Assessing Pharmacokinetic Natural Product-Drug ... · Dietary Supplement Health and Education Act (DSHEA) •Passed by the United States Congress and signed into law by President

Assessing Pharmacokinetic Natural Product-Drug

Interactions: Challenges and Opportunities

Mary F. Paine, RPh, PhD

College of Pharmacy, Washington State University

June 14, 2018

Natural Products

Natural product umbrella

Food

Herbal products

Other botanicals

Vitamins

Minerals

Amino acids

All but food and non-tobacco botanicals are considered dietary supplements.

Dietary Supplement Health and Education Act (DSHEA)

• Passed by the United States Congress and signed into law by President

Bill Clinton in 1994.

• Dietary supplements can be marketed with general functional claims

but must be labeled appropriately.

• Dietary supplements must be proven unsafe before the Food and Drug

Administration can limit marketing.

“This claim has not been evaluated by the Food and Drug

Administration. This product is not intended to diagnose,

treat, cure or prevent any disease.”

Herbal product sales in the United States (1994-2016)

0

2

4

6

8

Billio

ns o

f D

olla

rs

Year

Adapted from Smith et al. (2017) HerbalGram

Clinical concerns with rising sales of herbal products

• Patients often seek herbal and other botanical natural products (NPs)

as a “natural” (therefore “safe”) means to alleviate illnesses or supple-

ment prescribed therapeutic regimens.

• Co-consuming NPs with conventional medications (prescription and

over-the-counter) can lead to adverse NP-drug interactions.

Paine et al. (2018) Drug Metab Dispos, in press

Mechanisms underlying NP-drug interactions

• Pharmacodynamic

◦ NP precipitates alteration(s) in the pharmacologic effect(s) of the object drug.

◦ Can be additive, synergistic, antagonistic, or a combination of these

• Pharmacokinetic

◦ NP precipitates alterations in the absorption, distribution, metabolism, or

excretion of the object drug.

◦ Inhibition or induction of drug metabolizing enzymes and/or transporters is

most common.

Challenges with NP-drug interaction predictions

• Compositional variability of NPs

◦ Seasonal changes, manufacturing variability

• Constitutional complexity of NPs

◦ Multiple bioactive constituents, isomers

• Scarce human pharmacokinetic data for NP constituents

• Lack of harmonized approaches


Center of Excellence for Natural Product-

Drug Interaction Research

Mission of the NaPDI Center

Provide leadership in the study of NP-drug interactions, with the

ultimate goal of developing a set of Recommended Approaches to

determine the clinical relevance of pharmacokinetic interactions

between NPs and conventional drugs.

NaPDI Center: Natural Product-Drug Interaction Research Center Paine et al. (2018) Drug Metab Dispos, in press

Objectives of the NaPDI Center

• Identify, prioritize, source, and characterize 4-6 NPs as potential

precipitants of clinically significant interactions with commonly used

medications. Pharmacology Core and Analytical Core

• Design in vitro and clinical studies for each NP that address existing

gaps in the scientific literature and definitively assess the clinical

relevance of any pharmacokinetic interaction. Pharmacology Core

• Develop and maintain a repository and public access portal for the data

and resources generated to facilitate improved design of future

research. Informatics Core

• Develop a set of Recommended Approaches to address the unique

challenges related to the study of NP-drug interactions. All Cores

NaPDI Center: Natural Product-Drug Interaction Research Center Paine et al. (2018) Drug Metab Dispos, in press

Anticipated Recommended Approaches


RA Short Description

1Selection of priority NPs for evaluation as potential precipitants of NP-drug

interactions Pharmacology Core

2Identification and characterization of optimal NP study materials for NP-drug

interactions Analytical Core

3Evaluation of a potential NP-drug interaction using static and dynamic

pharmacokinetic modeling of data obtained from in vitro systems and human

pharmacokinetic studies Pharmacology Core

4Design of “Phase 0” studies to understand NP constituent pharmacokinetics to

inform design of a clinical NP-drug interaction study Pharmacology Core

5Design of clinical NP-drug interaction studies using appropriate NP formulation,

object drug(s), and human subject group(s) Pharmacology Core

6Design and creation of a data repository and public portal of the NaPDI

Center’s NP-drug interaction data for access by researchers Informatics Core

RA, Recommended Approach

Anticipated Recommended Approaches


RA Short Description

1Selection of priority NPs for evaluation as potential precipitants of NP-drug

interactions Pharmacology Core

2Identification and characterization of optimal NP study materials for NP-drug

interactions Analytical Core

3Evaluation of a potential NP-drug interaction using static and dynamic

pharmacokinetic modeling of data obtained from in vitro systems and human

pharmacokinetic studies Pharmacology Core

4Design of “Phase 0” studies to understand NP constituent pharmacokinetics to

inform design of a clinical NP-drug interaction study Pharmacology Core

5Design of clinical NP-drug interaction studies using appropriate NP formulation,

