Department of Pathophysiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan.
J Mass Spectrom. 2011 May;46(5):502-7. doi: 10.1002/jms.1917.
D-Serine is a co-agonist of the N-methyl-D-aspartate receptor in glutamate neurotransmission and has been proposed as a potential therapeutic agent for schizophrenia. However, D-serine also acts as a nephrotoxic substance in rats at high doses. To investigate the pharmacokinetics and toxicokinetics of D-serine, a method for the stereoselective determination of serine enantiomers in rat plasma was developed using GC-MS with selected ion monitoring (GC-MS-SIM). DL-[(2)H(3)]Serine was used as an internal standard to account for losses associated with the extraction, derivatization and chromatography. Serine enantiomers were purified by cation-exchange chromatography using BondElut SCX cartridge and derivatized with HCl in methanol to form methyl ester followed by subsequent N,O-diacylation with optically active (+)-α-methoxy-α-trifluoromethylphenylacetyl chloride to form epimeric amide. Quantitation was performed by SIM of the molecular-related ions of the epimers in the chemical ionization mode. The intra- and inter-day reproducibility of the assay was less than 5% for D-serine and 3% for L-serine. The method was successively applied to study the pharmacokinetics of D-serine in rats.
D-丝氨酸是谷氨酸能神经传递中 N-甲基-D-天冬氨酸受体的协同激动剂，被提议作为精神分裂症的潜在治疗药物。然而，D-丝氨酸在高剂量下也会在大鼠中充当肾毒性物质。为了研究 D-丝氨酸的药代动力学和毒代动力学，开发了一种使用气相色谱-质谱联用（GC-MS）与选择离子监测（GC-MS-SIM）对大鼠血浆中丝氨酸对映体进行立体选择性测定的方法。使用 DL-[(2)H(3)]丝氨酸作为内标，以弥补与提取、衍生化和色谱相关的损失。丝氨酸对映体通过阳离子交换色谱使用 BondElut SCX 小柱进行纯化，并在甲醇中与 HCl 衍生化，形成甲酯，然后用光学活性（+）-α-甲氧基-α-三氟甲基苯乙酰氯进行后续 N,O-二酰化，形成差向异构体酰胺。通过化学电离模式下差向异构体的分子相关离子的 SIM 进行定量。该测定方法的日内和日间重现性对于 D-丝氨酸小于 5%，对于 L-丝氨酸小于 3%。该方法成功地应用于研究大鼠中 D-丝氨酸的药代动力学。
