Removal of amoxicillin and cefuroxime axetil by advanced membranes technology, activated carbon and micelle-clay complex.

Two antibacterials, amoxicillin trihydrate and cefuroxime axetil spiked into wastewater were completely removed by sequential wastewater treatment plant's membranes, which included activated sludge, ultrafiltration (hollow fibre and spiral wound membranes with 100 and 20 kDa cut-offs), activated carbon column and reverse osmosis. Adsorption isotherms in synthetic water which employed activated carbon and micelle-clay complex (octadecyltrimethylammonium-montmorillonite) as adsorbents fitted the Langmuir equation. Qmax of 100 and 90.9 mg g(-1), and K values of 0.158 and 0.229 L mg(-1) were obtained for amoxicillin trihydrate using activated carbon and micelle-clay complex, respectively. Filtration of antibacterials in the ppm range, which yielded variable degrees of removal depending on the volumes passed and flow rates, was simulated and capacities for the ppb range were estimated. Stability study in pure water and wastewater revealed that amoxicillin was totally stable for one month when kept at 37°C, whereas cefuroxime axetil underwent slow hydrolysis to cefuroxime.

[Study on the genotoxicity of cefuroxime lactone--an impurity substance in antibiotics].

OBJECTIVE: To study the genotoxicity of cefuroxime lactone, a kind of impurity in cefuroxime sodium, and to provide experimental basis for the toxicological safety evaluation of cefuroxime sodium. METHODS: A set of efficient and convenient genetic toxicity tests were used to evaluate the genotoxicity of cefuroxime lactone, focusing on gene mutation, chromosomal aberration, DNA damage and repair. RESULTS: (1) Ames assay: The number of colonies with back mutation (revertant) in varied strains of Salmonella typhimurium (TA97, 98, 100 and 102) through all doses of cefuroxime lactone did not exceed the number of spontaneous mutation colony by two times with or without rat liver microsomal enzymes (S9). (2) Micronucleus test in Kunming mice: Micronucleus rate in mice treated with 40 mg/kg cyclophosphamide, which used as a positive control, was 19.74 per thousand, significantly higher than that of negative control (1.82 per thousand) (P < 0.05), and micronucleus rate in mice dosed by 125, 250 and 500 (mg/kg) of cefuroxime lactone were 3.06 per thousand, 2.83 per thousand and 3.24 per thousand, showing no significant difference when compared with the negative control (P > 0.05). (3) Chromosome aberration assay: In the conditions of S9 existence or not, the chromosomal aberration rate of positive control (20 microg/ml cyclophosphamide and 0.1 microg/ml mitomycin c) was significantly higher than that of negative control (P < 0.05), while chromosomal aberration rate from cefuroxime lactone revealed no significant difference compared with the negative control (P > 0.05). (4) TK gene mutation assay: The relative survival (RS), relative viability (RV), relative suspension growth (RSG) and relative total growth (RTG) was decreased along with the increase of cefuroxime lactone concentrations, however, no significant difference was discovered between the dosed groups and negative control for TK gene mutation frequency (P > 0.05). (5) Comet assay: Comet rate of positive control (5.0 microg/ml methyl methanesulfonate) was 94.5%, higher than that of negative control (7.0%) (P < 0.05), while comet rates in varying concentrations of cefuroxime lactone showed no statistically difference compared with the negative control (P > 0.05). CONCLUSION: genotoxicity was observed under our experimental conditions, which suggested that cefuroxime lactone has no mutagenic effect.

Investigation of chromatographic conditions for the separation of cefuroxime axetil and its geometric isomer.

The optimal chromatographic conditions for the separation of the syn- and anti-geometric isomers of cefuroxime axetil applying RP-HPLC and micellar liquid chromatography (MLC) methods were investigated. The possibility to separate diastereoisomers of syn- and anti-cefuroxime axetil was observed. Investigations were performed using three columns, two classical silicas and one with hybrid particle technology. Three aqueous-organic and one micellar mobile phases were used. The best results were achieved using micellar mobile phase. Optimization study was performed using different micellar mobile phases. MLC method is sensitive and applicable in purity and stability testing.

Valoración in vitro de discos para antibiogramas de producción nacional / In vitro assessment of discs for antibiograms of national production

Se realizó la valoración in vitro de discos de antibióticos para antibiogramas producidos por primera vez en nuestro país. Estos correspondieron a ceftriaxoma, cefotaxima, cefazolina, cefuroxima, ceftazidima, ciprofloxacina, vancomicina y oxacillín. Dicha valoración comprendió la actividad in vitro de los discos, así como la determinación del grado de estabilidad de éstos. Fueron utilizadas 911 cepas bacterianas, incluidas bacterias gammnegativas y grampositivas, aisladas en pacientes del hospital. Se determinó que la ciprofloxacina fue el antibiótico más efectivo de todos. De forma global los antibióticos probados tuvieron muy buena actividad inhibitoria frente a bacterias grampositivas y en menor grado frente a gramnegativas. Se compararon los resultados obtenidos usando discos de producción nacional de 4 antibióticos y sus similares de producción extranjera. La ceftriaxona y la ceftaxioma nacionales alcanzaron mejores resultados, en oxacillín los resultados fueron idénticos en ambos y sólo en ciprofloxacina los discos nacionales tuvieron resultados ligeramente inferiores. Se comprobó que los discos probados mantuvieron su potencia a lo largo del estudio y no sufrieron alteraciones en su estado físico

Esters of cephalosporins. Part III. Separation and properties of the R and S isomers of the 1-acetoxyethyl ester of cefuroxime.

Two separation methods for the R and S isomers of the 1-acetoxyethyl ester of cefuroxime [I] were evaluated. Physico-chemical and biological properties of these isomers were studied. It was found that the R isomer after oral administration to rats is absorbed better and faster than the isomer S.