Reference

Bacterial resistance to LB20304, a new fluoroquinolone antibiotic

Bacterial resistance to LB20304, a new fluoroquinolone antibiotic. Kim, Mu-Yong; Paek, Kyoung-Sook; Kim, In-Chull; Kwak, Jin-Hwan ( Biotech Res. Inst., LG Chemical Ltd., Taejon 305-380, S. Korea). Archives of Pharmacal Research, 19(5), 400-405 (English) 1996 Pharmaceutical Society of Korea. CODEN: APHRDQ. ISSN: 0253-6269. DOCUMENT TYPE: Journal CA Section: 10 (Microbial, Algal, and Fungal Biochemistry) In vitro studies were conducted to det. the frequency rate of spontaneous resistance to LB20304 and to det. whether cross-resistance to other antimicrobial agents develops. In eight strains of bacteria, the frequency of mutation at LB20304 concns. of four and eight times the minimal inhibitory concn. (MIC) ranged from less than 4.0 ′ 10-10 to 2.2 ′ 10-8. These results were similar to those found for other new fluoroquinolones. The development of stepwise resistance was detd. by repeated subculture in broth in the presence of increasing concns. of the compds. Exposure of bacteria to increasing concns. of LB20304 resulted in the selection of organisms with higher MICs. There were 4- to 128-fold increases in the MIC of LB20304 for Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli and Pseudomonas aeruginosa strains. 175463-14-6 and 85721-33-1 are just another two chemicals used in this study. However, those strains selected after repeated exposure were well with the susceptibility range for LB20304 except for Pseudomonas aeruginosa. The resistant isolates selected with LB20304 showed cross-resistance when tested against ciprofloxacin and vice versa. .

High-performance liquid chromatographic assay of a new fluoroquinolone, LB 20304a, in the plasma of rats and dogs

High-performance liquid chromatographic assay of a new fluoroquinolone, LB 20304a, in the plasma of rats and dogs. Seo, Mi-Kyeong; Jeong, Yi-Na; Kim, Hoon-Joo; Kim, In-Chull; Lee, Yong-Hee (LG Chem Biotech Research Institute, Taejon 305-380, S. Korea). Archives of Pharmacal Research, 19(6), 554-558 (English) 1996 Pharmaceutical Society of Korea. CODEN: APHRDQ. ISSN: 0253-6269. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacology) High-performance liq. chromatog.Chemical with cas number 175463-14-6 also plays role. method was developed for the detn. of LB 20304a in the plasma of rats and dogs. The analyte was deproteinized with 1 vol. of methanol and 1/2 vol. of 10% zinc sulfate, and the supernatant was injected onto a reversed-phase HPLC column. The mobile phase was a mixt. of 24 parts of acetonitrile and 76 parts of 0.1% trifluoroacetic acid. The flow rate was 1 mL/min, and the effluent was monitored by fluorescence detector at an excitation wavelength of 337 nm and an emission wavelength of 460 nm. The retention time of LB 20304a was 6.3 min. The assay of was linear over the LB 20304a concn. range of 0.2-100 mg/mL in the plasma of rats and dogs. The lower limit of quantification was 0.2 mg/mL using 100 mL of plasma with a 97-99% accuracy and a 12-14% precision. In the 0.5, 5, and 50 mg/mL quality control samples, the intra- and inter-day accuracy were 88-95% and 88-97%, whereas intra- and interday precision were 0.5-6.6% and 0.2-9.3%, resp., in the plasma of rats and dogs. The recoveries were 68-71% independent of concn. and species in the plasma. No interferences from endogenous substances were obsd. Taken together, the above HPLC assay method by deproteinization and fluorescence detection was suitable for the detn. of LB 20304a in the preclin. pharmacokinetics. .