object drug(s), and human subject group(s) Pharmacology Core

6Design and creation of a data repository and public portal of the NaPDI

Center’s NP-drug interaction data for access by researchers Informatics Core

RA, Recommended Approach

NP selection process

DIDB, Drug Interaction Database (UW)

target = drug metabolizing enzyme or transporter

47 NPs40 from

HerbalGram

7 from

DIDB

Johnson et al. (2018) Drug Metab Dispos, in press

Initial list of NP candidates (n=47)

Rank Natural Product Rank Natural Product Rank Natural Product

1 Horehound 17 Ginkgo 33 Fennel

2 Cranberry 18 Plant sterols 34 Horsetail

3 Echinacea 19 Red yeast rice 35 Tribulus

4 Black cohosh 20 Elderberry 36 White kidney bean

5 Flaxseed/flaxseed oil 21 Guarana 37 Evening primrose oil

6 Valerian 22 Coconut oil 38 Kelp

7 Yohimbe 23 Senna 39 Gymnema

8 Bioflavonoid complex 24 Ivy leaf 40 Grass

9 Saw palmetto 25 Chia seed/chia oil - Berberine

10 Ginger 26 Turmeric - Cannabinoids

11 Aloe vera 27 Maca - Feverfew

12 Milk thistle 28 Fenugreek - Glycyrrhizin

13 Garlic 29 Isoflavones - Goldenseal

14 Cinnamon 30 Ginseng - Shisandra spp.

15 Rhodiola 31 St. John’s wort - Resveratrol

16 Horny goat weed 32 Green tea




47 NPs40 from

HerbalGram

7 from

DIDB

In vivo interaction

documented in DIDB?

NO25

• High number of positive interactions,

• All interactions negative,

• Lack of in vitro targets, OR

• Negative:positive interactions ≥3:1

YES11

Gap analysis based on targets

and experimental systems

NO11 NPs

YES22 NPs

Positive: ≥20% change in object drug AUC

Negative: <20% change in object dug AUC


Gap analysis

Inhibition Induction Gaps

CYPs (1A2, 2B6, 2C8, 2C9, 2C19, 2D6, 3A4)

Recombinant enzymes Nonessential N/A

Human liver microsomes Essential N/A

Human hepatocytes Nonessential Essential

UGTs (2B7, 1A9, 1A1, 1A4, 1A6, 2B15, 1A3, 2B10, 1A8, 1A10)

Recombinant enzymes Nonessential N/A

Human liver microsomes Essential N/A

Human hepatocytes Essential Essential

Transporters (OATP1B1, OATP1B3, OATP2B1, OAT1, OAT3, OCT1, OCT2, P-gp, BCRP,

BSEP, NTCP, MRP2, MRP3, MATE1, MATE2K)

Transfected cell lines Essential N/A

Human hepatocytes Nonessential Essential

Nuclear receptors (PXR, CAR, AhR)

Human hepatocytes N/A Essential





47 NPs40 from

HerbalGram

7 from

DIDB

In vivo interaction

documented in DIDB?

NO25

• High number of positive interactions,

• All interactions negative,

• Lack of in vitro targets, OR

• Negative:positive interactions ≥3:1

YES11

Gap analysis based on targets

and experimental systems

Gaps weighed against existing

human in vitro and in vivo data

NO11 NPs

YES22 NPs

Positive: ≥20% change in object drug AUC

Negative: <20% change in object dug AUC


Final high priority NPs using the ‘fulcrum model’

Cannabinoids

Goldenseal

Green tea

Licorice

Turmeric

Johnson et al. (2018) Drug Metab Dispos, in pressNPDI, natural product-drug interaction

Green tea consumption patterns and uses

• Infusions of green tea leaves are among the most commonly consumed

beverages worldwide.

• Green tea supplements were ranked 4th in sales by HerbalGram in

September, 2017.

• Green tea products are promoted for cardioprotection, chemo-

prevention, and weight loss.

• Medicinal effects have been attributed to polyphenols known as

catechins, which constitute 30-42% of solid green tea.

