currently available fluoroquinolones, gemifloxacin demonstrated improved in vitro activity against Streptococcus pneumoniae (minimum inhibitory concentration for 90% eradication 0.03 microg/mL) and similar activity against gram-negative respiratory pathogens (Haemophilus influenzae, Moraxella catarrhalis) and atypical pathogens such as Chlamydia pneumoniae, Legionella pneumophila, and Mycoplasma pneumoniae. Gemifloxacin, consistent with other available fluoroquinolones, has insufficient activity against methicillin-resistant Staphylococcus aureus to allow clinical use for such infections. Gemifloxacin has adequate bioavailability and a favorable drug interaction profile. Gemifloxacin was comparable to commonly employed nonfluoroquinolone regimens for treatment of CAP and AECB, although the studies were designed to demonstrate equivalence. Gemifloxacin once daily for 5-7 days was well tolerated in controlled and uncontrolled clinical studies. Available clinical data, however, are insufficient to draw clinical or toxicologic distinctions between gemifloxacin and other fluoroquinolones. CONCLUSIONS Gemifloxacin may be a suitable choice for empiric treatment of CAP or AECB. However, due to the significant history of fluoroquinolone-induced hepatic failure and dermatologic complications, the use of this drug should be closely monitored.
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Malerczyk C, Kolbert M, Kinzig-Schippers M, Sörgel F, Machka K, Shah PM. Serum bactericidal activity of gemifloxacin versus clarithromycin against Streptococcus pneumoniae with different susceptibility to quinolones. J Chemother 2004; 16:56-61. [PMID: 15078000 DOI: 10.1179/joc.2004.16.1.56] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The objective of this study was to determine serum bactericidal titers (SBT, the highest dilution of serum showing no growth) and the serum bactericidal activity (SBA, i.e. duration of SBT greater than 1:2) as well as the serum bactericidal rate of gemifloxacin and clarithromycin after single doses in healthy male volunteers against Streptococcus pneumoniae. Strains tested had various degrees of susceptibility to penicillin as well as different susceptibility to quinolones due to a different QRDR mutation pattern (parC, gyrA). Serum samples from volunteers (n = 12) who had received a single oral dose of either 320 mg gemifloxacin or 500 mg clarithromycin in an open-label crossover study were obtained over a 24-hour period. SBA was determined, using the microdilution method. SBA of wildtype strains for gemifloxacin ranged from 8.9 to 15.4 h (mean 12.6 h). For gemifloxacin, 2 strains with solitary gyrA mutation had an SBA from 4.5 to 4.7 h (median 4.5 h). One of the 2 strains with a single QRDR mutation in parC displayed an SBA of 4.5 h, comparable to the gyrA mutation strains, whereas the second strain had a nearly twice as long SBA of 8.9 h. Two strains with two mutations (parC and gyrA) did not display any SBA. For clarithromycin, the duration of SBA ranged from 11.3 to 15.5 h (mean 13.6 h) for 6 of the 12 strains with an MIC < or = 0.06 mg/L (no SBA was found for the remaining strains, with an MIC of 0.25 mg/L or higher). In conclusion, a correlation between individual serum concentrations and SBA was found for both antibiotics.
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Mise M, Yadera S, Matsuda M, Hashizume T, Matsumoto S, Terauchi Y, Fujii T. POLYMORPHIC EXPRESSION OF CYP1A2 LEADING TO INTERINDIVIDUAL VARIABILITY IN METABOLISM OF A NOVEL BENZODIAZEPINE RECEPTOR PARTIAL INVERSE AGONIST IN DOGS. Drug Metab Dispos 2004; 32:240-5. [PMID: 14744947 DOI: 10.1124/dmd.32.2.240] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
5-(3-methoxyphenyl)-3-(5-methyl-1,2,4-oxadiazol-3-yl)-2-oxo-1,2-dihydro-1,6-naphthyridine (AC-3933) is a novel cognitive enhancer with central benzodiazepine receptor partial inverse agonistic activity. AC-3933 is predominantly metabolized to hydroxylated metabolite [SX-5745; 3-(5-hydroxymethyl-1,2,4-oxadiazol-3-yl)-5-(3-methoxyphenyl)-2-oxo-1,2-dihydro-1,6-naphthyridine] in dog. Initially, we found that there is considerable interindividual variability in AC-3933 hydroxylation in dogs and that dogs could be phenotyped as extensive metabolizer (EM) and poor metabolizer (PM). Then, to clarify the cause of AC-3933 polymorphic hydroxylation in dogs, in vitro studies were carried out using liver microsomes from EM and PM dogs. Our results show that AC-3933 hydroxylation clearance in PM dogs was much lower than that in EM dogs (0.2 versus 10.8-20.5 microl/min/mg, respectively). In addition, AC-3933 hydroxylation was significantly inhibited by alpha-naphthoflavone, a CYP1A inhibitor, and by anti-CYP1A2 antibodies, indicating that CYP1A2 was responsible for the polymorphic hydroxylation of AC-3933 in dogs. Furthermore, immunoblotting results have shown that although CYP1A2 protein was not detected in PM dogs (<0.86 pmol/mg), CYP1A2 content in EM dogs was prominent (6.1-13.0 pmol/mg). These results indicate that AC-3933 polymorphic hydroxylation arises from the polymorphic expression of CYP1A2 in dogs, which might involve genetic polymorphism of the CYP1A2 gene.
