A Study on Acetylglutamine Pharmacokinetics in Rat Blood and Brain Based on Liquid Chromatography-Tandem Mass Spectrometry and Microdialysis Technique

Abstract

Acetylglutamine (NAG) is the derivative of glutamine, which is the richest free amino acid in the human body. In this work, a novel reliable method of the combination of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and microdialysis (MD) technique for the evaluation of NAG and its metabolites g-aminobutyric acid (GABA) and glutamic acid (Glu) in rat blood and brain was proposed. A Zorbax SB-C 18 column (2.1 × 100 mm, 3.5 mM) was applied to separate the analytes. The mobile phase was acetonitrile-water (70:30, v/v) containing 5 mM ammonium acetate and the flow rate was 0.3 ml/min. Based on the multiple reaction monitoring (MRM) mode of positive ion, the precursors of product ions chosen for NAG, Glu, GABA, and Ncarbamyl-L-glutamic (NCG, IS) were (m/z) 189.1!130.0, 148.0!84.1, 104!87.1, and 191.0!130.1, respectively. All the validation data, including precision, accuracy, inter-day repeatability, matrix effect, and stability, were within the acceptable ranges according to the reference of Bioanalytical Method Validation Guidance for Industry (2018). Rats with microdialysis probes inserted into jugular vein and hippocampus were administered the low (75 mg/kg, NAG-L), medium (150 mg/kg, NAG-M), and high (300 mg/kg, NAG-H) doses of NAG and 10 ml/kg Guhong injection (GHI) by tail vein, respectively. In the blood test, the C max values of NAG-L group were markedly lower (P < 0.01) than those of NAG-M, NAG-H, and GHI groups, respectively. No differences were observed between NAG-M and GHI groups, while the C max values in GHI group were significantly upgraded compared with NAG-H group. There were notable differences in the C max values of NAG in brain dialysate after administration of NAG and GHI. The drug distribution coefficients of NAG, Glu, GABA in brain and blood at low, medium, high doses of NAG and GHI groups were 13.

Guhong Injection Alleviates Cerebral Ischemia–Reperfusion Injury via the PKC/HIF-1α Pathway in Rats

“…GHI, a formulation made by combining traditional Chinese and Western medicine components, is used for treating cerebral ischemia and coronary microvascular disease ( Ai et al, 2017 ; Jieqin et al, 2020 ). We have previously studied the pharmacokinetics of the active components of GHI was investigated in rat blood and brain ( Yu et al, 2018 ; Xu et al, 2020 ). Pharmacological studies have shown that GHI protects against cerebral I/R injury through anti-inflammatory and antithrombotic effects ( Shu et al, 2014 ; Ai et al, 2017 ).…”

“…GHI has been extensively applied in cerebrovascular disease treatment, mainly because of its anti-inflammatory and antioxidative effects (Ai et al, 2017;Shu et al, 2014;Zhou et al, 2021). Acetylglutamine (Figure 1A) is an acetyl derivative of glutamine-one of the most abundant free amino acids in humans (Xu et al, 2020). Aceglutamide can attenuate cerebral ischemia-reperfusion (I/R) injury (Zhang et al, 2020).…”

Unraveling the mystery of efficacy in Chinese medicine formula: New approaches and technologies for research on pharmacodynamic substances

“…(i) For endogenous metabolic markers, Wang’s team ( Wang et al, 2020a ) depending on microdialysis combined UPLC-QqQ-MS for relevant active compounds and endogenous neuroactive substances, which helped in substance basis and mechanism of TCM. Similarly, microdialysis plays a key role in elucidating disease mechanisms ( Xu et al, 2019 , Xu et al, 2020 , Mever et al, 2020 ; Su et al 2019). (ii) For in vivo single drug studies, microdialysis being applied for PK monitoring and quantification of drugs in skin tissue ( Voelkner et al 2018 ) and plasma ( Girondi et al, 2018 , Wang et al, 2020c ), among others.…”

Acetylglutamine facilitates motor recovery after brachial plexus root avulsion in ratsby promoting motoneuronal survival and axonal remyelination

“…Moreover, Glu is an excitatory neurotransmitter tightly associated with the plasticity of neurons, playing a vital role in the growth of neurons and the generation of synapses [13]. Accumulated evidence has con rmed that NAG can exert a neuroprotective effect following cerebral ischemia-reperfusion injury via neuronal apoptosis and in ammation attenuation [12]. NAG has been reported to cross the blood-brain barrier (BBB) and exert multiple bene cial effects on neurological diseases [11].…”

“…Acetylglutamine (N-acetyl-L-glutamine, NAG), the derivative of glutamine and generated by the acetylation of glutamine [10], can produce two metabolites, including g-aminobutyric acid (GABA) and glutamic acid (Glu) [11]. GABA can promote acetylcholine activity and maintain normal brain function [12]. Moreover, Glu is an excitatory neurotransmitter tightly associated with the plasticity of neurons, playing a vital role in the growth of neurons and the generation of synapses [13].…”