Tian et al. (2018) Drug Metab Dispos

Major catechins in green tea

(-)-epicatechin (EC) (-)-gallocatechin (GC) (-)-epigallocatechin (EGC)

(-)-epigallocatechin-3-

O-gallate (EGCG)

(-)-epicatechin-3-O-

gallate (ECG)


Potential green tea-drug interaction targets

• Transporters

◦ Green tea constituents inhibited OATP1B1, OATP1B3, OCT1, OCT2, MATE1,

MATE2-K, and P-gp activity in transfected cell systems (IC50, 8-130 µM).

◦ Green tea (as a canned beverage) reduced systemic exposure (AUC and Cmax) to

nadolol by 85% in human subjects, which was attributed to inhibition of the

intestinal uptake transporter, OATP1A2 (existence questioned).

• Cytochromes P450 (CYPs)

◦ Well-studied both in vitro and in vivo

◦ No effects on the pharmacokinetics of probe substrates for CYP1A2 (caffeine),

CYP2C9 (losartan), CYP2D6 (dextromethorphan), and CYP3A4 (alprazolam,

buspirone) in human subjects

Maximum reported catechin concentrations in human plasma ≤4 μM Tian et al. (2018) Drug Metab Dispos

Potential green tea-drug interaction targets, cont’d

• Sulfotransferases

◦ A green tea extract (1.25 mg/mL) nearly abolished ritodrine sulfation in

recombinant SULT1A1 and SULT1A3 systems.

• UDP-glucuronosyltransferases (UGTs)

◦ IC50 for EGCG against UGT1A1, UGT1A4, UGT1A6, and UGT2B17 activity in

human liver microsomes or recombinant enzyme ranged from 17-400 µM.

◦ IC50 for EGCG against 4-methylumbelliferone (4-MU) glucuronidation in human

intestinal microsomes was 46 µM.

◦ EGCG at 100 µM inhibited 4-MU glucuronidation by 40-80% in UGT1A1-,

UGT1A8-, and UGT1A10-expressing cell lysates.

Intestinal UGTs were prioritized as targets for the green tea interaction project.

Maximum reported catechin concentrations in human plasma ≤4 μM Tian et al. (2018) Drug Metab Dispos

Hypothesis: green tea inhibits intestinal UGTs

Phase II metaboliteDrug Phase I metaboliteNatural product

LUMEN

PORTAL CIRCULATION

↑ in object

drug AUC

Green tea product selection for in vitro and clinical studies

• Steeped green tea was selected based on typical use and lack of need

for dissolution of bioactive constituents.

Product selection

Courtesy of Nadja B. Cech, PhD

Green tea product selection for in vitro and clinical studies

• Steeped green tea was selected based on typical use and lack of need

for dissolution of bioactive constituents.

• The Analytical Core used a state-of-the-art chemometrics approach to

select the green tea product for in vitro and clinical studies.

◦ A variety commercially available products – teas, powders, and supplements –

(n=45) were selected based on consumer sales and product quality reports.

◦ Reference materials from the NIST and a non-green tea were used as positive

and negative controls, respectively.

◦ Metabolomic data collection approaches were compared to characterize the

chemical composition of all green tea products.

◦ Green tea products that were most chemically similar to the NIST reference

material were selected for testing as inhibitors of intestinal UGT activity.

NIST, National Institute of Standards and Technology Kellogg et al. (2017) J Natr Prod

T001 T002 T003 T004 T005 T006 T007 T008 T009 T010 T011 T012 T013 T014 T015 T017 T018 T019 T020 T021 T022 T023 T024 T025 T026 T030 T031 T032 T033 T034 T035 T036 T039 T040 T042 T043 T044 T045

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T002 0.396 1.000 0.752 0.866 0.731 0.957 0.983 0.833 0.306 0.739 0.549 0.710 0.987 0.976 0.160 0.827 -0.406 0.862 -0.960 0.530 0.964 0.954 -0.110 0.728 -0.932 0.964 -0.293 -0.893 -1.000 -0.607 -0.542 -0.288 -0.608 -0.506 -0.722 -0.985 -0.959 0.755

T003 -0.251 0.752 1.000 0.977 0.999 0.852 0.799 0.301 -0.315 0.177 -0.087 0.096 0.712 0.719 0.764 0.263 -0.831 0.816 -0.537 -0.070 0.751 0.619 -0.176 0.691 -0.463 0.672 0.404 -0.381 -0.765 -0.966 -0.944 -0.828 -0.948 -0.913 -0.116 -0.631 -0.537 0.290

T004 -0.040 0.866 0.977 1.000 0.970 0.912 0.908 0.495 -0.109 0.381 0.126 0.303 0.843 0.817 0.611 0.456 -0.712 0.905 -0.693 0.142 0.874 0.772 -0.240 0.688 -0.628 0.814 0.206 -0.561 -0.875 -0.894 -0.856 -0.690 -0.874 -0.815 -0.323 -0.773 -0.694 0.407

