In the present study,roxithromycin solutions of different pH values were prepared with water,simulated gastric fluid(SGF)and simulated intestinal fluid(SIF).Stability of roxithromycin in theabove solutions were determ...In the present study,roxithromycin solutions of different pH values were prepared with water,simulated gastric fluid(SGF)and simulated intestinal fluid(SIF).Stability of roxithromycin in theabove solutions were determined separately by colorimetry,TLC and HPLC.All the three methods achievedan identical conclusion that this drug was stable in water and SIF.However,for the stability test ofroxithromycin in SGF,the results obtained by colorimetry were contrary to those by TLC and HPLC.According to the results by colorimetry,this drug was stable in SGF for as long as 168 hours.However,whentested by TLC and HPLC,decomposition of this drug was found within 2 h and 10 min separately.Accordingto the determination by HPLC,8.15%and 62.02%of roxithromycin were decomposed in 10 min and 2 h inSGF.which can be explained like this:the decomposition products reacted with H_SO,to form a solutionwith the same photo-absorptivity range as that of the original drug.Accordingly,colorimetry is not suitablefor the assay and stability test of roxithromycin in acidic solution like SGF.Similarly,we also have reason topredict that microbacterial assay is not suitable for roxithromycin in acidic solution if the decompositionproduct still has antibacterial activities.展开更多
A new method of determination for roxithromycin tablets by non-aqueous capillary electrophoresis (NACE) with square-wave amperometric detection was carried out. Several parameters affecting the NACE-AD determination ...A new method of determination for roxithromycin tablets by non-aqueous capillary electrophoresis (NACE) with square-wave amperometric detection was carried out. Several parameters affecting the NACE-AD determination were studied. The data was modified by spline wavelet least square (SWLS). The method is simple, rapid and highly reliable for routine analysis.展开更多
Roxithromycin, livestock growth promoter, as widely used medicine and arouses concern because its occurrence and persistence in soil environments. However, effects of roxithromycin in higher plants are still vague. Ac...Roxithromycin, livestock growth promoter, as widely used medicine and arouses concern because its occurrence and persistence in soil environments. However, effects of roxithromycin in higher plants are still vague. Accordingly, we hypothesized that roxithromycin-con- taminated soil may exhibits ecotoxicological effects in wheat （Triticum aestivum）. In this study, effects induced by a gradient concentration of roxithromycin stress （0.01, 0.1, 1, 10, and 100 mg.kg-1） was investigated in a 7-d soil test in T. aestivum. Results indicated that the specific activity of cytochrome P450 （CYP450） monooxygenase was decreased dramatically with the concentration of roxithro- mycin in soil. The IC50 value was 8.78mg.kg-1 of roxithromycin. On the contrary, the growth related endpoints （i.e., the germination percentage, the biomass and the height）, the content related endpoints （i.e., soluble protein content and CYP450 content）, and the superoxide dismutase （SOD） activity failed to reveal the roxithromy- cin-induced effects. Further analysis revealed that the CYP450 monooxygenase specific activity reduction was enzymatic mechanism mediated, other than oxidative stress induced. We conclude that the soil roxithromycin declined the CYP450 monooxygenase activity in T. aestivum by the inhibition of the enzymatic mechanism. Further efforts can include, but are not limited to, investigation of joint effects induced by combined exposure of roxithromycin and the pesticides and evalua- tion of the similar effects in other higher plants.展开更多
文摘In the present study,roxithromycin solutions of different pH values were prepared with water,simulated gastric fluid(SGF)and simulated intestinal fluid(SIF).Stability of roxithromycin in theabove solutions were determined separately by colorimetry,TLC and HPLC.All the three methods achievedan identical conclusion that this drug was stable in water and SIF.However,for the stability test ofroxithromycin in SGF,the results obtained by colorimetry were contrary to those by TLC and HPLC.According to the results by colorimetry,this drug was stable in SGF for as long as 168 hours.However,whentested by TLC and HPLC,decomposition of this drug was found within 2 h and 10 min separately.Accordingto the determination by HPLC,8.15%and 62.02%of roxithromycin were decomposed in 10 min and 2 h inSGF.which can be explained like this:the decomposition products reacted with H_SO,to form a solutionwith the same photo-absorptivity range as that of the original drug.Accordingly,colorimetry is not suitablefor the assay and stability test of roxithromycin in acidic solution like SGF.Similarly,we also have reason topredict that microbacterial assay is not suitable for roxithromycin in acidic solution if the decompositionproduct still has antibacterial activities.
基金This work was supported by the National Natural Science Foundation of China and Guang Dong Provincial Natural Science Foundation(29675033 and 20175037 001237)
文摘A new method of determination for roxithromycin tablets by non-aqueous capillary electrophoresis (NACE) with square-wave amperometric detection was carried out. Several parameters affecting the NACE-AD determination were studied. The data was modified by spline wavelet least square (SWLS). The method is simple, rapid and highly reliable for routine analysis.
基金This research is financially supported by the National Natural Science Foundation of China as a general project （Grant No. 31170473） and a joint Guangdong project （No. U1133006）, and by the Ministry of Education of China as an innovative team project （No. IRT 13024）.
文摘Roxithromycin, livestock growth promoter, as widely used medicine and arouses concern because its occurrence and persistence in soil environments. However, effects of roxithromycin in higher plants are still vague. Accordingly, we hypothesized that roxithromycin-con- taminated soil may exhibits ecotoxicological effects in wheat （Triticum aestivum）. In this study, effects induced by a gradient concentration of roxithromycin stress （0.01, 0.1, 1, 10, and 100 mg.kg-1） was investigated in a 7-d soil test in T. aestivum. Results indicated that the specific activity of cytochrome P450 （CYP450） monooxygenase was decreased dramatically with the concentration of roxithro- mycin in soil. The IC50 value was 8.78mg.kg-1 of roxithromycin. On the contrary, the growth related endpoints （i.e., the germination percentage, the biomass and the height）, the content related endpoints （i.e., soluble protein content and CYP450 content）, and the superoxide dismutase （SOD） activity failed to reveal the roxithromy- cin-induced effects. Further analysis revealed that the CYP450 monooxygenase specific activity reduction was enzymatic mechanism mediated, other than oxidative stress induced. We conclude that the soil roxithromycin declined the CYP450 monooxygenase activity in T. aestivum by the inhibition of the enzymatic mechanism. Further efforts can include, but are not limited to, investigation of joint effects induced by combined exposure of roxithromycin and the pesticides and evalua- tion of the similar effects in other higher plants.
