Pharmacokinetic Interaction Study of Ketamine and Rhynchophylline in Rat Plasma by Ultra-Performance Liquid Chromatography Tandem Mass Spectrometry

Pharmacokinetic interaction between rhynchopylline and pellodendrine via CYP450 enzymes and P-gp

CONTEXT

Rhynchopylline and pellodendrine are major extractions of commonly used Chinese medicine in gynaecology. The interaction between these two compounds could affect treatment efficiency and even result in toxicity during their co-administration in gynaecological prescription.

OBJECTIVE

The pharmacokinetic interaction between rhynchopylline and pellodendrine and the potential mechanism were investigated in this study.

MATERIALS AND METHODS

Sprague-Dawley rats were randomly divided into four groups to investigate the pharmacokinetic interaction between rhynchopylline (30 mg/kg) and pellodendrine (20 mg/kg) with single dose of these two drugs as the control. The transport of rhynchopylline was evaluated in the Caco-2 cell model. Additionally, the metabolic stability and the activity of corresponding CYP450 enzymes were assessed in rat liver microsomes.

RESULTS

The pharmacokinetic profile of rhynchopylline was dramatically affected by pellodendrine with the increased area under the pharmacokinetic curve (3080.14 ± 454.54 vs. 1728.08 ± 220.598 μg/L*h), C_max (395.1 ± 18.58 vs. 249.1 ± 16.20 μg/L), prolonged t_1/2 (9.74 ± 2.94 vs. 4.81 ± 0.42 h) and the reduced clearance rate (from 11.39 ± 1.37 to 5.67 ± 1.42 L/h/kg). No significant changes were observed in the pharmacokinetics of pellodendrine. The transport of rhynchopylline was significantly inhibited by pellodendrine with a decreasing efflux ratio (1.43 vs. 1.79). Pellodendrine significantly inhibited the activity of CYP1A2 and CYP2C9 with IC₅₀ values of 22.99 and 16.23 μM, which are critical enzymes responsible for the metabolism of rhynchopylline.

DISCUSSION AND CONCLUSIONS

The adverse interaction between rhynchopylline and pellodendrine draws attention to the co-administration of these two herbs and provides a reference for further investigations with a broader study population.

Uncaria rhynchophylla and its Major Constituents on Central Nervous System: A Review on Their Pharmacological Actions

BACKGROUND

Uncaria rhynchophylla (Miq.) Jacks (Rubinaceae), a common herbal medicine known as Gou-teng in Chinese, is commonly used in Chinese medicine practice for the treatment of convulsions, hypertension, epilepsy, eclampsia and other cerebral diseases. The major active components of U. rhynchophylla are alkaloids, terpenoids and flavonoids. The protective effects of U. rhynchophylla and its major components on central nervous system (CNS) have become a focus of research in recent decades.

OBJECTIVE

The study aimed to systematically summarize the pharmacological activities of U. rhynchophylla and its major components on the CNS.

METHODS

This review summarized the experimental findings from our laboratories, together with other literature data obtained through a comprehensive search of databases including the Pubmed and the Web of Science.

RESULTS

U. rhynchophylla and its major components such as rhynchophylline and isorhynchophylline have been shown to have neuroprotective effects on Alzheimer's disease, Parkinson's disease, depression, cerebral ischaemia through a number of mechanisms including anti-oxidant, anti-inflammatory actions and regulation on neurotransmitters.

CONCLUSION

U. rhynchophylla and its major components have multiple beneficial pharmacological effects on CNS. Further studies on U. rhynchophylla and its major components are warranted to fully illustrate the underlying molecular mechanisms, pharmacokinetics, and toxicological profiles of these naturally occurring compounds and their potential for clinical application.