T005 -0.283 0.731 0.999 0.970 1.000 0.840 0.778 0.269 -0.346 0.144 -0.120 0.063 0.688 0.701 0.785 0.231 -0.846 0.799 -0.510 -0.103 0.728 0.593 -0.165 0.689 -0.436 0.647 0.434 -0.351 -0.745 -0.973 -0.954 -0.846 -0.955 -0.925 -0.083 -0.606 -0.510 0.270

T006 0.131 0.957 0.852 0.912 0.840 1.000 0.925 0.647 0.028 0.519 0.299 0.497 0.903 0.975 0.380 0.655 -0.642 0.785 -0.859 0.269 0.875 0.828 0.070 0.876 -0.822 0.853 -0.064 -0.749 -0.961 -0.775 -0.726 -0.512 -0.789 -0.710 -0.510 -0.901 -0.855 0.742

T007 0.376 0.983 0.799 0.908 0.778 0.925 1.000 0.814 0.302 0.731 0.527 0.675 0.991 0.922 0.222 0.785 -0.399 0.941 -0.920 0.531 0.993 0.966 -0.280 0.630 -0.882 0.981 -0.223 -0.851 -0.984 -0.637 -0.572 -0.328 -0.620 -0.522 -0.690 -0.959 -0.923 0.623

T008 0.837 0.833 0.301 0.495 0.269 0.647 0.814 1.000 0.780 0.987 0.919 0.978 0.883 0.770 -0.385 0.992 0.166 0.701 -0.942 0.908 0.849 0.933 -0.265 0.339 -0.953 0.906 -0.744 -0.983 -0.823 -0.078 0.003 0.278 -0.070 0.053 -0.982 -0.913 -0.947 0.715

T009 0.992 0.306 -0.315 -0.109 -0.346 0.028 0.302 0.780 1.000 0.867 0.961 0.877 0.413 0.213 -0.827 0.767 0.746 0.260 -0.532 0.968 0.387 0.538 -0.381 -0.264 -0.578 0.481 -0.933 -0.677 -0.289 0.541 0.607 0.792 0.560 0.656 -0.871 -0.458 -0.541 0.344

T010 0.908 0.739 0.177 0.381 0.144 0.519 0.731 0.987 0.867 1.000 0.965 0.989 0.810 0.657 -0.494 0.972 0.316 0.644 -0.876 0.963 0.782 0.882 -0.346 0.185 -0.893 0.848 -0.806 -0.943 -0.727 0.061 0.142 0.405 0.076 0.197 -0.992 -0.838 -0.882 0.625

T011 0.985 0.549 -0.087 0.126 -0.120 0.299 0.527 0.919 0.961 0.965 1.000 0.976 0.631 0.475 -0.703 0.915 0.539 0.434 -0.745 0.993 0.592 0.728 -0.300 0.006 -0.781 0.680 -0.924 -0.854 -0.533 0.318 0.394 0.629 0.328 0.441 -0.973 -0.681 -0.751 0.558

T012 0.925 0.710 0.096 0.303 0.063 0.497 0.675 0.978 0.877 0.989 0.976 1.000 0.768 0.656 -0.569 0.981 0.346 0.545 -0.871 0.957 0.720 0.837 -0.214 0.221 -0.899 0.797 -0.867 -0.947 -0.696 0.126 0.205 0.468 0.127 0.248 -1.000 -0.820 -0.875 0.700

T013 0.490 0.987 0.712 0.843 0.688 0.903 0.991 0.883 0.413 0.810 0.631 0.768 1.000 0.929 0.090 0.862 -0.294 0.908 -0.962 0.628 0.990 0.989 -0.257 0.606 -0.935 0.994 -0.353 -0.914 -0.985 -0.534 -0.464 -0.204 -0.522 -0.415 -0.780 -0.986 -0.965 0.686

T014 0.319 0.976 0.719 0.817 0.701 0.975 0.922 0.770 0.213 0.657 0.475 0.656 0.929 1.000 0.167 0.790 -0.476 0.740 -0.939 0.432 0.882 0.876 0.110 0.848 -0.920 0.886 -0.279 -0.863 -0.975 -0.616 -0.556 -0.313 -0.638 -0.542 -0.665 -0.956 -0.934 0.856

T015 -0.805 0.160 0.764 0.611 0.785 0.380 0.222 -0.385 -0.827 -0.494 -0.703 -0.569 0.090 0.167 1.000 -0.419 -0.908 0.323 0.122 -0.677 0.154 -0.031 -0.013 0.423 0.201 0.039 0.897 0.300 -0.180 -0.879 -0.912 -0.986 -0.864 -0.914 0.552 0.011 0.125 -0.218

