Interspecies scaling of excretory amounts using allometry - retrospective analysis with rifapentine, aztreonam, carumonam, pefloxacin, miloxacin, trovafloxacin, doripenem, imipenem, cefozopran, ceftazidime, linezolid for urinary excretion and rifapentine, cabotegravir, and dolutegravir for fecal excretion.

1. Interspecies allometry scaling for prediction of human excretory amounts in urine or feces was performed for numerous antibacterials. Antibacterials used for urinary scaling were: rifapentine, pefloxacin, trovafloxacin (Gr1/low; <10%); miloxacin, linezolid, PNU-142300 (Gr2/medium; 10-40%); aztreonam, carumonam, cefozopran, doripenem, imipenem, and ceftazidime (Gr3/high; >50%). Rifapentine, cabotegravir, and dolutegravir was used for fecal scaling (high; >50%). 2. The employment of allometry equation: Y = aW(b) enabled scaling of urine/fecal amounts from animal species. Corresponding predicted amounts were converted into % recovery by considering the respective human dose. Comparison of predicted/observed values enabled fold difference and error calculations (mean absolute error [MAE] and root mean square error [RMSE]). Comparisons were made for urinary/fecal data; and qualitative assessment was made amongst Gr1/Gr2/Gr3 for urine. 3. Average correlation coefficient for the allometry scaling was >0.995. Excretory amount predictions were largely within 0.75- to 1.5-fold differences. Average MAE and RMSE were within ±22% and 23%, respectively. Although robust predictions were achieved for higher urinary/fecal excretion (>50%), interspecies scaling was applicable for low/medium excretory drugs. 4. Based on the data, interspecies scaling of urine or fecal excretory amounts may be potentially used as a tool to understand the significance of either urinary or fecal routes of elimination in humans in early development.

Terbium chelates for fluorescence immunoassays.

The sensitization of terbium(III) ion luminescence in the presence of 1-ethyl-14-dihydro-6,7-methylenedioxy-4-oxoquinoline-3-carboxylic (oxolinic) acid was studied. The terbium label is bound to the antibody with diethylenetriamine-pentaacetic acid anhydride (DTPAA). Optimum luminescence intensity is observed at pH 7.5 and the luminescence significantly increases in the presence of cationic surfactant, cetyltrimethylammonium bromide. The sensitivity of Tb(III) detection is 5 x 10(14) mol l(-1). This luminescence system is proposed for time-resolved fluoroimmunoassay.

High-performance liquid chromatographic method for the rapid and simultaneous determination of sulfamonomethoxine, miloxacin and oxolinic acid in serum and muscle of cultured fish.

A rapid method for the simultaneous determination of sulfamonomethoxine (SMM), miloxacin (MLX) and oxolinic acid (OA) in serum and muscle of cultured fish by high-performance liquid chromatography has been developed. A Hisep shielded hydrophobic phase column (15 cm x 4.6 mm I.D.) and a mobile phase of 0.05 M citric acid-0.2 M disodium hydrogenphosphate buffer, pH 2.5 in 10 mM tetra-n-butyl ammonium bromide-acetonitrile (85:15) with ultraviolet detection at 265 nm were used. The recoveries of SMM, MLX and OA from serum and muscle samples were 72-101%. The detection limits of the three drugs were 0.05-0.1 microgram/ml or g of sample.

Structure-activity relationships among DNA gyrase inhibitors. Synthesis and biological evaluation of 1,2-dihydro-4, 4-dimethyl-1-oxo-2-naphthalenecarboxylic acids as 1-carba bioisosteres of oxolinic acid.

A series of oxolinic acid analogues was synthesized in an attempt to evaluate the role, if any, played by the N-1 atom in putative modes of action of antimicrobial DNA gyrase inhibitors. Carba analogues were prepared because these have no possibility of an internal resonance contribution of the nitrogen atom and yet could otherwise satisfy electronic requirements of putative modes of action. Successful routes were developed involving Friedel-Craft's cycloaddition of suitable aromatic compounds with 4,4-dimethylbutyrolactone, followed by ethoxycarbonylation, oxidation with dichlorodicyanobenzoquinone, and careful saponification. The gem-dimethyl group of these analogues prevents aromatization at the cost of nonplanarity. Only the unsubstituted parent compound, 1,2-dihydro-4,4-dimethyl-1-oxo-2-naphthalenecarboxylic acid, possessed any appreciable antimicrobial activity in vitro. This may be due to a different mode of action, however, since gave no measurable inhibition of DNA gyrase in vitro. Thus, the N-1 atom plays a significant role in enzymic and bacteriological inhibition that cannot be compensated for by the presence of C-6 oxygen atoms.

[Chemotherapy on the biliary tract infections. XIII. Miloxacin, a novel chemotherapeutic agent, its excretion into bile and clinical effect on the biliary tract infections (author's transl)].

