Assessment of Herb-Drug Interaction Potential of Five Common Species of Licorice and Their Phytochemical Constituents

The dried roots and rhizomes of Glycyrrhiza species (G. glabra, G. uralensis and G. inflata), commonly known as licorice, have long been used in traditional medicine. In addition, two other species, G. echinata and G. lepidota are also considered "licorice" in select markets. Currently, licorice is an integral part of several botanical drugs and dietary supplements. To probe the botanicals' safety, herb-drug interaction potential of the hydroethanolic extracts of five Glycyrrhiza species and their key constituents was investigated by determining their effects on pregnane X receptor, aryl hydrocarbon receptor, two major cytochrome P450 isoforms (CYP3A4 and CYP1A2), and the metabolic clearance of antiviral drugs. All extracts enhanced transcriptional activity of PXR and AhR (>2-fold) and increased the enzyme activity of CYP3A4 and CYP1A2. The highest increase in CYP3A4 was seen with G. echinata (4-fold), and the highest increase in CYP1A2 was seen with G. uralensis (18-fold) and G. inflata (16-fold). Among the constituents, glabridin, licoisoflavone A, glyasperin C, and glycycoumarin activated PXR and AhR, glabridin being the most effective (6- and 27-fold increase, respectively). Licoisoflavone A, glyasperin C, and glycycoumarin increased CYP3A4 activity while glabridin, glyasperin C, glycycoumarin, and formononetin increased CYP1A2 activity (>2-fold). The metabolism of antiretroviral drugs (rilpivirine and dolutegravir) was increased by G. uralensis (2.0 and 2.5-fold) and its marker compound glycycoumarin (2.3 and 1.6-fold). The metabolism of dolutegravir was also increased by G. glabra (2.8-fold) but not by its marker compound, glabridin. These results suggest that licorice and its phytochemicals could affect the metabolism and clearance of certain drugs that are substrates of CYP3A4 and CYP1A2.Supplemental data for this article is available online at https://doi.org/10.1080/19390211.2022.2050875 .

Metabolic Pathway of Icotinib In Vitro: The Differential Roles of CYP3A4, CYP3A5, and CYP1A2 on Potential Pharmacokinetic Drug-Drug Interaction

Icotinib is the first self-developed small molecule drug in China for targeted therapy of non-small cell lung cancer. To date, systematic studies on the pharmacokinetic drug-drug interaction of icotinib were limited. By identifying metabolite generated in human liver microsomes and revealing the contributions of major cytochromes P450 (CYPs) in the formation of major metabolites, the aim of the present work was to understand the mechanisms underlying pharmacokinetic and pharmacological variability in clinic. A liquid chromatography/UV/high-resolution mass spectrometer method was developed to characterize the icotinib metabolites. The formation of 6 major metabolites was studied in recombinant CYP isozymes and human liver microsomes with specific inhibitors to identify the CYPs responsible for icotinib metabolism. The metabolic pathways observed in vitro are consistent with those observed in human. Results demonstrated that the metabolites are predominantly catalyzed by CYP3A4 (77%∼87%), with a moderate contribution from CYP3A5 (5%∼15%) and CYP1A2 (3.7%∼7.5%). The contribution of CYP2C8, 2C9, 2C19, and 2D6 is insignificant. Based on our observations, to minimize drug-drug interaction risk in clinic, coprescription of icotinib with strong CYP3A inhibitors or inducers must be weighed. CYP1A2, a highly inducible enzyme in the smoking population, may also represent a determinant of pharmacokinetic and pharmacological variability of icotinib, especially in lung cancer patients with smoking history.

Evaluation of a New Molecular Entity as a Victim of Metabolic Drug-Drug Interactions-an Industry Perspective

Under the guidance of the International Consortium for Innovation and Quality in Pharmaceutical Development (IQ), scientists from 20 pharmaceutical companies formed a Victim Drug-Drug Interactions Working Group. This working group has conducted a review of the literature and the practices of each company on the approaches to clearance pathway identification (fCL), estimation of fractional contribution of metabolizing enzyme toward metabolism (fm), along with modeling and simulation-aided strategy in predicting the victim drug-drug interaction (DDI) liability due to modulation of drug metabolizing enzymes. Presented in this perspective are the recommendations from this working group on: 1) strategic and experimental approaches to identify fCL and fm, 2) whether those assessments may be quantitative for certain enzymes (e.g., cytochrome P450, P450, and limited uridine diphosphoglucuronosyltransferase, UGT enzymes) or qualitative (for most of other drug metabolism enzymes), and the impact due to the lack of quantitative information on the latter. Multiple decision trees are presented with stepwise approaches to identify specific enzymes that are involved in the metabolism of a given drug and to aid the prediction and risk assessment of drug as a victim in DDI. Modeling and simulation approaches are also discussed to better predict DDI risk in humans. Variability and parameter sensitivity analysis were emphasized when applying modeling and simulation to capture the differences within the population used and to characterize the parameters that have the most influence on the prediction outcome.

Alcohol consumption effect on antiretroviral therapy and HIV-1 pathogenesis: role of cytochrome P450 isozymes

INTRODUCTION

Alcohol consumption, which is highly prevalent in HIV-infected individuals, poses serious concerns in terms of rate of acquisition of HIV-1 infection, HIV-1 replication, response to highly active antiretroviral therapy (HAART) and AIDS/neuroAIDS progression. However, little is known about the mechanistic pathways by which alcohol exerts these effects, especially with respect to HIV-1 replication and the patient's response to HAART.