T017 0.833 0.827 0.263 0.456 0.231 0.655 0.785 0.992 0.767 0.972 0.915 0.981 0.862 0.790 -0.419 1.000 0.159 0.633 -0.949 0.888 0.811 0.905 -0.146 0.397 -0.967 0.875 -0.776 -0.991 -0.816 -0.056 0.024 0.299 -0.060 0.062 -0.983 -0.911 -0.951 0.789

T018 0.676 -0.406 -0.831 -0.712 -0.846 -0.642 -0.399 0.166 0.746 0.316 0.539 0.346 -0.294 -0.476 -0.908 0.159 1.000 -0.357 0.159 0.558 -0.304 -0.151 -0.282 -0.760 0.096 -0.213 -0.693 -0.026 0.422 0.945 0.962 0.963 0.964 0.984 -0.332 0.249 0.151 -0.194

T019 0.300 0.862 0.816 0.905 0.799 0.785 0.941 0.701 0.260 0.644 0.434 0.545 0.908 0.740 0.323 0.633 -0.357 1.000 -0.763 0.478 0.957 0.899 -0.562 0.398 -0.707 0.922 -0.067 -0.693 -0.867 -0.639 -0.583 -0.379 -0.592 -0.510 -0.565 -0.824 -0.771 0.324

T020 -0.619 -0.960 -0.537 -0.693 -0.510 -0.859 -0.920 -0.942 -0.532 -0.876 -0.745 -0.871 -0.962 -0.939 0.122 -0.949 0.159 -0.763 1.000 -0.715 -0.918 -0.961 0.081 -0.628 0.996 -0.951 0.549 0.983 0.954 0.363 0.288 0.013 0.371 0.254 0.878 0.993 1.000 -0.836

T021 0.981 0.530 -0.070 0.142 -0.103 0.269 0.531 0.908 0.968 0.963 0.993 0.957 0.628 0.432 -0.677 0.888 0.558 0.478 -0.715 1.000 0.605 0.732 -0.412 -0.068 -0.746 0.686 -0.888 -0.826 -0.516 0.313 0.388 0.617 0.335 0.446 -0.956 -0.659 -0.724 0.470

T022 0.452 0.964 0.751 0.874 0.728 0.875 0.993 0.849 0.387 0.782 0.592 0.720 0.990 0.882 0.154 0.811 -0.304 0.957 -0.918 0.605 1.000 0.982 -0.372 0.538 -0.882 0.993 -0.279 -0.865 -0.964 -0.566 -0.499 -0.250 -0.542 -0.440 -0.735 -0.953 -0.923 0.579

T023 0.603 0.954 0.619 0.772 0.593 0.828 0.966 0.933 0.538 0.882 0.728 0.837 0.989 0.876 -0.031 0.905 -0.151 0.899 -0.961 0.732 0.982 1.000 -0.342 0.492 -0.940 0.998 -0.454 -0.939 -0.950 -0.415 -0.340 -0.074 -0.397 -0.283 -0.849 -0.975 -0.966 0.652

T024 -0.308 -0.110 -0.176 -0.240 -0.165 0.070 -0.280 -0.265 -0.381 -0.346 -0.300 -0.214 -0.257 0.110 -0.013 -0.146 -0.282 -0.562 0.081 -0.412 -0.372 -0.342 1.000 0.528 0.041 -0.345 0.023 0.116 0.113 -0.006 -0.031 -0.073 -0.100 -0.127 0.229 0.124 0.101 0.469

T025 -0.145 0.728 0.691 0.688 0.689 0.876 0.630 0.339 -0.264 0.185 0.006 0.221 0.606 0.848 0.423 0.397 -0.760 0.398 -0.628 -0.068 0.538 0.492 0.528 1.000 -0.608 0.519 0.075 -0.501 -0.732 -0.731 -0.707 -0.567 -0.785 -0.740 -0.226 -0.656 -0.615 0.784

T026 -0.665 -0.932 -0.463 -0.628 -0.436 -0.822 -0.882 -0.953 -0.578 -0.893 -0.781 -0.899 -0.935 -0.920 0.201 -0.967 0.096 -0.707 0.996 -0.746 -0.882 -0.940 0.041 -0.608 1.000 -0.925 0.614 0.992 0.925 0.289 0.213 -0.063 0.302 0.184 0.904 0.979 0.995 -0.862