Miloxacin, a novel chemotherapeutic agent, has been reported to have very potent antibacterial activity to E. coli, Klebsiella, Proteus and other Gram-negative rods and be excreted into bile at high levels. Therefore, the effectiveness of miloxacin against biliary tract infections and its excretion into bile in patients were investigated. The results were as follows: i) Comparative studies on the excretion of miloxacin, nalidixic acid (NA) and cephalexin (CEX) into bile of patients operated in gallbladder were performed by a crossover method. The maximum concentration of miloxacin after oral administration of 500 mg ranged from 18.2 to 24.0 micrograms/ml and were much higher than those of NA (5.3 micrograms/ml) and CEX (3.4 micrograms/ml). The mean recovery of miloxacin within 6 hours was 0.256% and much greater than those of NA (0.075%) and CEX (0.027%). ii) Into bile, intact miloxacin and its metabolites (the glucuronides of miloxacin and M-2) were excreted but M-1 was scarcely excreted. Regression analysis of the concentrations by the bioassay compared with those intact miloxacin by the HPLC method gave a good correlation with r = 0.96. iii) The clinical effectiveness against the biliary tract infections was investigated in 29 cases. Miloxacin showed the excellent effect in 8 cases and the good effect in 17 cases, giving an effective ratio of 86.2%. Especially, all of the cases dosed with miloxacin over 34 mg/kg in a day showed excellent or good results. iv) The rates of clinical effectiveness were 85.7, 80.0% and 71.4% in E. coli, Klebsiella and Proteus infections, respectively. The antibacterial activity of miloxacin against 27 strains isolated in this test was more potent than those of NA and CEX. v) During the clinical tests, none of any side effect with miloxacin was observed in both of subjective and objective symptoms. These results show that miloxacin is expected to be fully applicable on the therapy of biliary tract infections.

[Absorption, distribution, excretion, and metabolism of 14C-miloxacin in female rats (author's transl)].

Absorption, distribution, excretion, and metabolism of 5,8-dihydro-5-methoxy-8-oxo-2H-1, 3-dioxolo[4,5-g]quinoline-7-carboxylic acid(miloxacin), a new antimicrobial agent, were studied in female rats by using 14C-miloxacin which was administered orally to the animals in a dose of 50 mg/kg. 14C-Miloxacin was absorbed rather fast and the radioactivity of 14C distributed widely in a variety of tissues. Peak concentrations of 14C in serum and tissues occurred 1 to 2 hr after dosing, and were approximately 60 micrograms equivalent of miloxacin per ml or g in serum, liver and kidney. Excretion of 14C in urine and feces was fast, and recoveries of 14C during 48 hr period were approximately 30% in urine and 60% in feces. Concentrations of intact 14C-miloxacin were higher in serum and kidney while lower in liver. Major metabolites in excreta were the demethoxy derivative (M-1) and the glucuronide of miloxacin; and as minor metabolites five other metabolites were identified. As sex differences, the following facts were observed; concentrations of 14C in serum and tissues were generally 1.2 to 1.6 times higher in female rats those in male rats, and the capacity to metabolize miloxacin, especially in the glucuronic acid conjugation, was rather lower in female rats than that in male rats.

Antibacterial activity of miloxacin.

The chemotherapeutic properties of miloxacin (5,8-dihydro-5-methoxy-8-oxo-2H-1,3-dioxolo-[4,5-g]quinoline-7-carboxylic acid) have been compared with those of oxolinic acid and nalidixic acid. The in vitro activities of miloxacin (minimum inhibitory concentrations) against a variety of gram-negative bacteria, especially Enterobacteriaceae and Haemophilus, were comparable to those of oxolinic acid and 8 to 16 times greater than those of nalidixic acid. Miloxacin was more active than oxolinic acid against some anaerobes and less active against staphylococci. Miloxacin exhibited significant activities when administered orally to mice infected with Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Proteus vulgaris, or Serratia marcescens. Its efficacy was comparable to that of oxolinic acid and two to four times greater than that of nalidixic acid. Miloxacin was less active against a Pseudomonas aeruginosa infection and inactive at the maximum test doses against a Streptococcus pyogenes infection.

Absorption and excretion of miloxacin in mice, rats, and dogs.

Miloxacin, a synthetic antibacterial agent structurally related to oxolinic acid, has a broad spectrum of activity in vitro against gram-negative bacteria and considerable activity in vivo against infections with these bacteria. These observations led to studies on the absorption and excretion of miloxacin in mice, rats, and dogs after administration of a single oral dose. Studies on oxolinic acid have been included for comparison. Peak serum levels of miloxacin, attained 1 h after administration of 20, 50, and 100 mg/kg to rats and dogs, were approximately 20, 40, and 60 micrograms/ml, respectively. Peak levels in mice receiving the same dose were 15, 60, and 80 micrograms/ml at 0.5 h. Peak serum levels of oxolinic acid were attained 0.5 to 1 h later than the above times at comparable doses and were one-half to one-fourth those of miloxacin. Urinary recovery of miloxacin at the above doses ranged from 3.2 to 6.5% during the 24-h posttreatment period. Recoveries of oxolinic acid were one-half to one-fifth those of miloxacin. At a 50-mg/kg dose, rats excreted 4.6% of the miloxacin in bile in the 20-h posttreatment period.

