Evaluation of Cytochrome P450-Mediated Cannabinoid-Drug Interactions in Healthy Adult Participants.

Understanding cannabis-drug interactions is critical given regulatory changes that have increased access to and use of cannabis. Cannabidiol (CBD) and Δ-9-tetrahydrocannabinol (Δ9-THC), the most abundant phytocannabinoids, are in vitro reversible and time-dependent (CBD only) inhibitors of several cytochrome P450 (CYP) enzymes. Cannabis extracts were used to evaluate quantitatively potential pharmacokinetic cannabinoid-drug interactions in 18 healthy adults. Participant received, in a randomized cross-over manner (separated by ≥ 1 week), a brownie containing (i) no cannabis extract (ethanol/placebo), (ii) CBD-dominant cannabis extract (640 mg CBD + 20 mg Δ9-THC), or (iii) Δ9-THC-dominant cannabis extract (20 mg Δ9-THC and no CBD). After 30 minutes, participants consumed a cytochrome P450 (CYP) drug cocktail consisting of caffeine (CYP1A2), losartan (CYP2C9), omeprazole (CYP2C19), dextromethorphan (CYP2D6), and midazolam (CYP3A). Plasma and urine samples were collected (0-24 hours). The CBD + Δ9-THC brownie inhibited CYP2C19 > CYP2C9 > CYP3A > CYP1A2 (but not CYP2D6) activity, as evidenced by an increase in the geometric mean ratio of probe drug area under the plasma concentration-time curve (AUC) relative to placebo (AUCGMR ) of omeprazole, losartan, midazolam, and caffeine by 207%, 77%, 56%, and 39%, respectively. In contrast, the Δ9-THC brownie did not inhibit any of the CYPs. The CBD + Δ9-THC brownie increased Δ9-THC AUCGMR by 161%, consistent with CBD inhibiting CYP2C9-mediated oral Δ9-THC clearance. Except for caffeine, these interactions were well-predicted by our physiologically-based pharmacokinetic model (within 26% of observed interactions). Results can be used to help guide dose adjustment of drugs co-consumed with cannabis products and the dose of CBD in cannabis products to reduce interaction risk with Δ9-THC.

The Impact of Suboptimal 25-Hydroxyvitamin D Levels and Cholecalciferol Replacement on the Pharmacokinetics of Oral Midazolam in Control Subjects and Patients With Chronic Kidney Disease.

The aim of this study was to investigate the impact of suboptimal 25-hydroxyvitamin D (25-VitD) and cholecalciferol (VitD3 ) supplementation on the pharmacokinetics of oral midazolam (MDZ) in control subjects and subjects with chronic kidney disease (CKD). Subjects with CKD (n = 14) and controls (n = 5) with suboptimal 25-VitD levels (<30 ng/mL) were enrolled in a 2-phase study. In phase 1 (suboptimal), subjects were administered a single oral dose of VitD3 (5000 IU) and MDZ (2 mg). In phase 2 (replete) subjects who achieved 25-VitD repletion after receiving up to 16 weeks of daily cholecalciferol were given the identical single oral doses of VitD3 and MDZ as in phase 1. Concentrations of MDZ and metabolites, 1'-hydroxymidazolam (1'-OHMDZ), and 1'-OHMDZ glucuronide (1'-OHMDZ-G) were measured by liquid chromatography-tandem mass spectrometry and pharmacokinetic analysis was performed. Under suboptimal 25-VitD, reductions in MDZ clearance and renal clearance of 47% and 87%, respectively, and a 72% reduction in renal clearance of 1'-OHMDZ-G were observed in CKD vs controls. In phase 1 versus phase 2, MDZ clearance increased in all control subjects, with a median (interquartile range) increase of 10.5 (0.62-16.7) L/h. No changes in MDZ pharmacokinetics were observed in subjects with CKD between phases 1 and 2. The effects of 25-VitD repletion on MDZ disposition was largely observed in subjects without kidney disease. Impaired MDZ metabolism and/or excretion alterations due to CKD in a suboptimal 25-VitD state may not be reversed by cholecalciferol therapy. Suboptimal 25-VitD may augment the reductions in MDZ and 1'-OHMDZ-G clearance values observed in patients with CKD.

[Effect of Laportea bulbifera extract on CYP450 enzyme activities in rats by Cocktail probe drug method].