AREAS COVERED

In this review, the authors discuss the effects of alcohol consumption on HIV-1 pathogenesis and its effect on HAART. They also describe the role of cytochrome P450 2E1 (CYP2E1) in alcohol-mediated oxidative stress and toxicity, and the role of CYP3A4 in the metabolism of drugs used in HAART (i.e., protease inhibitors (PI) and non-nucleoside reverse transcriptase inhibitors (NNRTI)). Based on the most recent findings the authors discuss the role of CYP2E1 in alcohol-mediated oxidative stress in monocytes/macrophages and astrocytes, as well as the role of CYP3A4 in alcohol-PI interactions leading to altered metabolism of PI in these cells.

EXPERT OPINION

The authors propose that alcohol and PI/NNRTI interact synergistically in monocytes/macrophages and astrocytes through the CYP pathway leading to an increase in oxidative stress and a decrease in response to HAART. Ultimately, this exacerbates HIV-1 pathogenesis and neuroAIDS.

Lack of drug interaction between the migraine drug MAP0004 (orally inhaled dihydroergotamine) and a CYP3A4 inhibitor in humans

BACKGROUND

Dihydroergotamine (DHE), a proven migraine treatment, currently has product labeling warning against concomitant use of CYP3A4 inhibitors because of potential drug interactions. However, no reported studies of such interactions with DHE administered by any route are available.

METHODS

The pharmacokinetics (PK) of MAP0004, an investigative inhaled DHE formulation, were assessed in human subjects with and without CYP3A4 inhibition by ketoconazole to evaluate the potential for drug interaction, elevation of DHE levels, and increased adverse effects.

RESULTS

After MAP0004 alone vs. MAP0004 plus ketoconazole, the DHE maximum concentrations (C(max)) and area-under-the-curve (AUC(0-48) and AUC(0-∞)) were not statistically significantly different nor was the C(max) of the primary metabolite, 8'-OH-DHE. A difference in 8'-OH-DHE AUCs was observed between MAP0004 with and without ketoconazole; however, the concentrations were very low. MAP0004 was well tolerated after both treatments.

CONCLUSIONS

This study demonstrated that CYP3A4 inhibition had little to no effect on DHE PK after MAP0004 administration, apparently because of its high systemic and low gastrointestinal bioavailability. CYP3A4 inhibition slowed elimination of the metabolite 8'-OH-DHE, but concentrations were too low to be pharmacologically relevant.

Pharmacokinetic and pharmacodynamic evaluation of the novel CCR1 antagonist CCX354 in healthy human subjects: implications for selection of clinical dose

The safety and pharmacokinetic (PK)/pharmacodynamic (PD) profile of the novel CCR1 antagonist CCX354 was evaluated in double-blind, placebo-controlled, single- and multiple-dose phase I studies (1-300 mg/day oral doses). CCX354 was well tolerated and displayed a linear dose-exposure profile, with half-life approaching 7 h at the 300-mg dose. The extent of CCR1 receptor blockade on blood monocytes, which correlated well with plasma concentrations of the drug, was assessed using fluorescently labeled CCL3 binding in whole blood from phase I subjects. High levels of receptor coverage at the 12-h time point were achieved after a single dose of 100 mg CCX354. Preclinical studies indicate that effective blockade of inflammatory cell infiltration into tissues requires ≥90% CCR1 inhibition on blood leukocytes at all times. The comparison of the properties of CCX354 with those published for other CCR1 antagonists has informed the dose selection for ongoing clinical development of CCX354 in rheumatoid arthritis (RA).

Characterization of CCX282-B, an orally bioavailable antagonist of the CCR9 chemokine receptor, for treatment of inflammatory bowel disease

The chemokine system represents a diverse group of G protein-coupled receptors responsible for orchestrating cell recruitment under both homeostatic and inflammatory conditions. Chemokine receptor 9 (CCR9) is a chemokine receptor known to be central for migration of immune cells into the intestine. Its only ligand, CCL25, is expressed at the mucosal surface of the intestine and is known to be elevated in intestinal inflammation. To date, there are no reports of small-molecule antagonists targeting CCR9. We report, for the first time, the discovery of a small molecule, CCX282-B, which is an orally bioavailable, selective, and potent antagonist of human CCR9. CCX282-B inhibited CCR9-mediated Ca(2+) mobilization and chemotaxis on Molt-4 cells with IC(50) values of 5.4 and 3.4 nM, respectively. In the presence of 100% human serum, CCX282-B inhibited CCR9-mediated chemotaxis with an IC(50) of 33 nM, and the addition of α1-acid glycoprotein did not affect its potency. CCX282-B inhibited chemotaxis of primary CCR9-expressing cells to CCL25 with an IC(50) of 6.8 nM. CCX282-B was an equipotent inhibitor of CCL25-directed chemotaxis of both splice forms of CCR9 (CCR9A and CCR9B) with IC(50) values of 2.8 and 2.6 nM, respectively. CCX282-B also inhibited mouse and rat CCR9-mediated chemotaxis. Inhibition of CCR9 with CCX282-B results in normalization of Crohn's disease such as histopathology associated with the TNF(ΔARE) mice. Analysis of the plasma level of drug associated with this improvement provides an understanding of the pharmacokinetic/pharmacodynamic relationship for CCR9 antagonists in the treatment of intestinal inflammation.