1. Absolute bioavailability, dose proportionality, and tissue distribution of rotundic acid in rats based on validated LC-QqQ-MS/MS method
- Author
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Min Wang, Haihua Shang, Duanyun Si, Xiaohan Dai, Mi Li, Yuan Gu, Changxiao Liu, Zerong Liu, Quansheng Li, and Yueyi Kai
- Subjects
Absorption (pharmacology) ,Chromatography ,biology ,Chemistry ,010401 analytical chemistry ,Selected reaction monitoring ,Pharmaceutical Science ,02 engineering and technology ,Pharmacy ,021001 nanoscience & nanotechnology ,biology.organism_classification ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,Bioavailability ,Ilex rotunda ,chemistry.chemical_compound ,Pharmacokinetics ,Oral administration ,Drug Discovery ,Electrochemistry ,Ammonium formate ,Protein precipitation ,0210 nano-technology ,Spectroscopy - Abstract
Rotundic acid (RA), an ursane-type pentacyclic triterpene acid isolated from the dried barks of Ilex rotunda Thunb. (Aquifoliaceae), possesses diverse bioactivities. To further study its pharmacokinetics, a simple and sensitive liquid chromatography with triple quadrupole mass spectrometry (LC-QqQ-MS/MS) method was developed and validated to quantify RA concentration in rat plasma and tissue using etofesalamide as an internal standard (IS). Plasma and tissue samples were subjected to one-step protein precipitation. Chromatographic separation was achieved on a ZORBAX Eclipse XDB-C18 column (4.6 mm × 50 mm, 5 μm) under gradient conditions with eluents of methanol:acetonitrile (1:1, V/V) and 5 mM ammonium formate:methanol (9:1, V/V) at 0.5 mL/min. Multiple reaction monitoring transitions were performed at m/z 487.30 → 437.30 for RA and m/z 256.10 → 227.10 for IS in the negative mode. The developed LC-QqQ-MS/MS method exhibited good linearity (2–500 ng/mL) and was fully validated in accordance with U.S. Food and Drug Administration bioanalytical guidelines. Dose proportionality and bioavailability in rats were determined by comparing pharmacokinetic data after single oral (10, 20, and 40 mg/kg) and intravenous (10 mg/kg) administration of RA. Tissue distribution was studied following oral administration at 20 mg/kg. The results showed that the absolute bioavailability of RA after administration at different doses ranged from 16.1% to 19.4%. RA was rapidly absorbed in a dose-dependent manner and highly distributed in the liver. In conclusion, this study is the first to systematically elucidate the absorption and distribution characteristics of RA in rats, which could provide additional information for further development and evaluation of RA in drug metabolism and pharmacokinetic studies.
- Published
- 2022