The Cocktail probe drug method was used to evaluate the effect of Laportea bulbifera extract on the different subtypes of CYP450 enzyme activities in rats, and to provide references for its clinical rational drug use. The rats were randomly divided into a high-dose L. bulbifera group(0.45 g·kg~(-1)·d~(-1)) and a low-dose L. bulbifera group(0.09 g·kg~(-1)·d~(-1)). After continuous gavage for 7 and 14 days, the Cocktail probe mixing solution, including caffeine, midazolam, tolbutamide, omeprazole, metoprolol, and chlorzoxazone, was injected into the tail vein, and the blood sample was obtained from the tail vein at different time points. Ultra-high performance liquid chromatography-mass spectrometry(UPLC-MS) was established to determine the concentration of six probe drugs in rat plasma. DAS 2.0 was used to calculate its pharmacokinetic parameters, and the effect of L. bulbifera extract on CYP1 A2, CYP2 C9, CYP2 C19, CYP2 D6, CYP2 E1, and CYP3 A4 in rats was investigated. As compared with the blank control group, under the omeprazole index, the AUC_(0-t) and AUC_(0-∞) of the 7-day administration groups and the 14-day high-dose group were significantly decreased, and the CLz and Vz were significantly increased. Under the midazolam index, the AUC_(0-t) and AUC_(0-∞) of the 7-day low-dose group and the 14-day administration group were significantly decreased, and the CLz was significantly increased. In addition, the AUC_(0-∞) of the 7-day high-dose group was also significantly decreased. Under the index of metoprolol, the AUC_(0-t) and AUC_(0-∞) of each experimental group were decreased significantly, and the CLz and Vz of the 7-day low-dose group and the 14-day low-dose group were increased significantly. Under the caffeine index, the AUC_(0-t) and AUC_(0-∞) of the 7-day administration groups were increased significantly, the CLz was decreased significantly, and the t_(1/2 z) of the 14-day high-dose group was increased significantly. Under the chlorzoxazone index, the AUC_(0-t) and AUC_(0-∞) of the 7-day low-dose group were increased significantly, and the CLz was decreased significantly. Under the tolbutamide index, there was no statistical difference in the pharmacokinetic parameters. In conclusion, L. bulbifera extract induces the activities of CYP2 C19, CYP3 A4, and CYP2 D6, inhibits the activities of CYP1 A2 and CYP2 E1, and does not affect the activity of CYP2 C9.

Influence of Proteome Profiles and Intracellular Drug Exposure on Differences in CYP Activity in Donor-Matched Human Liver Microsomes and Hepatocytes.

Human liver microsomes (HLM) and human hepatocytes (HH) are important in vitro systems for studies of intrinsic drug clearance (CLint) in the liver. However, the CLint values are often in disagreement for these two systems. Here, we investigated these differences in a side-by-side comparison of drug metabolism in HLM and HH prepared from 15 matched donors. Protein expression and intracellular unbound drug concentration (Kpuu) effects on the CLint were investigated for five prototypical probe substrates (bupropion-CYP2B6, diclofenac-CYP2C9, omeprazole-CYP2C19, bufuralol-CYP2D6, and midazolam-CYP3A4). The samples were donor-matched to compensate for inter-individual variability but still showed systematic differences in CLint. Global proteomics analysis outlined differences in HLM from HH and homogenates of human liver (HL), indicating variable enrichment of ER-localized cytochrome P450 (CYP) enzymes in the HLM preparation. This suggests that the HLM may not equally and accurately capture metabolic capacity for all CYPs. Scaling CLint with CYP amounts and Kpuu could only partly explain the discordance in absolute values of CLint for the five substrates. Nevertheless, scaling with CYP amounts improved the agreement in rank order for the majority of the substrates. Other factors, such as contribution of additional enzymes and variability in the proportions of active and inactive CYP enzymes in HLM and HH, may have to be considered to avoid the use of empirical scaling factors for prediction of drug metabolism.

Validation of a HPLC method for quantification of midazolam in rat plasma: Application during a Maytenus ilicifolia-drug interaction study.

Midazolam (MDZ) is routinely employed as a marker compound of cytochrome P450 3A (CYP3A) activity. Despite the many HPLC-UV methods described to quantify MDZ in plasma, all of them use acetonitrile (ACN) or a mixture of methanol-isopropanol as organic solvent of the mobile phase. Since the ACN shortage in 2008, efforts have been made to replace this solvent during HPLC analysis. A simple, sensitive, accurate and repeatable HPLC-UV method (220 nm) was developed and validated to quantify MDZ in rat plasma using methanol instead. The method was applied during a herb-drug interaction study involving Maytenus ilicifolia, a Brazilian folk medicine used to treat gastric disorders. Plasma samples were alkalinized and MDZ plus alprazolam (internal standard) were extracted with diethyl ether. After solvent removal, the residue was reconstituted with methanol-water (1:1). The analyte was eluted throughout a C18 column using sodium acetate buffer (10 mm, pH 7.4)-methanol (40:60, v/v). The precision at the lower limit of quantification never exceeded 19.40%, and 13.86% at the higher levels of quality control standards, whereas the accuracy ranged from -19.81 to 14.33%. The analytical curve was linear from 50 to 2,000 ng/ml. The activity of the hepatic CYP3A enzymes was not affected by the extract.

