Doxycyclin analysis

A. Van Schepdael, R. Kibaya, E. Roets, and J. Hoogmartnes, Analysis of doxycycline by capillary electrophoresis, Chromato- graphia, 41 361 (1995). 

A lead compound bearing a ferrocenyl moiety at position N(l) was identified. This derivative is more active than Ciprofloxacin and Doxycycline. The activity is remarkably constant regardless of the level of resistance to CQ of the strains. Contrary to other antibiotics, no delayed-death effect was noted. Isobologram analysis showed that this compound exerts an antagonist effect with the main quinoline-containing antimalarials. In vitro results have to be confirmed in vivo to check the bioavailability of the molecule and its potential interest as a new antimalarial [113],... 

Doxycycline inhibits the detachment of SM-exposed HaCaT cells in culture from the growth substrate. However, analysis of the metabolic activity of the adherent cells reveals that doxycycline treatment does not maintain cell viability. It is suggested that doxycycline and other matrix metalloprotease inhibitors may have a role to play in therapeutic intervention against SM, only as a combination therapy (Lindsay et al, 2007). Human keratinocyte cell lines were pretreated with mixtures of methenamine and glutathione prior to SM exposure. Though it is possible to protect the cell cultures from the toxic effects of SM, it will be effective only as a pretreatment (Smith et al, 1997). 

Cherlet et al. [44] reported the determination of TC, chlor-TC, oxy-TC, and doxycycline and their 4-epimers, in edible pig tissue. The compounds are extracted with a sodium succinate solution. After protein precipitation with trifluoroacetic acid (TEA) and paper filtration, the extract was purified on an Oasis HLB SPE cartridge, prior to LC-ESI-MS analysis. The limit of quantification (LOQ) was 50 pg/kg, which is 50% of the MRL in the EU. A similar method was applied by Andersen et al. [45] for the analysis in shrimp and whole milk. 

Several studies have employed chemometric designs in CZE method development. In most cases, central composite designs were selected with background electrolyte pH and concentration as well as buffer additives such as methanol as experimental factors and separation selectivity or peak resolution of one or more critical analyte pairs as responses. For example, method development and optimization employing a three-factor central composite design was performed for the analysis of related compounds of the tetracychne antibiotics doxycycline (17) and metacychne (18). The separation selectivity between three critical pairs of analytes were selected as responses in the case of doxycycline while four critical pairs served as responses in the case of metacychne. In both studies, the data were htted to a partial least square (PLS) model. The factors buffer pH and methanol concentration proved to affect the separation selectivity of the respective critical pairs differently so that the overall optimized methods represented a compromise for each individual response. Both methods were subsequently validated and applied to commercial samples. 

Magid, D., Douglas, Jr., J. M., and Schwartz, J. S. (1996). Doxycycline compared with azithromycin for treating women with genital Chlamydia trachomatis infections An incremental cost-effectiveness analysis. Ann. Intern. Med. 124, 389-399. 

Bocker, R. Rapid analysis of doxycycline from biological samples by high-performance liquid chromatography. J.Chromatogr., 1980, 187, 439-441 [whole blood serum tissue mouse liver]... 

Among the multi-class methods reported in the literature, a procedure that involves sample dissolution with EDTA under mildly acidic conditions (pH 4.0) followed by SPE with Oasis HLB cartridges has been applied for the simultaneous analysis of macroiides, tetracyclines, quinolones, and sulfonamides in honey samples Separation and determination by UPLC-MS/MS enabled the analysis of 17 compounds in <5 min. Mean recoveries ranged from 70% to 120%, except for three compounds (doxycycline, erythromycin, and tilmicosin), which had recoveries of >50%. Application of the method to the analysis of honey samples obtained from different beekeepers and local supermarkets... 

A meta-analysis of 6 studies involving 544 patients with brueellosis found a significantly higher numbers of relapses and lower numbers of initial cures if doxycycline was given with rifampicin rather than streptomycin. ... 

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