Liquid chromatography–mass spectrometry method for determination of tetramethylpyrazine and its metabolite in dog plasma

• Published in: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Analytical technologies in the biomedical and life sciences, 2004-12, Vol.813 (1), p.263-268
• Main Authors: Wang, Peng, Jin, Xin, Qi, Meiling, Fang, Lin
• Format: Article
• Language: English
• Subjects: Analysis; Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Chromatography, Liquid - methods; Dog plasma; Dogs; Fundamental and applied biological sciences. Psychology; General pharmacology; Liquid chromatography–mass spectrometry; Medical sciences; Metabolite; Pharmacology. Drug treatments; Pyrazines - blood; Reproducibility of Results; Sensitivity and Specificity; Spectrometry, Mass, Electrospray Ionization - methods; Tetramethylpyrazine
• ISSN: 1570-0232; 1873-376X
• DOI: 10.1016/j.jchromb.2004.09.048

A liquid chromatography–mass spectrometry method is described for the determination of tetramethylpyrazine (TMP) and its active metabolite, 2-hydroxymethyl-3,5,6-trimethylpyrazine (HTMP) in dog plasma. This method involves a plasma clean-up step using protein precipitation procedure followed by LC separation and positive electrospray ionization mass spectrometry detection (ESI-MS). Chromatographic separation of the analytes was achieved on a C18 column using a mobile phase of methanol, water and acetic acid (50:50:0.6, v/v/v) at a flow rate of 1.0 ml/min. Selected ion monitoring (SIM) mode was used for analyte quantitation at m/ z 137.2 for TMP, m/ z 153.2 for HTMP and m/ z 195.2 for caffeine. The linearity was obtained over the concentration ranges of 20–6000 ng/ml for TMP and 20–4000 ng/ml for HTMP and the lower limit of quantitation was 20 ng/ml for both analytes. For each level of QC samples, both inter- and intra-day precisions (R.S.D.) were ≤7.4% for TMP and ≤6.0% for HTMP, and accuracy (R.E.) was ±6.0% for TMP and ≤3.5% for HTMP. The proposed LC–MS method was successfully applied to the pharmacokinetic studies of a TMP formulation preparation after oral administration to beagle dogs.