A Short Exploration of Selected Sensitive CYP3A4 Substrates (Probe Drug).

BACKGROUND: CYP450 enzymes in the liver have a significant role in the metabolism of xenobiotics. Probe drug strategy is broadly used to evaluate the pharmacodynamic and pharmacokinetic drug/ herb-drug interactions/ food-drug interactions. Probe drugs reveal the exact pathway of drug metabolism in the liver by their targeted tractability property. The CYP3A4 isoenzyme metabolizes the majority of the drugs (65%). METHODS: The characteristics of targeted probe drugs were observed from the admetSAR (version2) online database. RESULTS: Midazolam is widely used as a probe drug because of its peculiar character. Midazolam affirms the accurate and consistent prediction of pharmacokinetic mediated drug interactions even in nanogram concentrations with or without a potent CYP3A inhibitor. Remarkably, midazolam is used as a CYP3A4 substrate in the majority of in vivo studies. CONCLUSION: It is concluded that midazolam shows a good response in all clinical studies because of its lesser half-life and bioavailability when compared with other probe drugs.

Assessing Transporter-Mediated Natural Product-Drug Interactions Via In vitro-In Vivo Extrapolation: Clinical Evaluation With a Probe Cocktail.

The botanical natural product goldenseal can precipitate clinical drug interactions by inhibiting cytochrome P450 (CYP) 3A and CYP2D6. Besides P-glycoprotein, effects of goldenseal on other clinically relevant transporters remain unknown. Established transporter-expressing cell systems were used to determine the inhibitory effects of a goldenseal extract, standardized to the major alkaloid berberine, on transporter activity. Using recommended basic models, the extract was predicted to inhibit the efflux transporter BCRP and uptake transporters OATP1B1/3. Using a cocktail approach, effects of the goldenseal product on BCRP, OATP1B1/3, OATs, OCTs, MATEs, and CYP3A were next evaluated in 16 healthy volunteers. As expected, goldenseal increased the area under the plasma concentration-time curve (AUC0-inf ) of midazolam (CYP3A; positive control), with a geometric mean ratio (GMR) (90% confidence interval (CI)) of 1.43 (1.35-1.53). However, goldenseal had no effects on the pharmacokinetics of rosuvastatin (BCRP and OATP1B1/3) and furosemide (OAT1/3); decreased metformin (OCT1/2, MATE1/2-K) AUC0-inf (GMR, 0.77 (0.71-0.83)); and had no effect on metformin half-life and renal clearance. Results indicated that goldenseal altered intestinal permeability, transport, and/or other processes involved in metformin absorption, which may have unfavorable effects on glucose control. Inconsistencies between model predictions and pharmacokinetic outcomes prompt further refinement of current basic models to include differential transporter expression in relevant organs and intestinal degradation/metabolism of the precipitant(s). Such refinement should improve in vitro-in vivo prediction accuracy, contributing to a standard approach for studying transporter-mediated natural product-drug interactions.

Characterization of red ginseng-drug interaction by CYP3A activity increased in high dose administration in mice.

Ginseng (Panax ginseng Meyer) is a popular traditional herbal medicine used worldwide. Patients often take ginseng preparations with other medicines where the ginseng dose could exceed the recommended dose during long-term administration. However, ginseng-drug interactions at high doses of ginseng are poorly understood. This study showed the possibility of herb-drug interactions between the Korean red ginseng (KRG) extract and cytochrome P450 (CYP) substrates in higher administration in mice. The CYP activities were determined in vivo after oral administration of KRG extract doses of 0.5, 1.0, and 2.0 g/kg for 2 or 4 weeks by monitoring the concentration of five CYP substrates/metabolites in the blood. The area under the curve for OH-midazolam/midazolam catalysed by CYP3A was increased significantly by the administration of 2.0 g/kg KRG extract for 2 and 4 weeks. CYP3A-catalysed midazolam 1'-hydroxylation also increased significantly in a dose- and time-dependent manner in the S9 fraction of mouse liver which was not related to induction by transcription. Whereas CYP2D-catalysed dextromethorphan O-deethylation decreased in a dose- and time-dependent manner in vivo. In conclusion, interactions were observed between KRG extract and CYP2D and CYP3A substrates at subchronic-high doses of KRG administration in mice.