Pharmacokinetic Effects of l-Tetrahydropalmatine on Ketamine in Rat Plasma by Ultraperformance Liquid Chromatography Tandem Mass Spectrometry

Male Sprague-Dawley rats (n = 18) were randomly divided into three groups: a saline group (20 mL/kg by gavage), a ketamine (KET) group (100 mg/kg by gavage), and a KET (the same routes and doses) combined with levo-tetrahydropalmatine (l-THP; 40 mg/kg by gavage) group (n = 6). Blood samples were acquired at different time points after drug administration. A simple and sensitive ultraperformance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was established to determine the concentrations of KET and its metabolite, norketamine (NK), in rat plasma. Chromatographic separation was achieved using a BEH C18 column (2.1 mm × 50 mm, 1.7 μm) with chlorpheniramine maleate (Chlor-Trimeton) as an internal standard (IS). The initial mobile phase consisted of acetonitrile–water with 0.1% methanoic acid (80 : 20, v/v). The multiple reaction monitoring (MRM) modes of m/z 238.1→m/z 179.1 for KET, m/z 224.1→m/z 207.1 for NK, and m/z 275→m/z 230 for Chlor-Trimeton (IS) were utilized to conduct a quantitative analysis. Calibration curves of KET and NK in rat plasma demonstrated good linearity in the range of 2.5–500 ng/mL (r > 0.9994), and the lower limit of quantification (LLOQ) was 2.5 ng/mL for both. Moreover, the intra- and interday precision relative standard deviation (RSD) of KET and NK were less than 4.31% and 6.53%, respectively. The accuracies (relative error) of KET and NK were below -1.41% and -6.07%, respectively. The extraction recoveries of KET and NK were more than 81.23 ± 3.45% and 80.42 ± 4.57%, respectively. This sensitive, rapid, and selective UPLC-MS/MS method was successfully applied to study the pharmacokinetic effects of l-THP on KET after gastric gavage. The results demonstrated that l-THP could increase the bioavailability of KET and promote the metabolism of KET. The results showed that l-THP has pharmacokinetics effects on KET in rat plasma.

Pharmacokinetic Study of Delavinone in Mice after Intravenous and Oral Administration by UPLC-MS/MS

Thirty-one compounds, including delavinone, were isolated from the methanol extract of F. cirrhosa by modern chromatographic techniques. The pharmacological action of Fritillaria is widely used in clinical practice. However, the pharmacokinetic studies on delavinone have not been reported. Therefore, the chemical constituents of this species were investigated. Therefore, it is necessary to establish an analytical method to monitor the concentration of delavinone. An UPLC-MS/MS method was established to determine delavinone in the mouse blood, and the pharmacokinetics of delavinone after intravenous (1.0 mg/kg) and intragastric (2.5, 10.0 mg/kg) administration were studied. The lower limit of quantification was 1.0 ng/mL. The intraday and interday precision RSD were less than 13%, the accuracy ranged from 96.8% to 104.9%, the average recovery was better than 80.6%, and the matrix effect was between 88.8% and 103.4%. The UPLC-MS/MS method has been successfully applied to the pharmacokinetics of delavinone in mice. The noncompartment model was used to fit the main pharmacokinetic parameters. It was found that AUC in mice was higher than that in mice given orally, and the bioavailability of delavinone was 12.4%.

Pharmacokinetics and Bioavailability Study of Tubeimoside I in ICR Mice by UPLC-MS/MS

The aim of this study is to establish and validate a rapid, selective, and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method to determine tubeimoside I (TBMS-I) in ICR (Institute of Cancer Research) mouse whole blood and its application in the pharmacokinetics and bioavailability study. The blood samples were precipitated by acetonitrile to extract the analytes. Chromatographic separation was performed on a UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm). The mobile phase consisted of water with 0.1% formic acid and methanol (1 : 1, v/v) at a flow rate of 0.4 mL/min. The total eluting time was 4 min. The TBMS-I and ardisiacrispin A (internal standard (IS)) were quantitatively detected by a tandem mass spectrometry equipped with an electrospray ionization (ESI) in a positive mode by multiple reaction monitoring (MRM). A validation of this method was in accordance with the US Food and Drug Administration (FDA) guidelines. The lower limit of quantification (LLOQ) of TBMS-I was 2 ng/mL, and the calibration curve was linearly ranged from 2 to 2000 ng/mL (r2 ≥ 0.995). The relative standard deviation (RSD) of interday precision and intraday precision was both lower than 15%, and the accuracy was between 91.7% and 108.0%. The average recovery was >66.9%, and the matrix effects were from 104.8% to 111.0%. In this assay, a fast, highly sensitive, and reproducible quantitative method was developed and validated in mouse blood for the first time. The absolute availability of TBMS-I in the mouse was only 1%, exhibiting a poor oral absorption.