Diazo probe-based chemical isotope labeling assisted liquid chromatography-tandem mass spectrometry analysis for sensitive determination of amino acids in biofluids.

Amino acids are important biomolecules and contribute to essential biological processes. Liquid chromatography tandem mass spectrometry (LC-MS) now is a powerful tool for the analysis of amino acid metabolites; however, the structural similarity and polarity of amino acids can lead to the poor chromatographic retention and low detection sensitivities. In this study, we used a pair of light and heavy isotopomers of diazo probes, d/d-2-(diazomethyl)-N-methyl-N-phenyl-benzamide (2-DMBA/d -2-DMBA) to label amino acids.

A Comprehensive Study on the Chemical Constituents and Pharmacokinetics of Erzhi Formula and Jiawei Erzhi Formula Based on Targeted and Untargeted LC-MS Analysis.

Background: Erzhi formula (EZF) is a traditional Chinese medicine prescription, which has been widely used in the treatment of osteoporosis and premature ovarian failure.

Objective: To enhance curative effects, the other two herbal medicines, including Spatholobi Caulis (SC) and Achyranthes bidentata Blume (ABB), were added into the original EZF formula to obtain two new Jiawei-EZF (JW-EZF) preparations. To clarify the effect of the compatibility of herbs for original formulas, the chemical constituents and bioactive compounds in vivo were detected.

Comprehensive investigation on the metabolism of emodin both in vivo and in vitro.

Emodin is a natural anthraquinone, which displays numerous pharmacological activities, including anti-tumor, anti-inflammation and immunosuppression. However, there was no comprehensive study on its absorption, metabolism, distribution, and excretion. In order to further evaluation on the possibility of drug development of emodin, both in vivo and in vitro experiments were fulfilled in this study.

Studies on Chemical Characterization of Ginkgo Amillaria Oral Solution and Its Drug-Drug Interaction With Piceatannol 3'---D-Glucopyranoside for Injection.

Ginkgo Amillaria oral solution (GAO) is commonly used for the treatment of cardiovascular and cerebrovascular diseases in China. Piceatannol-3'---D-glucopyranoside for injection (PGI) is mainly used for the prevention and treatment of ischemic cerebrovascular diseases. With the spread of cerebrovascular disease, the possibility of combining the two drugs has increased; however, there is no research on the drug-drug interaction (DDI) between these two medicines.