Optimization, validation and application of an assay for the activity of HMG-CoA reductase by LC-MS/MS.

A stable HMG-CoA reductase (HMGR) reaction was developed by a sensitive, selective and precise liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. The optimized enzyme reaction condition contained 1.5 μg of HMGR, 20 nM of NADPH with 50 min of reaction time.

Ultra-high-performance liquid chromatography for the determination of exenatide in monkey plasma by tandem quadrupole mass spectrometry.

A highly sensitive ultra-high-performance liquid chromatographic-tandem mass spectrometry (UPLC/MS/MS) method was developed for the quantification of the synthetic peptide drug of exenatide in monkey plasma. Sample preparation was carried out by solid-phase extraction (SPE), and bivalirudin was used as the internal standard (IS). An excellent chromatographic separation was obtained on a reversed-phase C column with a gradient elution.

Pharmacokinetics and bioavailability of cimicifugosides after oral administration of Cimicifuga foetida L. extract to rats.

Ethnopharmacological Relevance: Cimicifuga foetida L., a traditional Chinese medicine, has been used as an anti-inflammatory, antipyretic and analgesic remedy. The primary active constituents are believed to be present in the triterpene glycoside fraction.