ADME & Tox. Research Institute, Sekisui Medical Company, Ltd., Tokai, Ibaraki 319-1182, Japan.
J Pharm Sci. 2011 Sep;100(9):4024-36. doi: 10.1002/jps.22646. Epub 2011 Jun 2.
Liquid chromatography-radioisotope-mass spectrometry (LC-RI-MS) analysis was used to determine the structures of 12 (four previously unknown) (14) C-tolbutamide (TB) metabolites in rat biological samples (plasma, urine, bile, feces, and microsomes). The four novel metabolites are ω-carboxy TB, hydroxyl TB (HTB)-O-glucuronide, TB-ortho or meta-glutathion, and tolylsulphoaminocarbo-glutathion. In rat plasma, after oral administration of (14) C-TB at therapeutic dose (1 mg/kg) and microdose (1.67 µg/kg), the total RI and six metabolites [HTB, carboxy TB (CTB), M1: desbutyl TB, M2: ω-hydroxyl TB, M3: α-hydroxyl TB, and M4: ω-1-hydroxyl TB] were quantified by LC-RI-MS. The plasma concentrations were calculated using their response factors (MS-RI intensity ratio) without standard samples, and the area under the curve (AUC) of plasma concentration per time for evaluation of Safety Testing of Drug Metabolites (MIST) was calculated using the ratio of TB metabolites AUC/total RI AUC. The ratios were as follows: TB 94.5% and HTB 2.5% for the microdose (1.67 µg/kg) and TB 95.6%, HTB 0.96%, CTB 0.065%, M1 0.62%, M2 0.0035%, M3 0.077%, and M4 0.015% for the therapeutic dose (1 mg/kg). These values were less than 10% of the MIST criteria.
采用液相色谱-放射性同位素-质谱（LC-RI-MS）分析方法，鉴定了大鼠生物样品（血浆、尿液、胆汁、粪便和微粒体）中 12 种（其中 4 种为新发现）（14）C-甲苯磺丁脲（TB）代谢物的结构。这 4 种新的代谢物为ω-羧酸 TB、羟基 TB（HTB）-O-葡糖苷酸、TB-邻位或间位谷胱甘肽以及甲苯磺氨甲酰基-谷胱甘肽。在大鼠血浆中，口服（14）C-TB 治疗剂量（1 mg/kg）和微剂量（1.67 µg/kg）后，通过 LC-RI-MS 定量分析了总 RI 和 6 种代谢物[HTB、羧基 TB（CTB）、M1：脱丁基 TB、M2：ω-羟基 TB、M3：α-羟基 TB 和 M4：ω-1-羟基 TB]。采用 LC-RI-MS 分析，未用标准样品，通过代谢物 RI 强度比值（MS-RI 强度比）计算血浆浓度，采用 TB 代谢物 AUC/总 RI AUC 的比值计算药物代谢物安全性测试（MIST）的 AUC 曲线下面积（AUC）。比值如下：微剂量（1.67 µg/kg）时 TB 为 94.5%，HTB 为 2.5%；治疗剂量（1 mg/kg）时 TB 为 95.6%，HTB 为 0.96%，CTB 为 0.065%，M1 为 0.62%，M2 为 0.0035%，M3 为 0.077%，M4 为 0.015%。这些值均低于 MIST 标准的 10%。
