为了测定银杏内酯B(ginkgolide B,GB)与不同种属血浆蛋白的结合率,采用平衡透析法平衡72h,取透析袋内外两侧的液体加入内标物银杏内酯A,乙醚液液萃取后,用气相色谱-质谱联用仪测定GB浓度.GB在浓度为1、2、4 μg/mL时与大鼠血浆蛋白的结合率分别为(16.4 ± 5.3)% 、(16.9 ± 5.3)%和(21.3 ± 2.8)% ;与犬血浆蛋白的结合率分别为(14.8 ± 8.3)% 、(20.1 ± 6.3)%和(22.4 ± 5.0)% ;与健康人血浆蛋白的结合率分别为(19.3 ± 6.8)% 、(19.9 ± 2.9)%和(21.9 ± 7.1)%.在1-4μg/mL浓度范围内,GB血浆蛋白结合率在14.8%-22.4%,各种属蛋白结合率无明显剂量依赖性,各种属间无显著差异性.GB蛋白结合率较低,约80%以游离药物形式存在.
To determine the binding rate of ginkgolide B (GB) to plasma proteins of different species, by equilib-rium dialysis method for 72 h, the fluids of the internal and external dialysis bags were sampled and then the in-ternal standard ginkgolide A was added into these samples. After these samples were extracted with ether, the concentration of GB was determined by gas chromatography-mass spectrometry (GC-MS). The plasma protein binding rates of ginkgolide B with rat plasma in the dialysis bag at initial concentrations of 1, 2, and 4 μg/mL were (16.4 ± 5.3)%, (16.9 ± 5.3)% and (21.3 ± 2.8)%, respectively. The binding rates with canine plasma pro-teins were (14.8 ± 8.3)%, (20.1 ± 6.3)% and (22.4 ± 5.0)%, respectively. The binding rates with healthy human plasma were (19.3 ± 6.8)%, (19.9 ± 2.9)% and (21.9 ± 7.1)%, respectively. In the GB concentra-tion range of 1-4 μg/mL, the plasma protein binding rates to GB ranged from 14.8% to 22.4%, the protein binding rates of various genera were no notable dose-dependence and there were no significant differences among the various species. The binding rate was low, and about 80% GB was free.