Effect of High-Dose Esomeprazole on CYP1A2, CYP2C19, and CYP3A4 Activities in Humans: Evidence for Substantial and Long-lasting Inhibition of CYP2C19.

In vitro, esomeprazole is a time-dependent inhibitor of CYP2C19. Additionally, racemic omeprazole induces CYP1A2 and omeprazole and its metabolites inhibit CYP3A4 in vitro. In this 5-phase study, 10 healthy volunteers ingested 20 mg pantoprazole, 0.5 mg midazolam, and 50 mg caffeine as respective index substrates for CYP2C19, 3A4, and 1A2 before and 1, 25, 49 (pantoprazole only), and 73 hours after an 8-day pretreatment with 80 mg esomeprazole twice daily. The area under the plasma concentration-time curve (AUC) of R-pantoprazole increased 4.92-fold (90% confidence interval (CI) 3.55-6.82), 2.31-fold (90% CI 1.85-2.88), and 1.33-fold (90% CI 1.06-1.68) at the 1-hour, 25-hour, and 73-hour phases, respectively, consistent with a substantial and persistent inhibition of CYP2C19. The AUC of midazolam increased up to 1.44-fold (90% CI 1.22-1.72) and the paraxanthine/caffeine metabolic ratio up to 1.19-fold (90% CI 1.04-1.36), when the index substrates were taken 1 hour after esomeprazole. Based on the recovery of R-pantoprazole oral clearance, the turnover half-life of CYP2C19 was estimated to average 53 hours. Pharmacokinetic simulation based on the observed concentrations of esomeprazole and its metabolites as well as their published CYP2C19 inhibitory constants was well in line with the observed changes in R-pantoprazole pharmacokinetics during the course of the study. Extrapolations assuming linear pharmacokinetics of esomeprazole suggested weak to moderate inhibition at 20 and 40 mg twice daily dosing. In conclusion, high-dose esomeprazole can cause strong inhibition of CYP2C19, but only weakly inhibits CYP3A4 and leads to minor induction of CYP1A2. The enzymatic activity of CYP2C19 recovers gradually in ~ 3-4 days after discontinuation of esomeprazole treatment.

Evaluation of Erythromycin as a Tool to Assess CYP3A Contribution of Low Clearance Compounds in a Long-Term Hepatocyte Culture.

Long-term hepatocyte culture systems such as HepatoPac are well suited to evaluate the metabolic turnover of low clearance (CL) drugs because of their sustained metabolic capacity and longer-term viability. Erythromycin (ERY), a moderate, mechanism-based inhibitor of CYP3A, was evaluated as a tool in the HepatoPac model to assess contribution of CYP3A to the clearance of drug candidates. ERY inhibited CYP3A activity by 58% and 80% at 3 and 10 µM, respectively, for up to 72 hours. At 30 µM, ERY inhibited midazolam hydroxylation by >85% for the entire 144-hour duration of the incubation. Alprazolam CLint was inhibited 58% by 3 µM of ERY, 75% by 15 µM of ERY, 89% by 30 µM of ERY, and 94% by 60 µM of ERY. ERY (30 µM) did not markedly affect CLint of substrates for several other major cytochrome P450 isoforms evaluated and did not markedly inhibit uridine diphosphoglucuronosyl transferase (UGT) isoforms 1A1, 1A3, 1A4, 1A6, 1A9, 2B7, or 2B15 as assessed using recombinant UGTs. ERY only mildly increased CYP3A4 gene expression by 2.1-fold (14% of rifampicin induction) at 120 µM, indicating that at effective concentrations for inhibition of CYP3A activity (30-60 µM), arylhydrocarbon receptor, constitutive androstane receptor, and pregnane-X-receptor activation are not likely to markedly increase levels of other drug-metabolizing enzymes or transporters. ERY at concentrations up to 60 µM was not toxic for up to 6 days of incubation. Use of ERY to selectively inhibit CYP3A in high-functioning, long-term hepatocyte models such as HepatoPac can be a valuable strategy to evaluate the contribution of CYP3A metabolism to the overall clearance of slowly metabolized drug candidates. SIGNIFICANCE STATEMENT: This work describes the use of erythromycin as a selective inhibitor of CYP3A to assess the contribution of CYP3A in the metabolism of compounds using long-term hepatocyte cultures.

Evaluation of the Effects of Maytenus ilicifolia on the Activities of Cytochrome P450 3A and P-glycoprotein.