Determination of miloxacin and metabolites in human serum and urine by high-pressure liquid chromatography.

A sensitive and reliable high-pressure liquid chromatography (HPLC) assay for miloxacin and its two principal metabolites, 5,8-dihydro-8-oxo-2H-1,3-dioxolo[4,5-g]quinoline-7-carboxylic acid (M-1) and 1,4-dihydro-1,6-dimethoxy-7-hydroxy-4-oxoquinoline-3-carboxylic acid (M-2), in human serum and urine was developed. A strong anion-exchange Zipax SAX column using a mobile phase of 0.01 M citric acid solution containing 0.03 M sodium nitrate with pH 5.0 was used to achieve separation of the three compounds. The retention times of miloxacin, M-1, and M-2 were 3.8, 9.3, and 5.9 min, respectively. Serum and urine concentrations of these compounds as low as 10 ng/ml were measured. When results from the HPLC assay were compared with those from the microbiological assay of serum and urine samples from human subjects receiving miloxacin orally, the correlation coefficients were 0.94 for the serum and 0.99 for the urine. The HPLC assay method presents an alternative to the microbiological assay and permits future pharmacokinetic investigations of miloxacin.

Mode of action of a new nalidixic acid derivative, AB206.

A new chemotherapeutic agent, AB206, shows potent antibacterial activity against gram-negative bacteria, including most of the nalidixic acid-resistant strains tested. It strongly inhibits deoxyribonucleic acid (DNA) synthesis in Escherichia coli, but only slightly inhibits ribonucleic acid and protein synthesis. Its activity on DNA synthesis in vivo and in vitro is greater than that of nalidixic acid. AB206 also strongly inhibits in vivo DNA synthesis in nalidixic acid-susceptible and -resistant clinical isolates of Proteus and Serratia. AB206 shows high penetrability into E. coli cells, as demonstrated by antibacterial activity with or without ethylenediaminetetraacetic acid, inhibition of in vivo and in vitro DNA synthesis, and uptake of the drug into cells, as compared to nalidixic acid. It appears that the high antibacterial activity of AB206 may be explained both by its potent inhibitory action against DNA synthesis and also by its high penetrability into bacterial cells.

In vitro and in vivo antibacterial activity of AB206, a new naphthyridine derivative.

AB206 (5,8-dihydro-5-methoxy-8-oxo-2H-1,3-dioxolo-4,5-g quinoline 7-carboxylic acid) is a novel antibacterial agent structurally related to nalidixic acid. AB206 has potent antibacterial activity against clinical isolates of gram-negative bacteria and is 4 to 18 times more active than nalidixic acid. AB206 inhibited the growth of Staphylococcus aureus and Pseudomonas aeruginosa, which were resistnat to nalidixic acid. Cross-resistance was not observed between AB206 and various antibiotics, and most bacterial strains resistant to nalidixic acid were susceptible to AB206. AB206 showed bactericidal activity against Escherichia coli, Proteus, Klebsiella pneumoniae, and P. aeruginosa. Chemotherapeutic effects after oral administration of AB206 in mice experimentally infected with E. coli, K. pneumoniae, and Proteus morganii showed that AB206 was two to four times more potent than nalidixic acid.

Quinolone antimicrobial agents. 2. Methylenedioxy positional isomers of oxolinic acid.

The synthesis and antimicrobial activity of the methylenedioxy positional isomers, 1-ethyl-1,4-dihydro-5,6-methylenedioxy-4-oxo-3-quinolinecarboxylic acid (9) and 1-ethyl-1,4-dihydro-7,8-methylenedioxy-4-oxo-3-quinolinecarboxylic acid (17), of oxolinic acid (18) have been accomplished. Isomer 9 was prepared by the reaction of N-ethyl-6,7-methylenedioxyisatoic anhydride with sodioethyl formylacetate [L. A. Mitscher, H. E. Gracey, G. W. Clark III, and T. Suzuki, J. Med. Chem., 21, 485 (1978)], while isomer 17 was prepared by thermal cyclization of diethyl 2-[(2,3-methylenedioxyanilino)methylene]malonate [D. Kaminsky and R. I. Meltzer, J. Med. Chem., 11, 160 (1968)]. Both of the new isomers are less active in vitro when compared to oxolinic acid (18) itself.

[Metabolism of 14C-miloxacin in rats--metabolites in urine, bile and feces (author's transl)].

Isolation and characterization of metabolites of miloxacin, a new antimicrobial agent, were undertaken with rats. 14C-Miloxacin was orally administered to Sprague-Dawley rats at a dose of 50 mg/kg, and urine, bile and feces were collected. The metabolites extracted from the biological samples were isolated by column and thin-layer chromatographies. Characterization of the isolated metabolites was carried out by comparison with the authentic materials in various physicochemical analyses. Eight metabolites together with intact miloxacin were identified; containing the metabolites of N-demethoxy (M-1), catechol (M-3) and 6-methoxy (M-2 and M-4) types and their conjugates with glucuronic acid.