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Firsov AA, Zinner SH, Lubenko IY, Portnoy YA, Vostrov SN. Simulated in vitro quinolone pharmacodynamics at clinically achievable AUC/MIC ratios: advantage of I E over other integral parameters. Chemotherapy 2004; 48:275-9. [PMID: 12673102 DOI: 10.1159/000069709] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To compare the antimicrobial effects of clinically achievable ratios of area under the curve (AUC) to MIC, a clinical isolate of Moraxella catarrhalis was selected with MICs corresponding to the MIC(50)s of four quinolones. Monoexponentially declining concentrations observed in human plasma after oral administration of 1,000 mg of ciprofloxacin (as two 500-mg doses at a 12-hour interval), 320 mg gemifloxacin, 500 mg levofloxacin or 400 mg moxifloxacin (each as a single dose) and were simulated in an in vitro dynamic model. The respective half-lives were 4, 7.4, 6.8 and 12.1 h, and the AUC/MICs were 730, 1,130, 920 and 690 h. The time-kill/regrowth curves yielded similar patterns with the four quinolones: a rapid reduction in bacterial numbers followed by bacterial regrowth that occurred later with moxifloxacin than with ciprofloxacin, gemifloxacin, and levofloxacin. The total antimicrobial effect of moxifloxacin as expressed by the I(E) parameter (area between the control growth and time- kill curves from time zero to the time when bacterial counts on the regrowth curve achieve the same maximal numbers as in the absence of antimicrobial) was 30, 55, and 120% greater than gemifloxacin, levofloxacin and ciprofloxacin, respectively. Unlike I(E), the other integral indices determined over a fixed time (24 h) - the area between the control growth and time-kill curves, area above the time-kill curve and area under the time-kill curve were similar for the four fluoroquinolones, thus precluding their differentiation.
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Barequet IS, Denton P, Osterhout GJ, Tuli S, O'Brien TP. Treatment of Experimental Bacterial Keratitis With Topical Trovafloxacin. ACTA ACUST UNITED AC 2004; 122:65-9. [PMID: 14718297 DOI: 10.1001/archopht.122.1.65] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To investigate the therapeutic role of trovafloxacin mesylate, a newer-generation fluoroquinolone with an expanded spectrum of activity, in the treatment of experimental bacterial keratitis. METHODS Susceptibility studies were performed on various strains of ocular isolates to determine the minimum inhibitory concentration (MIC) of trovafloxacin compared with ciprofloxacin and ofloxacin, using the E-test method. Pharmacokinetic studies were performed by a single topical administration of trovafloxacin to rabbit eyes with either an intact or denuded corneal epithelium. Aqueous humor, vitreous, and corneal concentrations of trovafloxacin were determined at different time points. Experimental bacterial keratitis studies were performed in rabbit eyes. Three identical studies were conducted using Staphylococcus aureus, Streptococcus pneumoniae, or Pseudomonas aeruginosa. Therapy groups included 0.5% trovafloxacin, 0.3% ciprofloxacin, 0.3% ofloxacin, and isotonic sodium chloride solution. After 12 hours of drops administration, corneas were excised, homogenized, and serially plated. The main outcome measure was quantitative bacteriologic analysis for residual colony-forming units. RESULTS In vitro susceptibility study findings indicated that the MIC of trovafloxacin was significantly lower than the MIC of ciprofloxacin and ofloxacin for S. aureus, S. pneumoniae, and Haemophilus influenzae, lower than the MIC of ciprofloxacin and ofloxacin for Staphylococcus epidermidis, and intermediate between ciprofloxacin and ofloxacin for P. aeruginosa. Pharmacokinetic studies showed a significant concentration of trovafloxacin in the treated corneas, especially in eyes with a denuded epithelium. All serum samples had undetectable trovafloxacin concentrations. Experimental keratitis studies showed a statistically significant decrease of colony-forming units in trovafloxacin-treated eyes in the S. aureus model and a similar decrease in the S pneumoniae and P aeruginosa models. CONCLUSIONS Topical 0.5% trovafloxacin proved to be an effective ocular medication for the therapy of gram-positive and gram-negative keratitis. Clinical Relevance Trovafloxacin may provide an excellent therapeutic alternative in bacterial keratitis.
