Pharmacokinetics and mass balance of vericiguat in rats and dogs and distribution in rats

Determination of vericiguat in rat plasma by UPLC-MS/MS and its application to drug interaction

Vericiguat (VER) is a novel soluble guanylate cyclase stimulator treating symptomatic chronic heart failure (HF), and it is a substrate of both transporters P-glycoprotein and breast cancer resistance protein (BCRP). Astragaloside IV (ASIV) is the main active ingredient in Radix Astragali (Huangqi), a traditional Chinese medicine widely used for HF treatment in China. ASIV's effect on the protein expression of P-glycoprotein and BCRP has been observed, its impact on VER metabolism remain uncertain. In the present study, male Sprague-Dawley rats were administered with 20 mg/kg ASIV and 1 mg/kg VER to study their pharmacokinetics. Blood samples were subject to liquid-liquid extraction, and riociguat was employed as the internal standard (IS). The analytical method involved a C18 column (XSelect® HSS T3 column, 2.1 × 100 mm, 2.5 μm) with a mobile phase of 0.1% formic acid and acetonitrile for gradient elution. The flow rate of the mobile phase was set at 0.2 mL/min, and 5 µL of the sample was used for analysis. The positive ion multi-response monitoring mode was utilized with a transition of m/z 427.4→109.1 for VER and m/z 423.3→109.1 for the IS. The method exhibited good linearity within the concentration range of 0.1 to 300 ng/mL (r = 0.9987), and all the validation processes were conducted in accordance with the requirements of biological analysis. The pharmacokinetic results revealed that ASIV did not significantly alter the main parameters of VER, except for Cmax, which decreased by 33.2% (P < 0.05). Overall, our study successfully established a selective, sensitive and repeatable ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis for detecting VER in rat plasma.

Study and exploration of the pharmacokinetics of traditional Tibetan medicine Ruyi Zhenbao tablets after single and long-term administration

Tibetan medicine is one of the oldest traditional medicine systems in the world. Taking the Ruyi Zhenbao tablet (RYZB) as an example, which is a widely used classic oral Tibetan medicine, this article discusses the pharmacokinetics of single administration and long-term treatment and analyzed its metabolic properties and tissue distribution in vivo. After single administration, blood samples were collected before administration and at different time points after administration in different groups of rats. In the study of long-term treatment effects, blood samples were collected from the animals in each group on days 1, 15, and 30 and on day 15 after withdrawal. The results showed that after a single administration, the dose change had no significant effect on the T_1/2 and T_max of agarotetrol, isoliquiritigenin, and piperine (p > 0.05). There was a certain correlation between the increase in AUC_0-t and the C_max of agarotetrol, isoliquiritigenin, piperine, and the increase in dosage, with a dose range of 0.225–0.900 g/kg. There were no significant differences in C_max and AUC_0-t of ferulic acid at different doses (p > 0.05). Meanwhile, there was no significant sex-based difference in the pharmacokinetic parameters of these four components in rats. After long-term administration, the distribution agarotetrol in various tissues of rats was kidney > liver > heart > brain; the tissue distribution in low- and medium-dose groups of isoliquiritigenin was liver > kidney > heart > brain, and in the high-dose group, kidney > liver > heart > brain. The tissue distribution of piperine in each dose group was liver > kidney > heart > brain, and that of ferulic acid in each dose group was kidney > liver > heart > brain. Through the establishment of the previously developed methodology, the pharmacokinetic properties of RYZB were analyzed after a single administration and long-term administration. Our findings confirmed this approach for the exploration and establishment of a pharmacokinetic evaluation of Tibetan medicine, to support its guiding role in clinical application, but also to accelerate research into Tibetan medicine theory and medicine and to provide a solid foundation for the translation of Tibetan medicine throughout the world.