Differentiation of volatile aromatic isomers and structural elucidation of volatile compounds in essential oils by combination of HPLC separation and crystalline sponge method.

Structure elucidation of volatile aromatic isomers at trace level has long been considered as an elusive task, due to their structural similarities and similar polarities, even with the aid of many spectroscopic techniques such as mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy. Single-crystal X-ray diffraction (SCD) is recognized as one of the most powerful structural elucidation techniques. The recently developed crystalline sponge method overcomes the intrinsic limitation of SCD that the target molecules must be single crystals, being able to analyze non-crystalline and trace-amount compounds without any special treatment.

[Study on UPLC Fingerprint of Corydalis bungeana].

Objective: To establish an Ultra Performance Liquid Chromatography fingerprint of Corydalis bungeana from different habitats.

Methods: UPLC-PDA was adopted to analysis ten batches of Corydalis bungeana from different habitats with Phenomenex Luna C₁₈ column (250 mm x 4.6 mm, 5 µm) eluted with the mobile phase of acetonitrile and 0.

Rapid, sensitive and selective HPLC-MS/MS method for the quantification of topically applied besifloxacin in rabbit plasma and ocular tissues: Application to a pharmacokinetic study.

Besifloxacin is a fourth-generation broad-spectrum fluoroquinolone registered for the topical treatment of bacterial conjunctivitis. In this study, a rapid, sensitive and selective liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for quantification of besifloxacin in rabbit plasma and ocular tissues using nateglinide as the internal standard (IS). The analyte and IS were separated on a Sepax GP-Phenyl column by isocratic elution with methanol-acetonitrile-5 mM ammonium formate-formic acid (29:55:16:0.

Development and validation of a high-performance liquid chromatography-tandem mass spectrometry method for the rapid simultaneous quantification of aconitine, mesaconitine, and hypaconitine in rat plasma after oral administration of Sini decoction.

A rapid, sensitive, and specific liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS-MS) method was developed and validated for simultaneous determination of aconitine (AC), mesaconitine (MA), and hypaconitine (HA), the three toxic constituents from Sini decoction (SND) in rat plasma. After the addition of citalopram as the internal standard (IS), plasma samples were basified with 100 microL 10% ammonium hydroxide, and then extracted with 1 mL ethyl acetate. Chromatographic separation was performed on a CN column (250 mm x 4.

Pharmacokinetic properties of S-adenosylmethionine after oral and intravenous administration of its tosylate disulfate salt: a multiple-dose, open-label, parallel-group study in healthy Chinese volunteers.

Background: S-adenosylmethionine (SAMe) is an endogenous molecule that plays an important role in cellular metabolism. Despite being widely used as a dietary supplement with claimed benefits for numerous conditions, there is little information about the pharmacokinetic properties of exogenous SAMe.

Objectives: One aim of this study was to characterize the pharmacokinetic properties of SAMe after administration of single and multiple doses of orally and intravenously administered SAMe tosylate disulfate (STD) in healthy male and female Chinese volunteers.

[Enantioseparation of amlodipine maleate by capillary electrophoresis using colominic acid as a chiral selector and the mechanism of chiral recognition].

Aim: Colominic acid, a novel chiral selector, was applied to enantioseparation of dihydropyridine derivative by capillary electrophoresis. A new method was developed for enantioseparation of amlodipine maleate, a novel calcium channel blocking therapeutic agent. The chiral recognition mechanism of colominic acid to amlodipine maleate was studied.