Haglock Carrie, Wolf Carl, Poklis Alphonse
Department of Forensic Science, Virginia Commonwealth University, Richmond, Virginia, USA.
J Anal Toxicol. 2008 Oct;32(8):544-6. doi: 10.1093/jat/32.8.544.
Guanfacine (Tenex), an antihypertensive available since 1975, has recently been indicated for the treatment of attention deficit hyperactivity disorder in children (Intuniv). Because of this new usage, a gas chromatography-mass spectrometry method was developed and validated for the determination of guanfacine in urine. Guanfacine and 100 ng of protriptyline (internal standard) were extracted from 1.0 mL urine with 0.5 mL of saturated carbonate/bicarbonate buffer and 2 mL of ethyl acetate. The solvent extract was evaporated and derivatized with heptaflurobutyric anhydride in n-butyl chloride. Chromatographic separation was achieved using a DB-5 capillary column (30 m x 0.32 mm, 0.25 microm). Ions monitored for guanfacine were m/z 86.1, 272.1, and 274.1, and ions monitored for protriptyline were m/z 191.1 and 189.1. Concentrations were determined using calibrators over the range of 0.1-2.0 mg/L. The linear regression for all calibration curves had r2 values > or = 0.99. The limit of detection was 0.05 mg/L; limit of quantitation was 0.1 mg/L; and upper limit of linearity was 10.0 mg/L. Percent recovery of guanfacine at 0.1 and 2.0 mg/L was 93% and 71%, respectively. The method was found acceptable for routine quantitative analysis of guanfacine in urine.
胍法辛（商品名：Tenex）自1975年起作为抗高血压药物上市，最近已被批准用于治疗儿童注意力缺陷多动障碍（商品名：Intuniv）。由于这一新用途，开发并验证了一种气相色谱 - 质谱法用于测定尿液中的胍法辛。将胍法辛和100 ng丙咪嗪（内标）从1.0 mL尿液中用0.5 mL饱和碳酸盐/碳酸氢盐缓冲液和2 mL乙酸乙酯萃取。将溶剂提取物蒸发，并用七氟丁酸酐在正丁基氯中进行衍生化。使用DB - 5毛细管柱（30 m×0.32 mm，0.25μm）进行色谱分离。监测胍法辛的离子为m/z 86.1、272.1和274.1，监测丙咪嗪的离子为m/z 191.1和189.1。使用浓度范围为0.1 - 2.0 mg/L的校准品测定浓度。所有校准曲线的线性回归r2值≥0.99。检测限为0.05 mg/L；定量限为0.1 mg/L；线性上限为10.0 mg/L。胍法辛在0.1和2.0 mg/L时的回收率分别为93%和71%。该方法被认为可用于尿液中胍法辛的常规定量分析。
