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Study · Non-randomized trial · n = 3 · 1988

11 results

Absorption and metabolism of nafarelin, a potent agonist of gonadotropin-releasing hormone.

Chan RL, Henzl MR, LePage ME, LaFargue J, Nerenberg CA, Anik S, Chaplin MD

Clinical pharmacology and therapeutics1 Sept 1988Cited by 17 (Europe PMC)

PMID2970910 (opens in a new tab)DOI10.1038/clpt.1988.150 (opens in a new tab)PepBankPUB-02970910
Publisher pagePubMedAsk about this study
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Summary

The text of this summary is not shown here, because the article license does not allow reuse. Read it at the source (opens in a new tab)

Text rights: Publisher copyright. Results still quote short attributed sentences.

Results from this study11

9 results from studies that gave the peptide. 9 results from people.

  1. 01HumanNon-randomized trialPharmacokinetics

    In people given radiolabeled nafarelin, radioactivity was excreted in approximately equal amounts in urine and stool.

    In plain wordsIn people, roughly equal amounts of radioactivity from labeled nafarelin left through urine and stool.

    Peptide
    Nafarelin
    Outcome
    Not applicableUrinary and fecal excretion
    Study

    n = 3

    Outcome group
    Pharmacokinetics · Pharmacology
    Studied dose
    Dose not stated · subcutaneousAs given in this study (human).

    Source sentences

    Summary
    Radioactivity was excreted in approximately equal amounts in urine and stool.
    1 context sentence
    Summary · context
    The metabolism and excretion of nafarelin were determined in three subjects after subcutaneous administration of [14C]-nafarelin.
  2. 02HumanNon-randomized trialPharmacokinetics

    In people given radiolabeled nafarelin, six metabolites accounted for most urinary radioactivity.

    In plain wordsIn people, six breakdown products explained most urinary radioactivity after labeled nafarelin.

    Peptide
    Nafarelin
    Outcome
    Not applicableUrinary metabolites
    Study

    n = 3

    Outcome group
    Pharmacokinetics · Pharmacology
    Studied dose
    Dose not stated · subcutaneousAs given in this study (human).

    Measurements

    Metabolites accounting for most urinary radioactivity
    6 metabolites
    urine after subcutaneous [14C]-nafarelin

    Source sentences

    Summary
    Six metabolites accounted for most of the radioactivity in urine.
    1 context sentence
    Summary · context
    The metabolism and excretion of nafarelin were determined in three subjects after subcutaneous administration of [14C]-nafarelin.
  3. 03HumanNon-randomized trialPharmacokinetics

    In people, nafarelin metabolites included four short peptide fragments, naphthylalanine, and 2-naphthylacetic acid.

    In plain wordsIn people, nafarelin formed four peptide fragments and the breakdown products naphthylalanine and 2-naphthylacetic acid.

    Peptide
    Nafarelin
    Outcome
    Not applicableMetabolite identity
    Study

    n = 3

    Outcome group
    Pharmacokinetics · Pharmacology
    Studied dose
    Dose not stated · subcutaneousAs given in this study (human).

    Measurements

    Urinary metabolites that were short peptide fragments of nafarelin
    4 metabolites
    urine after subcutaneous [14C]-nafarelin

    Source sentences

    Summary
    Four metabolites were short peptide fragments of nafarelin and the other metabolites were naphthylalanine and 2-naphthylacetic acid.
    1 context sentence
    Summary · context
    The metabolism and excretion of nafarelin were determined in three subjects after subcutaneous administration of [14C]-nafarelin.
  4. 04HumanNon-randomized trialPharmacokinetics

    In people, intranasal nafarelin reached peak systemic concentration in 20 to 40 minutes.

    In plain wordsIn people, nafarelin nasal dosing produced peak blood levels in 20 to 40 minutes.

    Peptide
    Nafarelin
    Outcome
    Not applicableIntranasal absorption
    Study

    n: not reported in source

    Outcome group
    Pharmacokinetics · Pharmacology
    Studied dose
    Dose not stated · intranasalAs given in this study (human).

    Measurements

    Time to peak concentration
    20 to 40 minutes
    intranasal administration

    Source sentences

    Summary
    Nafarelin, a potent gonadotropin-releasing hormone (GnRH) agonist, was absorbed rapidly into systemic circulation (time to reach peak concentration, 20 to 40 minutes) after intranasal but not after sublingual or vaginal administration.
  5. 05HumanNon-randomized trialPharmacokinetics

    In people, rapid systemic absorption of nafarelin was not observed after sublingual administration.

