Improved reversed phase liquid chromatographic method with pulsed electrochemical detection for tobramycin in bulk and pharmaceutical formulation

Tobramycin is one of the aminoglycoside antibiotics that lack a UV absorbing chromophore. However, the application of pulsed electrochemical detection （PED） has been used successfully for the analysis of this and similar antibiotics. This work describes an improved liquid chromatographic （LC） method combined with PED, which is able to separate much more impurities than before. Using a Discovery C-18 RP column （250 mm × 4.6 mm i.d., 5 μm）, isocratic elution was carried out with a mobile phase, containing sodium sulfate （35 g/L）, sodium octanesulphonic acid （1 g/L）, tetrahydrofuran （14mL/L） and 0.2 M phosphate buffer pH 3.0 （50 mL/L）. Using these experimental conditions, the limit of quantification （LOQ, S/N= 10） was 5 ng. The linearity was examined in the range LOQ-60 μg/mL and the coefficient of determination was 0.998. The method also proved to be repeatable and the recovery was close to 100%. The influence of the different chromatographic parameters on the separation was investigated by means of an experimental design. The proposed method is useful in quality control of tobramycin drug substances and drug products.

短期摄入硝酸盐膳食补充剂对健康人血液中基质金属蛋白酶9的影响（英文）

目的:研究硝酸盐膳食补充剂对血液中基质金属蛋白酶9的作用。方法:受试者血液中亚硝酸盐和硝酸盐的含量采用毛细管电泳紫外法检测。相应血液中基质金属蛋白酶9的含量采用酶联免疫荧光法和毛细管电泳质谱法检测。结果:研究表明,相比服用安慰剂,受试者在服用甜菜饮料后血液中的硝酸盐和亚硝酸盐分别显示3.5倍和40%增长。酶联免疫荧光法和毛细管电泳质谱法均线性良好,血液中基质金属蛋白酶9的定量限为0.25 ng·m L^(-1)。其中在8个受试者中,有4个受试者显示增长的硝酸盐/亚硝酸盐对血液中基质金属蛋白酶9有抑制作用。结论:结果显示短期服用硝酸盐膳食补充剂和血液中基质金属蛋白酶9降低有关。

高效液相色谱法测定生物样品中3PO的方法建立与验证（英文）

目的:建立并验证用于大鼠血清、脑脊液、大脑和脊髓中3-(3-吡啶)-1-(4-吡啶)-2-丙烯-1-酮(3PO)含量测定的HPLC-UV法。方法:样品处理使用蛋白沉淀的方法;色谱条件:色谱柱为Chromolith RP-18e(100 mm×4.6 mm),流动相A为乙腈-水(2.5∶97.5,v/v)添加0.1%TFA,流动相B为乙腈添加0.1%TFA,梯度洗脱[0～2.3 min,0%B→100%B(线性梯度);2.3～2.6 min,100%B(等度);2.6～2.7 min,100%B→0%B(线性梯度);2.7～5 min,0%B(等度)],流速2 mL·min-1,检测波长304 nm,进样量10μL。结果:大鼠的血清、脑脊液、大脑和脊髓中内源性物质不干扰3PO的测定,在上述4种基质中,该方法的检测限分别为0.2、0.1、0.1、0.1μg·mL-1;定量限分别为0.8、0.2、0.5、0.5μg·mL-1;线性范围分别为3～150、0.3～150、0.9～150、0.6～150μg·mL-1,相关系数均大于0.999;高、低浓度的回收率均在79.9%～100.3%的范围内;方法重复性(n=5)的RSD均大于0.9%。结论:建立的方法简单,线性范围宽,且选择性、耐用性均佳。