Physiologically based pharmacokinetic modelling and simulation to predict the plasma concentration profile of schaftoside after oral administration of total flavonoids of Desmodium styracifolium

Determination of Schaftoside and Isoschaftoside in Rat Plasma Utilizing UPLC-MS/MS

To evaluate the pharmacokinetics, absolute bioavailability, and plasma concentrations of schaftoside and isoschaftoside in rats, an UPLC-MS/MS method was employed. For sample preparation, plasma proteins were precipitated using chilled methanol. The separation was achieved on a UPLC HSS T3 column with a mobile phase consisting of methanol and water (with 0.1% formic acid in water), at a flow rate of 0.4 mL/min. Detection was performed using electrospray ionization (ESI) in positive ion mode, coupled with multiple reaction monitoring (MRM) for quantitative analysis. Rats received oral doses of schaftoside (1 mg/kg) and isoschaftoside (5 mg/kg), and the pharmacokinetic profiles of both compounds were compared. The calibration curve for the method demonstrated excellent linearity within the concentration range of 1-2000 ng/mL, with correlation coefficients (r values) exceeding 0.99. Following intravenous and oral administration, significant differences were observed in the AUC(0-t) between schaftoside and isoschaftoside, whereas their half-lives (t1/2) remained comparable. The absolute bioavailability of schaftoside and isoschaftoside in rat plasma was determined to be 0.95% and 0.22%, respectively.

PBPK Modeling: Empowering Drug Development and Precision Dosing in China

Physiologically based pharmacokinetic (PBPK) modeling, a cornerstone of model-informed drug development and model-informed precision dosing, simulates drug disposition in the human body by integrating physiological, biochemical, and physicochemical parameters. While PBPK modeling has advanced globally since the 1970s, China's adoption of this technology has followed a distinctive path, characterized by accelerated growth over the past 2 decades. This review provides a comprehensive analysis of China's contributions to PBPK modeling, addressing knowledge gaps in publication trends, application domains, and platform preferences. A systematic literature search yielded 266 original PBPK research articles from PubMed up to August 08, 2024. The analysis revealed that drug disposition and drug-drug interaction studies constitute the largest proportion of PBPK analyses in China. Chinese universities and hospitals emerge as the leading contributors to PBPK research among institutions in China. Although established commercial PBPK platform such as GastroPlus and Simcyp remain popular within the Chinese pharmaceutical industry, open-source platforms like PK-Sim are gaining significant traction in PBPK applications across China. This review underscores the transformative potential of PBPK modeling in drug development within China, offering valuable insights into future directions and challenges in the field.

Comparisons of PK-Sim and R program for physiologically based pharmacokinetic model development for broiler chickens and laying hens: meloxicam as a case study

Physiologically based pharmacokinetic (PBPK) models play a critical role in evaluating drug residue concentrations and estimating withdrawal intervals (WDIs) for food-producing animals. These models are facilitated by various programming software (e.g. R program) and predefined PBPK platforms, such as Open Systems Pharmacology (OSP) suite integrated by PK-Sim and Mobi, which offers a user-friendly graphical interface. Both R and OSP are open-source software. However, there is a lack of comparative analyses of both platforms and their potential impact on PBPK models. This study aims to evaluate the influence of different platforms on PBPK workflow, parameters selection, and output results, which is exemplified via a case study for meloxicam in chickens in both platforms. Our findings indicate that while the choice of PBPK platforms affected the workflow and input parameters, the predictive performance of established models remained consistent across both platforms. Both platforms predicted meloxicam pharmacokinetics in plasma and tissues accurately across different exposure scenarios. The PBPK-estimated WDIs under various dosing regimens from both platforms were quite similar. Notable differences between OSP suite and R were primarily observed during sensitivity analysis and parameter identification processes, especially the time consumption. This study offers insight into software variances and their implications for translating PBPK modeling knowledge between users of 2 platforms. Also, it provides a PBPK model structure template implemented in both software platforms for food safety and risk assessment in poultry and a detailed tutorial on expanding the model structure in PK-Sim and Mobi.

Comprehensive Parent-Metabolite PBPK/PD Modeling Insights Into Methotrexate Personalized Dosing Strategies in Patients With Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a major public health concern, which can cause serious outcomes. Low-dose methotrexate (MTX) is a cornerstone in RA treatment, but there is significant heterogeneity in clinical response. To evaluate underlying sources of pharmacokinetic variability and clinical response of MTX, a physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) model was developed using PK-sim and Mobi (version 11.1). The PBPK model included metabolism and transportation by AXO1, FPGS, GGH, RFC, and MRP2, with renal and biliary excretion. We also developed various degrees of renal insufficiency populations with subsequent dosing optimizations. A total of 23 MTX plasma concentration-time profiles were used, with 97% of predicted plasma concentrations within a two-fold range compared to observed data. The PBPK/PD modeling and simulation demonstrated that variability in renal clearance and enzymes related to MTX are likely important drivers of PK variability and there is a quantitative relationship between MTX-PG3 and RA treatment response. The PBPK/PD model could be used to guide improvement in MTX dose regimens for RA patients.