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Prueksaritanont T, Fernandez-Metzler C, Meng Y, Barrish A, Halczenko W, Rodan SB, Hutchinson JH, Duggan ME, Lin JH. Disposition of a novel and potent alpha(v)beta3 antagonist in animals, and extrapolation to man. Xenobiotica 2004; 34:103-15. [PMID: 14742139 DOI: 10.1080/713767592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
1. The disposition of 3-[2-oxo-3-[3-(5,6,7,8-tetrahydro-[1,8]naphthyridin-2-yl) propyl]-imidazolidin-1-yl]-3(S)-(6-methoxy-pyridin-3-yl)propionic acid (compound A), a potent and selective alpha(v)beta(3) antagonist, was characterized in several animal species in support of its selection for preclinical safety studies and potential clinical development. 2. Compound A exhibited marked species differences in pharmacokinetics; the plasma clearances and bioavailabilities ranged from 33-47 ml min(-1) kg(-1) in rats and mice to 4-9 ml min(-1) kg(-1) in dogs and monkeys, and about 20% in rats to 70-80% in dogs and monkeys, respectively. Both the intravenous (i.v.) and oral kinetics of compound A were linear over the dose range studied in dogs (0.1-5 mg kg(-1) i.v. and 0.25-20 mg kg(-1) orally [p.o.]) and rats (1-30 mg kg(-1) i.v. and 4-160 mg kg(-1) p.o.). 3. Compound A was eliminated substantially by urinary excretion; the urinary recovery of the unchanged drug was 67% in rhesus, 48% in dogs and about 30% in rats. In these animal species, biotransformation was modest. 4. Following i.v. administration of [(14)C]-compound A to rats, the radioactivity rapidly distributed to all tissues investigated, with high levels of the radioactivity detected in liver, kidney and intestine soon after the drug administration. The radioactivity declined rapidly, with less than 1% of the i.v. dose remaining at 30-h post-dose. 5. Compound A was moderately bound to plasma proteins, with unbound fractions of 26, 20, 14 and 5% for rats, dogs, monkeys and humans, respectively. It was bound primarily to human alpha(1)-acid glycoprotein (about 85% binding at 0.1% concentration), as compared with human albumin (< 50% binding at 4% concentration). 6. Using simple allometry, compound A was predicted to exhibit relatively low clearance (1-3 ml min(-1) kg(-1)) and low volume of distribution (0.1-0.3 l kg(-1)) in humans. Based on the predicted values, compound A was projected to exhibit a favourable oral pharmacokinetic profile in humans, with good bioavailability (50-80%). These predicted values provided a basis for compound selection for further development.
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Garrison MW, Schimmels JA, Madaras-Kelly KJ. In vitro pharmacodynamic activity of gatifloxacin, gemifloxacin, moxifloxacin and levofloxacin against Streptococcus pneumoniae containing specific mutations in DNA gyrase and topoisomerase IV. Diagn Microbiol Infect Dis 2003; 47:587-93. [PMID: 14711480 DOI: 10.1016/s0732-8893(03)00152-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
An in vitro pharmacodynatnic modeling apparatus (PDMA) generated specific bacterial kill profiles for single-dose regimens of gatifloxacin (GT), gemifloxacin (GM), moxifloxacin (MX) and levofloxacin (LV) against isolates of Streptococcus pneumoniae with specific QRDR profiles: SP-WT (no modifications); SP-C (changes in parC); and SP-AC (changes in both parC and gyrA). No differences in 3-log reduction time or total log reduction were observed among the four agents for SP-WT; however, LV failed to achieve a 3-log reduction in SP-C and SP-AC, and total log reduction after 12 hrs was minimal compared to the other agents. GM and MX required less time for 3-log reduction of SP-AC compared to GT, but total log reductions in SP-AC were similar among the three newer quinolone agents (GM > MX > GT). The study isolates with QRDR modifications greatly reduced LV activity. GM and MX maintained the greatest degree of activity against all study isolates and their activity was not adversely influenced by the genetic modifications in SP-C and SP-AC. The dual targeting characteristic of GM was also assessed, but did not offer significant advantages relative to MX and GT.
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