BACKGROUND: Maytenus ilicifolia is a Brazilian popular medicine commonly used to treat ulcer and gastritis. Despite the absence of toxicity regarding its consumption, possible interactions when co-administrated with conventional drugs, are unknown. OBJECTIVE: This study aimed to evaluate the effects of M. ilicifolia extracts on Cytochrome P450 3A (CYP3A) and P-glycoprotein (P-gp) activities. METHODS: The extracts were obtained by infusion (MI) or turbo-extraction using hydro-acetonic solvent (MT70). The content of polyphenols in each extract was determined. To assess the modulation of M. ilicifolia on P-gp activity, the uptake of fexofenadine (FEX) by Caco-2 cells was investigated in the absence or presence of MI or MT70. The effect on CYP3A activity was evaluated by the co-administration of midazolam (MDZ) with each extract in male Wistar rats. The pharmacokinetic parameters of the drug were determined and compared with those from the control group. The content of total phenolic compounds, tannins, and flavonoids on MT70 extract was about double of that found in MI. RESULTS: In the presence of the extracts, the uptake of the P-gp marker (FEX) by Caco-2 cells increased from 1.7 ± 0.4 ng.mg-1 protein (control) to 3.5 ± 0.2 ng.mg-1 protein (MI) and 4.4 ± 0.5 ng.mg-1 protein (MT70), respectively. When orally co-administrated with MDZ (substrate of CYP3A), the extracts augmented the AUC(0-∞) (Control: 911.7 ± 215.7 ng.h.mL-1; MI: 1947 ± 554.3 ng.h.mL-1; MT70: 2219.0 ± 506.3 ng.h.mL-1) and the Cmax (Control: 407.7 ± 90.4 ng.mL-1; MI: 1770.5 ± 764.5 ng.mL-1; MT70: 1987.2 ± 544.9 ng.mL-1) of the drug in rats indicating a 50% reduction of the oral Cl. No effect was observed when midazolam was given intravenously. CONCLUSION: The results suggest that M. ilicifolia can inhibit the intestinal metabolism and transport of drugs mediated by CYP3A and P-gp, respectively, however, the involvement of other transporters and the clinical relevance of such interaction still need to be clarified.

Evaluation of potential herbal-drug interactions of a standardized propolis extract (EPP-AF®) using an in vivo cocktail approach.

ETHNOPHARMACOLOGICAL RELEVANCE: Propolis has been employed extensively in many cultures since ancient times as antiseptic, wound healing, anti-pyretic and others due to its biological and pharmacological properties, such as immunomodulatory, antitumor, anti-inflammatory, antioxidant, antibacterial, antiviral, antifungal, antiparasite activities. But despite its broad and traditional use, there is little knowledge about its potential interaction with prescription drugs. AIM OF THE STUDY: The main objective of this work was to study the potential herbal-drug interactions (HDIs) of EPP-AF® using an in vivo assay with a cocktail approach. MATERIALS AND METHODS: Subtherapeutic doses of caffeine, losartan, omeprazole, metoprolol, midazolam and fexofenadine were used. Sixteen healthy adult volunteers were investigated before and after exposure to orally administered 125 mg/8 h (375 mg/day) EPP-AF® for 15 days. Pharmacokinetic parameters were calculated based on plasma concentration versus time (AUC) curves. RESULTS: After exposure to EPP-AF®, it was observed decrease in the AUC0-∞ of fexofenadine, caffeine and losartan of approximately 18% (62.20 × 51.00 h.ng/mL), 8% (1085 × 999 h.ng/mL) and 13% (9.01 × 7.86 h.ng/mL), respectively, with all 90% CIs within the equivalence range of 0.80-1.25. On the other hand, omeprazole and midazolam exhibited an increase in AUC0-∞ of, respectively, approximately 18% (18.90 × 22.30 h.ng/mL) and 14% (1.25 × 1.43 h.ng/mL), with the upper bounds of 90% CIs slightly above 1.25. Changes in pharmacokinetics of metoprolol or its metabolite α-hydroxymetoprolol were not statistically significant and their 90% CIs were within the equivalence range of 0.80-1.25. CONCLUSIONS: In conclusion, our study shows that EPP-AF® does not clinically change CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A activities, once, despite statistical significant, the magnitude of the changes in AUC values after EPP-AF® were all below 20% and therefore may be considered safe regarding potential interactions involving these enzymes. Besides, to the best of our knowledge this is the first study to assess potential HDIs with propolis.

Interaction of herbal products with prescribed medications: A systematic review and meta-analysis.

