Trainor T M, Vouros P, Lampen P, Neumeyer J L, Baldessarini R J, Kula N S
Barnett Institute, Northeastern University, Boston, MA 02115.
J Chromatogr. 1988 Dec 21;457:257-66. doi: 10.1016/s0021-9673(01)82073-2.
A method for the determination of the neuroactive compound N-n-propylnorapomorphine (NPA) in biological tissues is described. Isolation of NPA from serum or brain tissue was achieved via liquid-liquid extraction from phosphate-buffered tissue extract (0.25 M, pH 7.2) into ethyl acetate. The NPA, along with a [2H7]NPA analogue serving as internal standard, was converted to the corresponding bis(trifluoroacetyl) ester by treatment with excess trifluoroacetic anhydride at 75 degrees C. The electrophoric derivatives were analyzed by fused-silica capillary gas chromatography-mass spectrometry in the negative ion chemical ionization mode. Selected ion monitoring of the [M-CF3CO]- ions of derivatized NPA (m/z 390) and internal standard [2H7]NPA (m/z 397) permitted the quantitation of NPA in serum and brain samples obtained from rats treated with either free NPA or the prodrug methylenedioxy-NPA (MDO-NPA). Calibration was conducted down to a practical limit of assay sensitivity, at 0.50 ng NPA per ml of serum and 0.50 ng NPA per g of brain. The relative standard deviation for replicate serum samples spiked at 20 ng/ml was 4.2% (n = 5) and for brain samples at 10 ng/g, it was 3.6%. This method revealed differences in the free NPA brain/serum ratios in rats treated separately with the stereoisomers R-(-)-MDO-NPA and S-(+)-MDO-NPA.
描述了一种测定生物组织中神经活性化合物N-正丙基去甲阿扑吗啡（NPA）的方法。通过将磷酸盐缓冲组织提取物（0.25M，pH 7.2）中的NPA液-液萃取至乙酸乙酯中，从血清或脑组织中分离出NPA。NPA与用作内标的[2H7]NPA类似物一起，在75℃下用过量的三氟乙酸酐处理，转化为相应的双（三氟乙酰）酯。通过熔融石英毛细管气相色谱-质谱在负离子化学电离模式下分析电泳衍生物。对衍生化NPA（m/z 390）和内标[2H7]NPA（m/z 397）的[M-CF3CO]-离子进行选择离子监测，可对用游离NPA或前药亚甲二氧基-NPA（MDO-NPA）处理的大鼠的血清和脑样品中的NPA进行定量。校准进行到实际检测灵敏度极限，血清中为每毫升0.50 ng NPA，脑中为每克0.50 ng NPA。加标浓度为20 ng/ml的重复血清样品的相对标准偏差为4.2%（n = 5），加标浓度为10 ng/g的脑样品的相对标准偏差为3.6%。该方法揭示了分别用立体异构体R-（-）-MDO-NPA和S-（+）-MDO-NPA处理的大鼠中游离NPA脑/血清比率的差异。
