Dengtaiye tablet has been used to treat chronic bronchitis cough. Scholarisine, 19-epischolarisine, vallesamine, and picrinine are the representative constituents of Dengtaiye. A rapid and sensitive assay based on supercritical fluid chromatography with tandem mass spectrometry has been developed and validated for the determination of the diastereoisomers of scholarisine and 19-epischolarisine, vallesamine, and picrinine in rat plasma using lamotrigine as internal standard. The analysis in a run time of only 6 min was performed on an ACQUITY UPC² Trefoil^TM BEH 2-EP column (3.0 × 150 mm, 2.5 μm) at 50ºC. The mobile phase consisting of carbon dioxide and methanol (2 mM ammonium formate) was performed as follows: 15% methanol (2 mM ammonium formate) maintained at 0–2 min, 15–19% methanol (2 mM ammonium formate) at 2–4 min, 19–15% methanol (2 mM ammonium formate) at 4–6 min. The flow rate was 1.50 mL/min. The assay was linear over the concentration ranges 50–10000 pg/mL for scholarisine, 19-epischolarisine, vallesamine, and picrinine with corresponding lower limits of quantitation of 50 pg/mL. Intra- and interday precisions were in the range 1.42–12.85% with accuracies in the range –11.71–2.48%. The method was successfully applied to a pharmacokinetic study involving a single oral administration of 108 mg/kg Dengtaiye tablet to rats.

Lobaplatin, consisting of two diastereoisomers, is a third-generation platinum antineoplastic agent that has shown encouraging anticancer activity in a variety of tumor types. To investigate any stereospecificity in the pharmacokinetics of lobaplatin, a novel, simple, rapid and sensitive supercritical fluid chromatography with tandem mass spectrometry method was developed for the simultaneous quantitation of lobaplatin diastereoisomers in rat plasma. After a simple protein precipitation with methanol, the analytes and dexpantoprazole (internal standard) were chromatographed on an Acquity UPC² system with a Chiralcel OZ-RH column using a mobile phase consisting of carbon dioxide and methanol (65:35, v/v) at 40°C over 6 min. The assay was linear over a concentration range of 25–15 000 ng/mL for both diastereoisomers using 100 μL of rat plasma for sample preparation. The lower limit of quantification was 25 ng/mL for both compounds, which was sufficient to detect the diastereoisomers in the incurred samples within this study. Intra- and inter-day precisions were below 11.8% and the accuracies were below 4.5%. The validated method was successfully applied to a pharmacokinetic study after an intravenous administration of 7.6 mg/kg lobaplatin to rats. There was no apparent stereospecificity in the pharmacokinetics between the two diastereoisomers of lobaplatin.