Establishment of rat liver microsome-hydrogel system for in vitro phase II metabolism and its application to study pharmacological effects of UGT substrates

Modulation of diverse oncogenic signaling pathways by oroxylin A: An important strategy for both cancer prevention and treatment

BACKGROUND

Regardless of major advances in diagnosis, prevention and treatment strategies, cancer is still a foreboding cause due to factors like chemoresistance, radioresistance, adverse side effects and cancer recurrence. Therefore, continuous development of unconventional approaches is a prerequisite to overcome foregoing glitches. Natural products have found their way into treatment of serious health conditions, including cancer since ancient times. The compound oroxylin A (OA) is one among those with enormous potential against different malignancies. It is a flavonoid obtained from the several plants such as Oroxylum indicum, Scutellaria baicalensis and S. lateriflora, Anchietea pyrifolia, and Aster himalaicus.

PURPOSE

The main purpose of this study is to comprehensively elucidate the anticancerous effects of OA against various malignancies and unravel their chemosensitization and radiosensitization potential. Pharmacokinetic and pharmacodynamic studies of OA have also been investigated.

METHOD

The literature on antineoplastic effects of OA was searched in PubMed and Scopus, including in vitro and in vivo studies and is summarized based on a systematic review protocol prepared according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The term "oroxylin A" was used in combination with "cancer" and all the title, abstracts and keywords appeared were considered.

RESULTS

In Scopus, a total of 157 articles appeared out of which 103 articles that did not meet the eligibility criteria were eliminated and 54 were critically evaluated. In PubMed, from the 85 results obtained, 26 articles were eliminated and 59 were included in the preparation of this review. Mounting number of studies have illustrated the anticancer effects of OA, and its mechanism of action.

CONCLUSION

OA is a promising natural flavonoid possessing wide range of pleiotropic properties and is a potential anticancer agent. It has a great potential in the treatment of multiple cancers including brain, breast, cervical, colon, esophageal, gall bladder, gastric, hematological, liver, lung, oral, ovarian, pancreatic and skin. However, lack of pharmacokinetic studies, toxicity assessments, and dose standardization studies and adverse effects limit the optimization of this compound as a therapeutic agent.

Development of vericiguat: The first soluble guanylate cyclase (sGC) stimulator launched for heart failure with reduced ejection fraction (HFrEF)

In recent years, with improvements in treatments for heart failure (HF), the survival period of patients has been extended. However, the emergence of some patients with repeated hospitalizations due to their worsening conditions and low survival rates followed. Currently, few drugs are available for such patients. Vericiguat was first drug approved for the treatment of symptomatic patients with chronic HF with reduced ejection fraction (HFrEF) to reduce the occurrence of worsening HF. This article provides comprehensive information about vericiguat in terms of drug design and development, structure-activity relationship (SAR), synthesis, pharmacological efficacy, and clinical practice. In addition, insights into the current vericiguat trials and treatments of HF are also discussed.

A Novel Method for Predicting the Human Inherent Clearance and Its Application in the Study of the Pharmacokinetics and Drug-Drug Interaction between Azidothymidine and Fluconazole Mediated by UGT Enzyme

In order to improve the benefit–risk ratio of pharmacokinetic (PK) research in the early development of new drugs, in silico and in vitro methods were constructed and improved. Models of intrinsic clearance rate (CL_int) were constructed based on the quantitative structure–activity relationship (QSAR) of 7882 collected compounds. Moreover, a novel in vitro metabolic method, the Bio-PK dynamic metabolic system, was constructed and combined with a physiology-based pharmacokinetic model (PBPK) model to predict the metabolism and the drug–drug interaction (DDI) of azidothymidine (AZT) and fluconazole (FCZ) mediated by the phase II metabolic enzyme UDP-glycosyltransferase (UGT) in humans. Compared with the QSAR models reported previously, the goodness of fit of our CL_int model was slightly improved (determination coefficient (R²) = 0.58 vs. 0.25–0.45). Meanwhile, compared with the predicted clearance of 61.96 L/h (fold error: 2.95–3.13) using CL_int (8 µL/min/mg) from traditional microsomal experiment, the predicted clearance using CL_int (25 μL/min/mg) from Bio-PK system was increased to 143.26 L/h (fold error: 1.27–1.36). The predicted C_max and AUC (the area under the concentration–time curve) ratio were 1.32 and 1.84 (fold error: 1.36 and 1.05) in a DDI study with an inhibition coefficient (Ki) of 13.97 μM from the Bio-PK system. The results indicate that the Bio-PK system more truly reflects the dynamic metabolism and DDI of AZT and FCZ in the body. In summary, the novel in silico and in vitro method may provide new ideas for the optimization of drug metabolism and DDI research methods in early drug development.

Study of Pharmaceutical Excipient PEG400 Alteration of Pharmacokinetics and Tissue Distribution of Main Flavonoids Metabolites of Baicalin

Background::

Polyethylene glycol 400 (PEG400), as a good traditional Chinese medicine solvent, diluent and solubilizer, is widely used as a main pharmaceutical excipient in traditional Chinese medicine compound preparations containing active ingredient baicalin. PEG400 could increase the solubility and release of baicalin in vivo, but it was unknown that PEG400 affected the absorption and distribution of baicalin or not.