Although several studies on pharmacokinetic and/or pharmacodynamic herb-drug interactions (HDI) have been conducted in healthy volunteers, there is large uncertainty on the validity of these studies. A qualitative review and a meta-analysis were performed to establish the clinical evidence of these interaction studies. Out of 4026 screened abstracts, 32 studies were included into the qualitative analysis. The meta-analysis was performed on eleven additional studies. St. John's wort (SJW) significantly decreased the AUC (p < 0.0001) and clearance (p = 0.007) of midazolam. Further subgroup analysis identified age to affect Cmax of midazolam (p < 0.01) in the presence of SJW. Echinacea purpurea (EP) significantly increased the clearance of midazolam (p = 0.01). Evidence of publication bias (p > 0.001) was shown on the effect of the herbal products o half-life of midazolam. Green tea (GT) showed significant 85% decrease in plasma concentration of nadolol. The study findings suggest that GT, SJW and EP perpetuate significant interactions with prescribed medications via CYP3A4 or OATP1A2. Our studies show that meta-analyses are important in the area of natural products to provide necessary information on their use in overall medication plans in order to avoid unintended interactions.

Physiologically Based Pharmacokinetic Modelling of Hyperforin to Predict Drug Interactions with St John's Wort.

BACKGROUND AND OBJECTIVES: Herb-drug interactions with St John's wort (SJW) have been widely studied in numerous clinical studies. The objective of this study was to develop and evaluate a physiologically based pharmacokinetic (PBPK) model for hyperforin (the constituent of SJW responsible for interactions), which has the potential to provide unique insights into SJW interactions and allow prediction of the likely extent of interactions with SJW compared to published interaction reports. METHODS: A PBPK model of hyperforin accounting for the induction of cytochrome P450 (CYP) 3A, CYP2C9 and CYP2C19 was developed in the Simcyp® Simulator (version 17) and verified using published, clinically observed pharmacokinetic data. The predictive performance of this model based on the prediction fold-difference (expressed as the ratio of predicted and clinically observed change in systemic exposure of drug) was evaluated across a range of CYP substrates. RESULTS: The verified PBPK model predicted the change in victim drug exposure due to the induction by SJW (expressed as area under the plasma concentration-time curve (AUC) ratio) within 1.25-fold (0.80-1.25) of that reported in clinical studies. The PBPK simulation indicated that the unbound concentration of hyperforin in the liver was far lower than in the gut (enterocytes). Simulations revealed that induction of intestinal CYP enzymes by hyperforin was found to be more pronounced than the corresponding increase in liver CYP activity (15.5- vs. 1.1-fold, respectively, at a hyperforin dose of 45 mg/day). CONCLUSION: In the current study, a PBPK model for hyperforin was successfully developed, with a predictive capability for the interactions of SJW with different CYP3A, CYP2C9 and CYP2C19 substrates. This PBPK model is valuable to predict the extent of herb-drug interactions with SJW and help design the clinical interaction studies, particularly for new drugs and previously unstudied clinical scenarios.

A Comprehensive In Vivo and In Vitro Assessment of the Drug Interaction Potential of Red Ginseng.

Purpose: Red ginseng is one of the world's most popular herbal medicines; it exhibits a wide range of pharmacologic activities and is often co-ingested with other herbal and conventional medicines. This open-label, randomized, 3-period study investigated the in vivo herb-drug interaction potential for red ginseng extract with cytochrome P-450 (CYP) enzymes and organic anion-transporting polypeptide (OATP) 1B1. METHODS: Fifteen healthy male volunteers (22-28 years; 57.1-80.8 kg) were administered a single dose of cocktail probe substrates (caffeine 100 mg, losartan 50 mg, omeprazole 20 mg, dextromethorphan 30 mg, midazolam 2 mg, and pitavastatin 2 mg) and single or multiple doses of red ginseng extract for 15 days. FINDINGS: The pharmacokinetic profiles of the probe substrates and metabolites after single- or multiple-dose administration of red ginseng extracts were comparable to the corresponding profiles of the control group. The geometric mean ratio of AUC0-t and 90% CIs for the probe substrate drugs between the control and multiple doses of red ginseng for 15 days were within 0.8 to 1.25 (CYP2C9, CYP3A4, and OATP1B1 probe substrates) or slightly higher (CYP1A2, CYP2C19, and CYP2D6 probe substrates). Additional assessments of the in vitro drug interaction potential of red ginseng extracts and the ginsenoside Rb1 on drug-metabolizing enzymes and transporters using human liver microsomes, cryopreserved human hepatocytes, and transporter-overexpressed cells were negative. IMPLICATIONS: Red ginseng poses minimal risks for clinically relevant CYP- or OATP-mediated drug interactions and is well tolerated. Clinical Research Information Service registry no.