T030 0.547 0.964 0.672 0.814 0.647 0.853 0.981 0.906 0.481 0.848 0.680 0.797 0.994 0.886 0.039 0.875 -0.213 0.922 -0.951 0.686 0.993 0.998 -0.345 0.519 -0.925 1.000 -0.391 -0.917 -0.962 -0.475 -0.403 -0.142 -0.456 -0.346 -0.810 -0.973 -0.956 0.635

T031 -0.954 -0.293 0.404 0.206 0.434 -0.064 -0.223 -0.744 -0.933 -0.806 -0.924 -0.867 -0.353 -0.279 0.897 -0.776 -0.693 -0.067 0.549 -0.888 -0.279 -0.454 0.023 0.075 0.614 -0.391 1.000 0.691 0.274 -0.578 -0.639 -0.824 -0.562 -0.656 0.856 0.452 0.551 -0.558

T032 -0.753 -0.893 -0.381 -0.561 -0.351 -0.749 -0.851 -0.983 -0.677 -0.943 -0.854 -0.947 -0.914 -0.863 0.300 -0.991 -0.026 -0.693 0.983 -0.826 -0.865 -0.939 0.116 -0.501 0.992 -0.917 0.691 1.000 0.884 0.186 0.107 -0.172 0.192 0.070 0.951 0.957 0.984 -0.821

T033 -0.379 -1.000 -0.765 -0.875 -0.745 -0.961 -0.984 -0.823 -0.289 -0.727 -0.533 -0.696 -0.985 -0.975 -0.180 -0.816 0.422 -0.867 0.954 -0.516 -0.964 -0.950 0.113 -0.732 0.925 -0.962 0.274 0.884 1.000 0.623 0.558 0.307 0.623 0.522 0.708 0.982 0.953 -0.747

T034 0.475 -0.607 -0.966 -0.894 -0.973 -0.775 -0.637 -0.078 0.541 0.061 0.318 0.126 -0.534 -0.616 -0.879 -0.056 0.945 -0.639 0.363 0.313 -0.566 -0.415 -0.006 -0.731 0.289 -0.475 -0.578 0.186 0.623 1.000 0.997 0.936 0.995 0.988 -0.107 0.462 0.359 -0.225

T035 0.544 -0.542 -0.944 -0.856 -0.954 -0.726 -0.572 0.003 0.607 0.142 0.394 0.205 -0.464 -0.556 -0.912 0.024 0.962 -0.583 0.288 0.388 -0.499 -0.340 -0.031 -0.707 0.213 -0.403 -0.639 0.107 0.558 0.997 1.000 0.961 0.993 0.995 -0.187 0.389 0.284 -0.170

T036 0.751 -0.288 -0.828 -0.690 -0.846 -0.512 -0.328 0.278 0.792 0.405 0.629 0.468 -0.204 -0.313 -0.986 0.299 0.963 -0.379 0.013 0.617 -0.250 -0.074 -0.073 -0.567 -0.063 -0.142 -0.824 -0.172 0.307 0.936 0.961 1.000 0.931 0.967 -0.451 0.120 0.008 0.054

T039 0.486 -0.608 -0.948 -0.874 -0.955 -0.789 -0.620 -0.070 0.560 0.076 0.328 0.127 -0.522 -0.638 -0.864 -0.060 0.964 -0.592 0.371 0.335 -0.542 -0.397 -0.100 -0.785 0.302 -0.456 -0.562 0.192 0.623 0.995 0.993 0.931 1.000 0.992 -0.110 0.464 0.365 -0.284

T040 0.589 -0.506 -0.913 -0.815 -0.925 -0.710 -0.522 0.053 0.656 0.197 0.441 0.248 -0.415 -0.542 -0.914 0.062 0.984 -0.510 0.254 0.446 -0.440 -0.283 -0.127 -0.740 0.184 -0.346 -0.656 0.070 0.522 0.988 0.995 0.967 0.992 1.000 -0.232 0.352 0.249 -0.192

T042 -0.919 -0.722 -0.116 -0.323 -0.083 -0.510 -0.690 -0.982 -0.871 -0.992 -0.973 -1.000 -0.780 -0.665 0.552 -0.983 -0.332 -0.565 0.878 -0.956 -0.735 -0.849 0.229 -0.226 0.904 -0.810 0.856 0.951 0.708 -0.107 -0.187 -0.451 -0.110 -0.232 1.000 0.829 0.882 -0.696

T043 -0.544 -0.985 -0.631 -0.773 -0.606 -0.901 -0.959 -0.913 -0.458 -0.838 -0.681 -0.820 -0.986 -0.956 0.011 -0.911 0.249 -0.824 0.993 -0.659 -0.953 -0.975 0.124 -0.656 0.979 -0.973 0.452 0.957 0.982 0.462 0.389 0.120 0.464 0.352 0.829 1.000 0.993 -0.795