Schaftoside improves HFpEF through regulation the autophagy-lysosome pathway by allosterically targeting CaMKII-δ

Heart failure with preserved ejection fraction (HFpEF) presents a significant challenge to global healthcare systems due to its complex presentation. HFpEF presents with a normal or near-normal left ventricular ejection fraction, cardiac diastolic dysfunction, and a metabolic profile characterized by impaired inflammation and oxidative stress. There have been few valuable drug targets reported for HFpEF to date. Here, we discovered that schaftoside, an active component from licorice, has a significant protective effect on the cardiac remodeling induced by continuous infusion of angiotensin II (AngII), which leads to the HFpEF phenotype. Mechanistically, schaftoside has demonstrated the ability to ameliorate lysosomal dysfunction in both in vitro and in vivo models, thereby activating autophagy. Bioinformatic analyses based on proteome and phosphoproteome suggested that Ca2+/calmodulin-dependent protein kinase II (CaMKII) was a potential target for schaftoside. It was confirmed that schaftoside allosterically mediated CaMKII-δ conformation via targeting a unique active pocket near the ATP-binding site to inhibit protein phosphorylation and regulate the lysosomal autophagy pathway. Therefore, schaftoside represents the first small molecule identified to inhibit CaMKII-δ activity through allosteric inhibition, providing a novel candidate for alleviating cardiac metabolic imbalance in HFpEF.

Transcriptome-associated metabolomics reveals the molecular mechanism of flavonoid biosynthesis in Desmodium styracifolium (Osbeck.) Merr under abiotic stress

The primary pharmacological components of Desmodium styracifolium (Osbeck.) Merr. are flavonoids, which have a broad range of pharmacological effects and are important in many applications. However, there have been few reports on the molecular mechanisms underlying flavonoid biosynthesis in the pharmacodynamic constituents of D. styracifolium. Flavonoid biosynthesis in D. styracifolium pharmacodynamic constituents has, however, been rarely studied. In this study, we investigated how salt stress, 6-BA (6-Benzylaminopurine) treatment, and PEG 6000-simulated drought stress affect flavonoid accumulation in D. styracifolium leaves. We integrated metabolomics and transcriptomic analysis to map the secondary metabolism regulatory network of D. styracifolium and identify key transcription factors involved in flavonoid biosynthesis. We then constructed overexpression vectors for the transcription factors and used them to transiently infiltrate Nicotiana benthamiana for functional validation. This experiment confirmed that the transcription factor DsMYB60 promotes the production of total flavonoids in Nicotiana tabacum L. leaves. This study lays the foundation for studying flavonoid biosynthesis in D. styracifolium at the molecular level. Furthermore, this study contributes novel insights into the molecular mechanisms involved in the biosynthesis of active ingredients in medicinal plants.

Simultaneous determination of plasma protein binding of five C-glycosylflavones from TFDS by rapid equilibrium dialysis

The total flavonoids of Desmodium styracifolium (TFDS) are flavonoid-rich extracts obtained from Desmodii Styracifolii Herba, which is approved for the treatment of urolithiasis in China. C-glycosylflavones including schaftoside, vicenin-1, vicenin-2, vicenin-3, and isovitexin are the main active constituents. In this study, the plasma protein binding of these compounds was determined for the first time in rat and human plasma by rapid equilibrium dialysis combined with HPLC-MS/MS method. The developed method was validated in terms of specificity, linearity, accuracy, precision, extraction effect, matrix effect, and stability. Schaftoside, vicenin-1, vicenin-2, and vicenin-3 exhibited moderate plasma protein binding, ranging from 56.6% to 61.5% in rat plasma and 55.0%-62.9% in human plasma. In comparison, isovitexin demonstrated a higher plasma protein binding in the range of 92.3-93.1% and 95.1-96.2% in rat and human plasma, respectively. Furthermore, the potential interactions mediated via plasma protein binding between isovitexin and nonsteroidal anti-inflammatory drugs (NSAIDs) were investigated by rapid equilibrium dialysis. No significant changes were observed, indicating a lower likelihood of interaction between TFDS and NSAIDs due to plasma protein binding in the treatment of urinary system disorders.

Pharmacokinetic and oral bioavailability study of schaftoside in rats

A simple and sensitive LC-tandem mass spectrometry method was established and validated for the determination of schaftoside in rat plasma. After prepared by protein precipitation with acetonitrile, schaftoside and internal standard were separated on a Waters HSS T3 column using acetonitrile containing 0.1% formic acid and 0.1% formic acid in water as the mobile phase by gradient elution. The method showed excellent linearity over the range of 0.5-500 ng/mL with acceptable intra- and inter-day precision, accuracy, matrix effect, and recovery. The stability assay indicated that schaftoside was stable during the sample acquisition, preparation, and storage. The method was applied to a pharmacokinetic study of schaftoside in rats. The result suggested that after intravenous administration at a dose of 1 mg/kg, schaftoside was quickly eliminated from the plasma with an elimination half-life of 0.58 h. After oral administration at doses of 5, 10, and 20 mg/kg, schaftoside was quickly absorbed into the plasma and reached the peak concentration (Cmax) of 45.1-104.99 ng/mL at 0.67-1.17 h. The increase of exposure (area under the curve) was linear with the increase of dose. The oral bioavailability was 0.42%-0.71% in the range of 5-20 mg/kg.

Prediction of pharmacokinetics of an anaplastic lymphoma kinase inhibitor in rat and monkey: application of physiologically based pharmacokinetic model as an alternative tool to minimise animal studies

The pharmacokinetic (PK) and toxicokinetic profile of a drug from its preclinical evaluation helps the researcher determine whether the drug should be tested in humans based on its safety and toxicity.Preclinical studies require time and resources and are prone to error. Moreover, according to the United States Food and Drug Administration Modernisation Act 2, animal testing is no longer mandatory for new drug development, and an animal-free alternative, such as cell-based assay and computer models, can be used.Different physiologically based PK models were developed for an anaplastic lymphoma kinase inhibitor in rats and monkeys after intravenous and oral administration using its physicochemical properties and in vitro characterisation data.The developed model was validated against the in vivo data available in the literature, and the validation results were found within the acceptable limit. A parameter sensitivity analysis was performed to identify the properties of the compound influencing the PK profile.This work demonstrates the application of the physiologically based PK model to predict the PKs of a drug, which will eventually assist in reducing the number of animal studies and save time and cost of drug discovery and development.