Effect of the active ingredient of Kaempferia parviflora, 5,7-dimethoxyflavone, on the pharmacokinetics of midazolam.

5,7-Dimethoxyflavone (5,7-DMF), one of the major components of Kaempferia parviflora, has anti-obesity, anti-inflammatory, and antineoplastic effects. On the other hand, in vitro studies have reported that it directly inhibits the drug metabolizing enzyme family cytochrome P450 (CYP) 3As. In this study, its safety was evaluated from a pharmacokinetic point of view, based on daily ingestion of 5,7-DMF. Midazolam, a substrate of CYP3As, was orally administered to mice treated with 5,7-DMF for 10 days, and its pharmacokinetic properties were investigated. In the group administered 5,7-DMF, the area under the curve (AUC) of midazolam increased by 130% and its biological half-life was extended by approximately 100 min compared to the control group. Compared to the control group, 5,7-DMF markedly decreased the expression of CYP3A11 and CYP3A25 in the liver. These results suggest that continued ingestion of 5,7-DMF decreases the expression of CYP3As in the liver, consequently increasing the blood concentrations of drugs metabolized by CYP3As.

Repeated administration of Sailuotong, a fixed combination of Panax ginseng, Ginkgo biloba, and Crocus sativus extracts for vascular dementia, alters CYP450 activities in rats.

BACKGROUND: Sailuotong (SLT) is a standard Chinese preparation made from extracts of Panax ginseng (ginseng), Ginkgo biloba (ginkgo), and Crocus sativus (saffron). Preliminary clinical trials and animal experiments have demonstrated that SLT could improve cognition of vascular dementia (VD). PURPOSE: To avoid incident drug-drug interaction which is easily encountered in patients of VD, the potential influence of SLT on main drug-metabolic cytochromes P450 enzymes (CYP450) was investigated. METHOD: A "cocktail probes" approach was employed to evaluate the activities of CYP450. A rapid and selective analysis method was developed to examine 5 CYP probe drugs and their specific metabolites in plasma by using online SPE followed by a single LC-MS/MS run. After pretreatment for 2 weeks with SLT, ginseng, gingko, saffron or water (control), a cocktail solution containing caffeine, losartan, omeprazole, dextromethorphan and midazolam was given to rats orally. The plasma was obtained at different time intervals and then measured for the concentration of probes and their metabolites using developed SPE-LC-MS/MS method. Activity of five isozymes was estimated by comparing plasma pharmacokinetics of substrates and their metabolites (caffeine/paraxanthine for CYP1A2, losartan/E-3174 for CYP2C11, omeprazole/5-hydroxyl omeprazole for CYP2C6, dextromethorphan/dextrophan for CYP2D2 and midazolam/1-hydroxyl midazolam for CYP3A1/2) between control and drug treatment groups. RESULT: Compared with control group, repeated administration of SLT induced CYP1A2 by enhancing AUC paraxanthine / AUC caffeine to144%. The influence is attributed to its herbal component of ginseng to a large extent. Meanwhile, metabolic ability towards losartan was significantly elevated in SLT and gingko group by 31% and 25% respectively, indicating weak induction of CYP2C11 in rats. The analysis on probes of omeprazole and dextromethorphan showed a lack of influence on CYP 2C6 and CYP2D2 in all treated groups. In terms of CYP3A1/2, SLT decreased AUC ratio of 1-hydroxyl midazolam to midazolam by 39% and extended the half-life of midazolam apparently. Besides, significantly decreased systematic exposure of midazolam suggested the inhibition on metabolism of CYP3A1/2 is likely secondary to the interaction on absorption at intestinal level. The inhibition of SLT on CYP3A was likely attributed to ginseng and gingko cooperatively. CONCLUSION: Further observation on herb-drug interaction should be considered during clinical application of SLT.

Effect of Benifuuki Tea on Cytochrome P450-mediated Metabolic Activity in Rats.

BACKGROUND/AIM: Benifuuki tea has recently been used as an alternative therapy for pollinosis, and it may be consumed with pharmaceutical drugs. This study aimed to examine cytochrome P450 (CYP)-mediated food-drug interactions with Benifuuki tea in rats. MATERIALS AND METHODS: The inhibitory effects of Benifuuki tea and (-)-epigallocatechin-3-O-(3-O-methyl) gallate (EGCG3"Me) on CYP activities were evaluated in vitro. Midazolam pharmacokinetics was investigated after two treatments with Benifuuki tea. In an ex vivo study, CYP activities were determined after 1-week-treatment with the tea. RESULTS: Benifuuki tea and EGCG3"Me inhibited CYP2D and CYP3A activities in a concentration-dependent manner in vitro. However, MDZ metabolism did not change by Benifuuki treatment in vivo and ex vivo. In contrast, CYP2D activity was decreased ex vivo. CONCLUSION: Normal intake of Benifuuki tea is not likely to cause food-drug interactions by CYP3A inhibition or induction. In contrast, Benifuuki tea consumption may lead to food-drug interactions through the inhibition of CYP2D.