T044 -0.626 -0.959 -0.537 -0.694 -0.510 -0.855 -0.923 -0.947 -0.541 -0.882 -0.751 -0.875 -0.965 -0.934 0.125 -0.951 0.151 -0.771 1.000 -0.724 -0.923 -0.966 0.101 -0.615 0.995 -0.956 0.551 0.984 0.953 0.359 0.284 0.008 0.365 0.249 0.882 0.993 1.000 -0.825

T045 0.456 0.755 0.290 0.407 0.270 0.742 0.623 0.715 0.344 0.625 0.558 0.700 0.686 0.856 -0.218 0.789 -0.194 0.324 -0.836 0.470 0.579 0.652 0.469 0.784 -0.862 0.635 -0.558 -0.821 -0.747 -0.225 -0.170 0.054 -0.284 -0.192 -0.696 -0.795 -0.825 1.000

T030T001 0.547T002 0.964T003 0.672T004 0.814T005 0.647T006 0.853T007 0.981T008 0.906T009 0.481T010 0.848T011 0.680T012 0.797T013 0.994T014 0.886T015 0.039T017 0.875T018 -0.213T019 0.922T020 -0.951T021 0.686T022 0.993T023 0.998T024 -0.345T025 0.519T026 -0.925T030 1.000T031 -0.391T032 -0.917T033 -0.962T034 -0.475T035 -0.403T036 -0.142T039 -0.456T040 -0.346T042 -0.810T043 -0.973T044 -0.956T045 0.635 Kellogg et al. (2017) J Natr ProdT030 = NIST reference material

Redacted

Redacted Redacted

Redacted

Courtesy of Nadja B. Cech, PhD

Effects of green tea extracts/fractions on intestinal UGT activity

0

40

80

120

0 60 120 180

0

40

80

120

0 60 120 180

0

40

80

120

0 60 120 180

0

40

80

120

0 60 120 180

0

40

80

120

0 60 120 180

0

40

80

120

0 60 120 180P

erc

en

t C

on

tro

l Activity

Concentration (μg/mL)

T02

T13

NIST (T30)

T07

T22

NIST (T30-aq)

Extract

fx Afx B

fx Cfx D

fx E

UGT activity = 4-MU glucuronidation

Test system = human intestinal microsomes Tian et al. (2018) Drug Metab Dispos

Effects of major green tea catechins on intestinal UGT activity

All NP constituents were tested at 100 μM; nicardipine was tested at 400 μM.

Bars and error bars denote means ± SDs, respectively, of triplicate incubations.

Test system = human intestinal microsomes

0

40

80

120

Pe

rce

nt C

on

tro

l Activity

Catechins


IC50 for ECG and EGCG

Perc

ent

Contr

ol A

ctivity

EGCG (μM)

IC50, 58.7 ± 8.5 μM

ECG (μM)

IC50, 105 ± 10.7 μM

Concentration in cupa

of hot teab (μM)

EC 86.1 ± 29.1

ECG 104 ± 14.9

EGC 241 ± 38.9

EGCG 210 ± 37.3

GC 227 ± 38.2

a240 mLbPrepared from NIST leaf

reference material.


IC50 determined via nonlinear regression analysis using Phoenix WinNonlin

The data suggest a potentialinteraction between greentea and intestinal UGT drugsubstrates.


Raloxifene as a clinically relevant intestinal UGT substrate

• Selective estrogen receptor modulator indicated for osteoporosis and

breast cancer risk reduction

• Low oral bioavailability (<2%) due primarily to extensive intestinal

glucuronidation by UGT1As

• Inhibition of intestinal UGT1As could increase systemic exposure (AUC)

to raloxifene, leading to adverse effects (e.g., hot flashes, venous

thromboembolism).

Raloxifene

Raloxifene 4′-glucuronide (R4G)

Raloxifene 6-glucuronide (R6G)

UGT1A8

UGT1A10

UGT1A1

Raloxifene intestinal glucuronidation

UGT1A8 and UGT1A10 expressed in intestine but not liver

Ki for ECG and EGCG

InhibitorKi

R4G R6G

ECG (μM) 0.81 0.95

EGCG (μM) 1.99 2.02

Velocity vs. substrate concentration data

were described best by the simple

competitive inhibition model.

Ki’s were determined via nonlinear least-

squares regression analysis using

Phoenix WinNonlin (v6.4).


