Trial reportJournal of nuclear medicine : official publication, Society of Nuclear Medicine2009
A pilot study to assess the efficacy of tariquidar to inhibit P-glycoprotein at the human blood-brain barrier with (R)-11C-verapamil and PET.
Trial report in Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2009. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 60 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
60 citing papers in PubMed, 111 citations in OpenAlex.
- Effect of P-glycoprotein inhibition at the blood-brain barrier on brain distribution of (R)-[British journal of clinical pharmacology · 2017Trial
- Approaching complete inhibition of P-glycoprotein at the human blood-brain barrier: an (R)-[11C]verapamil PET study.Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism · 2015Trial
- Increased permeability-glycoprotein inhibition at the human blood-brain barrier can be safely achieved by performing PET during peak plasma concentrations of tariquidar.Journal of nuclear medicine : official publication, Society of Nuclear Medicine · 2015Trial
- Interaction of 11C-tariquidar and 11C-elacridar with P-glycoprotein and breast cancer resistance protein at the human blood-brain barrier.Journal of nuclear medicine : official publication, Society of Nuclear Medicine · 2013Trial
- Pharmacokinetics of single ascending doses of the P-glycoprotein inhibitor tariquidar in healthy subjects.Pharmacology · 2013Trial
- P-glycoprotein function at the blood-brain barrier: effects of age and gender.Molecular imaging and biology · 2012Trial
- A combined accelerator mass spectrometry-positron emission tomography human microdose study with 14C- and 11C-labelled verapamil.Clinical pharmacokinetics · 2011Trial
- Therapeutic Strategies to Overcome Payload Resistance of Trastuzumab Deruxtecan in HER2-Positive Cancers.Cancer science · 2026Article
- Measurement of cyclosporin induced changes in P-glycoprotein function at the human blood-brain barrier using [European journal of nuclear medicine and molecular imaging · 2025Article
- Designing a Small Molecule for PET Radiotracing: [Molecules (Basel, Switzerland) · 2025Review
- Enhanced plasma and brain concentrations and medulloblastoma cytotoxicity of asciminib and nilotinib by P-glycoprotein inhibition with tariquidar.Anti-cancer drugs · 2025Article
- Beyond the Walls of Troy: A Scoping Review on Pharmacological Strategies to Enhance Drug Delivery Across the Blood-Brain Barrier and Blood-Tumor Barrier.International journal of molecular sciences · 2025Article
- Do P-glycoprotein-mediated drug-drug interactions at the blood-brain barrier impact morphine brain distribution?Journal of pharmacokinetics and pharmacodynamics · 2025Article
- [Fluids and barriers of the CNS · 2024Article
- ATP-binding cassette transporter inhibitor potency and substrate drug affinity are critical determinants of successful drug delivery enhancement to the brain.Fluids and barriers of the CNS · 2024Article
- ABCB1 and ABCG2 Regulation at the Blood-Brain Barrier: Potential New Targets to Improve Brain Drug Delivery.Pharmacological reviews · 2023Review
- Transport Mechanisms at the Blood-Brain Barrier and in Cellular Compartments of the Neurovascular Unit: Focus on CNS Delivery of Small Molecule Drugs.Pharmaceutics · 2022Review
- Blood-brain barrier permeability following conventional photon radiotherapy - A systematic review and meta-analysis of clinical and preclinical studies.Clinical and translational radiation oncology · 2022Review
- P-Glycoprotein Inhibitor Tariquidar Plays an Important Regulatory Role in Pigmentation in Larval Zebrafish.Cells · 2021Article
- The Pharmacology of Xenobiotics after Intracerebro Spinal Fluid Administration: Implications for the Treatment of Brain Tumors.International journal of molecular sciences · 2021Review
Corrections and comments
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Authors and funding
11 authors at 3 institutions in 2 countries.
Funding
Abstract
unlabelledTariquidar, a potent, nontoxic, third-generation P-glycoprotein (P-gp) inhibitor, is a possible reversal agent for central nervous system drug resistance. In animal studies, tariquidar has been shown to increase the delivery of P-gp substrates into the brain by severalfold. The aim of this study was to measure P-gp function at the human blood-brain barrier (BBB) after tariquidar administration using PET and the model P-gp substrate (R)-(11)C-verapamil.
methodsFive healthy volunteers underwent paired (R)-(11)C-verapamil PET scans and arterial blood sampling before and at 2 h 50 min after intravenous administration of tariquidar (2 mg/kg of body weight). The inhibition of P-gp on CD56-positive peripheral lymphocytes of each volunteer was determined by means of the (123)Rh efflux assay. Tariquidar concentrations in venous plasma were quantified using liquid chromatography/mass spectrometry.
resultsTariquidar administration resulted in significant increases (Wilcoxon test for paired samples) in the distribution volume (DV, +24% +/- 15%) and influx rate constant (K(1), +49% +/- 36%) of (R)-(11)C-verapamil across the BBB (DV, 0.65 +/- 0.13 and 0.80 +/- 0.07, P = 0.043; K(1), 0.034 +/- 0.009 and 0.049 +/- 0.009, P = 0.043, before and after tariquidar administration, respectively). A strong correlation was observed between the change in brain DV after administration of tariquidar and tariquidar exposure in plasma (r = 0.90, P = 0.037). The mean plasma concentration of tariquidar achieved during the second PET scan (490 +/- 166 ng/mL) corresponded to 100% inhibition of P-gp function in peripheral lymphocytes.
conclusionTariquidar significantly increased brain penetration of (R)-(11)C-verapamil-derived activity due to increased influx. As opposed to peripheral P-gp function, central P-gp inhibition appeared to be far from complete after the administered tariquidar dose.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.