Prediction of Clinically Relevant Herb-Drug Clearance Interactions Using Sandwich-Cultured Human Hepatocytes: Schisandra spp. Case Study.

The Schisandraceae family is reported to have a range of pharmacological activities, including anti-inflammatory effects. As with all herbal preparations, extracts of Schisandra species are mixtures composed of >50 lignans, especially schizandrins, deoxyschizandrins, and gomisins. In China, Schisandra sphenanthera extract (SSE) is often coadministered with immunosuppressant treatment of transplant recipients. In cases of coadministration, the potential for herb-drug interactions (HDIs) increases. Clinical studies have been used to assess HDI potential of SSE. Results demonstrated that chronic SSE administration reduced midazolam (MDZ) clearance by 52% in healthy volunteers. Although clinical studies are definitive and considered the "gold standard," these studies are impractical for routine HDI assessments. Alternatively, in vitro strategies can be used to reduce the need for clinical studies. Transporter-certified sandwich-cultured human hepatocytes (SCHHs) provide a fully integrated hepatic cell system that maintains drug clearance pathways (metabolism and transport) and key regulatory pathways constitutive active/androstane receptor and pregnane X receptor (CAR/PXR) necessary for quantitative assessment of HDI potential. Mechanistic studies conducted in SCHHs demonstrated that SSE and the more commonly used dietary supplement Schisandra chinensis extract (SCE) inhibited CYP3A4/5-mediated metabolism and induced CYP3A4 mRNA in a dose-dependent manner. SSE and SCE reduced MDZ clearance to 0.577- and 0.599-fold of solvent control, respectively, in chronically exposed SCHHs. These in vitro results agreed with SSE clinical findings and predicted a similar in vivo HDI effect with SCE exposure. These findings support the use of an SCHH system that maintains transport, metabolic, and regulatory functionality for routine HDI assessments to predict clinically relevant clearance interactions.

Effect of fermented red ginseng on cytochrome P450 and P-glycoprotein activity in healthy subjects, as evaluated using the cocktail approach.

AIMS: We assessed the drug interaction profile of fermented red ginseng with respect to the activity of major cytochrome (CYP) P450 enzymes and of a drug transporter protein, P-glycoprotein (P-gp), in healthy volunteers. METHODS: This study was an open-label crossover study. The CYP probe cocktail drugs caffeine, losartan, dextromethorphan, omeprazole, midazolam and fexofenadine were administered before and after 2 weeks of fermented red ginseng administration. Plasma samples were collected, and tolerability was assessed. Pharmacokinetic parameters were calculated, and the 90% confidence intervals (CIs) of the geometric mean ratios of the parameters were determined from logarithmically transformed data. Values were compared between before and after fermented red ginseng administration using analysis of variance (anova). RESULTS: Fifteen healthy male subjects were evaluated, none of whom were genetically defined as a poor CYP2C9, CYP2C19 or CYP2D6 metabolizer based on genotyping. Before and after fermented red ginseng administration, the geometric least-square mean metabolic ratio (90% CI) was 0.901 (0.830-0.979) for caffeine (CYP1A2) to paraxanthine, 0.774 (0.720-0.831) for losartan (CYP2C9) to EXP3174, 1.052 (0.925-1.197) for omeprazole (CYP2C19) to 5-hydroxyomeprazole, 1.150 (0.860-1.538) for dextromethorphan (CYP2D6) to dextrorphan, and 0.816 (0.673-0.990) for midazolam (CYP3A4) to 1-hydroxymidazolam. The geometric mean ratio of the area under the curve of the last sampling time (AUClast ) for fexofenadine (P-gp) was 1.322 (1.112-1.571). CONCLUSION: No significantly different drug interactions were observed between fermented red ginseng and the CYP probe substrates following the two-week administration of concentrated fermented red ginseng. However, the inhibition of P-gp was significantly different between fermented red ginseng and the CYP probe substrates. The use of fermented red ginseng requires close attention due to the potential for increased systemic exposure when it is used in combination with P-gp substrate drugs.