R4G, raloxifene-4’-glucuronide; R6G, raloxifene-6-glucuronide

0 2 4 6 8 1 0

0

4 0

8 0

1 2 0

0

0 .5 M

1 M

2 M

4 M

8 M

0 2 4 6 8 1 0

0

2 0 0

4 0 0

6 0 0

R4G formationECG

Raloxifene (μM)

Velo

city (

pm

ol/m

in/m

g p

rote

in

0 2 4 6 8 1 0

0

2 0 0

4 0 0

6 0 0

8 0 0

0 2 4 6 8 1 0

0

5 0

1 0 0

1 5 0

0

1 M

2 M

4 M

8 M

1 6 M

R6G formation

EGCG

The Ki’s for ECG and EGCG were100x lower than concentrationsmeasured in a cup of hot teaprepared from the NIST product.


In vitro-in vivo prediction

Ig, inhibitor concentration in gut

Fg, fraction of oral drug dose that escapes gut extraction (literature: 0.054)

fu,g, unbound fraction of inhibitor in gut (~1)b

Ki, experimentally determined using HIM (1 or 2 μM)

fu,mic, unbound fraction of inhibitor in HIM (~1)b

Fa, fraction of inhibitor dose absorbed into enterocytes (~0.65)b

ka, first-order absorption rate constant (default: 0.1 min-1)

Qent, blood flow through enterocytes (literature: 248 ml/min)

i

g g

g u,g

i u,mic

AUC 1 =

1AUC1-F × + F

I × f1+

K × f

Inhibitor Ig (μM)Predicted

AUCi / AUC

ECG

Gut lumen concentrationa 4.4 4.4

Enterocyte concentrationb 0.18 1.2

EGCG

Gut lumen concentrationa 15.2 6.1

Enterocyte concentrationb 0.54 1.3

aCalculated according to Fa x ka x Dose/QentbSimulated using Simcyp


Clinical study design and procedures

• Healthy volunteers (8 men, 8 women)

◦ Sample size was based on 80% power to detect a 25% change in the primary

endpoint with a Type I error of 0.05.

◦ Primary endpoint: log-transformed raloxifene AUC ratio (green tea/baseline)

• Raloxifene (60 mg po) was administered alone (baseline), with green

tea on 1 day (acute), or upon a 5-day treatment with green tea (chronic)

in a fixed-sequence fashion.

• Plasma and urine were collected from 0-96 and 0-24 h, respectively.

• The pre-defined no effect range was 0.75-1.33.

Phase I(baseline)

≥1 week washout

Phase II(acute

green tea)

≥1 week washout

Phase III

(chronic

green tea)

McCune et al. (2018) Clin Pharmacol Ther Suppl S1

Slides 36-42 redacted

Summary and conclusion

• Green tea, one of four NPs selected to study as a precipitant of NP-drug

interactions, was the first to be advanced to an interaction project.

• Based on a gap analysis, intestinal UGTs were prioritized as targets for

the in vitro and clinical green tea-drug interaction studies.

• A pharmacokinetic interaction occurred between a well-characterized

green tea and the intestinal UGT substrate raloxifene, as the geometric

mean raloxifene AUC lay below the pre-defined no effect range.

• The greater decrease in raloxifene geometric mean Cmax relative to AUC,

combined with a minimal change in terminal half-life, suggested that

green tea alters primarily processes in the intestine, which could

include permeability, transport, and/or physicochemical processes

involved in raloxifene absorption.

Slides 44-48 redacted

Acknowledgements

Craig Hopp, PhD; U54 AT008909

Joe Zolnerciks, PhD

Chris Black, PhD

Ken Brouwer, RPh, PhD

Jonathan Jackson, PhD

Dandan Tian, PhD (Pharmacology Core, WSU)

Deena Hadi, BS (Administrative Core, WSU)

John White, PharmD, PA-C (Pharmacology Core, WSU)

Matt Layton, MD, PhD (Pharmacology Core, WSU)

Diana Forrest & Paul Hardy, PharmD candidates (WSU)

Danny Shen, PhD (Admin. Core, former co-PI, UW)

Ken Thummel, PhD (Analytical Core, UW)

Allan Rettie, PhD (Pharmacology Core, UW)

Jash Unadkat, PhD (Pharmacology Core, UW)

Nicholas Oberlies, PhD (Analytical Core, UNCG)

Nadja Cech, PhD (Analytical Core, UNCG)

Josh Kellogg, PhD (Analytical Core, UNCG)

Jeannine McCune, PharmD (Admin. Core, former co-PI, COH)

Richard Boyce, PhD (Informatics Core, Pitt)

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