Objective: :

At present, the effects of PEG400 on the pharmacokinetic characteristics and tissue distribution behaviors of the main flavonoid metabolites baicalin, baicalein 6-O-β-D-glucopyranoside (B6G) and baicalein after oral administration of baicalin were investigated by a rapid, efficient and sensitive ultra- high performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method. Moreover, we respectively studied the effects of PEG400 on the activities and protein expressions of two subtypes UDP-glucuronyltransferase 1 A8/A9 (UGT1A8 and UGT1A9) of UDP-glucuronosyltransferases (UGTs) in vitro and in vivo experiments to determine the partial mechanisms by which PEG400 altered the pharmacokinetics and tissue distribution behaviors of the three flavonoid metabolites.

Methods:

A rapid, efficient and sensitive ultra-high performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method and ELISA and so on.

Results:

The results showed that PEG400 significantly increased the Cmax and AUC0-t values (P < 0.05 or P < 0.01) of baicalin and B6G while baicalein could not be quantified due to its extremely low concentration (lower the LLOQ) in plasma. Baicalin, B6G and baicalein were mainly distributed in the stomach, small intestine, kidney and liver. PEG400 changed the distribution of three flavonoid metabolites in various tissues and also increased the activities and expressions of UGT1A8 and UGT1A9.

Conclusion::

In conclusion, PEG400 significantly altered the pharmacokinetic characteristics and tissue distribution behaviors of three flavonoid metabolites may partly result from PEG400 upregulated the activities and expressions of the drug biphasic metabolic enzymes UGT1A8 and UGT1A9, which provided a material basis and useful information to reveal the mechanism of action and clinical application of PEG400.

Poly (ethylene glycol)-block-poly (D, L-lactide) (PEG-PLA) micelles for brain delivery of baicalein through nasal route for potential treatment of neurodegenerative diseases due to oxidative stress and inflammation: An in vitro and in vivo study

The application of baicalein (BE) in central nervous system (CNS) neurodegenerative diseases is hampered by its poor solubility and low oral bioavailability despite its neuroprotective effects. In this study, BE was encapsulated into poly (ethylene glycol)-block-poly (D, L-lactide) micelles (BE-MC) and administrated through nasal inhalation to enhance its brain distribution. BE-MC showed comparable in-vitro antioxidant activity to BE solution. Cytotoxicity study illustrated BE-MC could reduce BE's toxicity in SH-SY5Y cells and BV-2 cells. BE solution at concentration higher than 5 µM caused significant BV-2 cells' death after stimulation of LPS while BE-MC were non-toxic to cells at concentrations up to 50 µM. BE solution at 5 µM had no anti-inflammatory effects in BV-2 cells while BE-MC could reduce the inflammatory factor TNF-α at 5 µM and IL-6 at 20 µM significantly. Pharmacokinetic studies in C57BL/6 mice showed the absolute AUC values of BE in plasma and brain of BE-MC through nasal inhalation group were 5.09-fold and 1.50-fold higher than that of BE coarse powder through oral administration group at the same dose. Thus, our study indicated BE-MC administered nasally could be useful for treatment of CNS neurodegenerative diseases due to oxidative stress and inflammation.

Inhibition of UDP-glucuronosyltransferases by different furoquinoline alkaloids

Herbs are often administered in combination with therapeutic drugs, raising the possibility for herb-drug interactions (HDIs). Furoquinoline alkaloids are found in Rutaceae plants, which are structurally similar and have many medicinal properties. This study aims to investigate the inhibition of four furoquinoline alkaloids on the activity of UDP-glucuronosyltransferases (UGTs).The recombinant UGTs-catalyzed glucuronidation metabolism of 4-methylumbelliferone (4-MU) was utilized to investigate the inhibition potential. Inhibition type and parameters were determined, and in silico docking was employed to elucidate the inhibition difference of furoquinoline alkaloids towards UGTs.Dictamine, haplopine, γ-fagarine and skimmianine strongly inhibited UGT1A3, UGT1A7, UGT1A9 and UGT2B4, respectively. Among them, dictamnine inhibited more than 70% of the four UGTs. Inhibition kinetics determination showed that they all exerted competitive inhibition, and the inhibition kinetic constant (K_i) was determined to be 8.3, 7.2, 3.7 and 33.9 μM, respectively. In vitro-in vivo extrapolation (IVIVE) was employed to demonstrate the inhibition possibility for four alkaloids. Skimmianine was proved to be more suitable for clinical application. In silico docking study indicated that the hydrophobic interactions played a key role in the inhibition of furoquinoline alkaloids towards three of the four UGTs. In conclusion, monitoring the interactions between furoquinoline alkaloids and drugs mainly undergoing UGTs-catalyzed metabolism is necessary.