    In plain wordsIn people, nafarelin did not enter the blood rapidly after dosing under the tongue.

    Peptide
    Nafarelin
    Outcome
    Direction not reportedSublingual absorption
    Study

    n: not reported in source

    Outcome group
    Pharmacokinetics · Pharmacology
    Studied dose
    Dose not stated · sublingualAs given in this study (human).

    Source sentences

    Summary
    Nafarelin, a potent gonadotropin-releasing hormone (GnRH) agonist, was absorbed rapidly into systemic circulation (time to reach peak concentration, 20 to 40 minutes) after intranasal but not after sublingual or vaginal administration.
  6. 06HumanNon-randomized trialPharmacokinetics

    In people, rapid systemic absorption of nafarelin was not observed after vaginal administration.

    In plain wordsIn people, nafarelin did not enter the blood rapidly after vaginal dosing.

    Peptide
    Nafarelin
    Outcome
    Direction not reportedVaginal absorption
    Study

    n: not reported in source

    Outcome group
    Pharmacokinetics · Pharmacology
    Studied dose
    Dose not stated · vaginalAs given in this study (human).

    Source sentences

    Summary
    Nafarelin, a potent gonadotropin-releasing hormone (GnRH) agonist, was absorbed rapidly into systemic circulation (time to reach peak concentration, 20 to 40 minutes) after intranasal but not after sublingual or vaginal administration.
  7. 07HumanNon-randomized trialPharmacokinetics

    In people given nafarelin, serum elimination half-life was about 2 hours.

    In plain wordsIn people, nafarelin blood levels fell by half in about 2 hours.

    Peptide
    Nafarelin
    Outcome
    Not applicableElimination half-life
    Study

    n: not reported in source

    Outcome group
    Pharmacokinetics · Pharmacology
    Studied dose
    Dose not stated

    Measurements

    Serum elimination half-life
    ≈ 2 hours
    nafarelin

    Source sentences

    Summary
    Serum elimination half-life was about 2 hours.
  8. 08HumanNon-randomized trialPharmacokinetics

    In people, increasing nafarelin concentration in the nasal formulation increased absorption.

    In plain wordsIn people, a more concentrated nafarelin nasal formulation increased absorption.

    Peptide
    Nafarelin
    Outcome
    IncreaseConcentration and nasal absorption
    Study

    n: not reported in source

    Outcome group
    Pharmacokinetics · Pharmacology
    Studied dose
    Dose not stated · intranasalAs given in this study (human).

    Source sentences

    Summary
    Nasal absorption of nafarelin was increased by increasing the concentration of the drug in the dose solution and incorporating sodium glycocholate into the nasal formulation.
  9. 09HumanNon-randomized trialPharmacokinetics

    In people, bioavailability of the optimized nafarelin nasal formulation averaged 21% relative to a single subcutaneous dose.

    In plain wordsIn people, the nafarelin nasal formulation had 21% bioavailability compared with a single injection under the skin.

    Peptide
    Nafarelin
    Outcome
    Not applicableNasal bioavailability
    Study

    n: not reported in source

    Comparator
    Single subcutaneous dose
    Outcome group
    Pharmacokinetics · Pharmacology
    Studied dose
    1.75 mg nafarelin per ml · intranasalAs given in this study (human).

    Measurements

    Mean bioavailability relative to subcutaneous dose
    21%
    optimal intranasal formulation, 1.75 mg nafarelin per ml with 2% sodium glycocholate

    Source sentences

    Summary
    Bioavailability of this nasal formulation relative to a single subcutaneous dose averaged 21%.
    1 context sentence
    Summary · context
    An optimal formulation providing maximum nasal absorption of nafarelin was one containing 1.75 mg nafarelin per ml and 2% sodium glycocholate.

Studies that did not test the peptide alone2

In this study, Nafarelin was a lab tool or a carrier, part of a mix, or the subject of a lab method. These results are not evidence about taking Nafarelin.

  1. 10HumanNot a test of Nafarelin aloneNon-randomized trialPharmacokinetics

    In people, adding sodium glycocholate to the nafarelin nasal formulation increased absorption.

    In plain wordsIn people, sodium glycocholate increased absorption from the nafarelin nasal formulation.

    Peptide
    Nafarelin
    Outcome
    IncreaseGlycocholate and nasal absorption
    Study

    n: not reported in source

    Outcome group
    Pharmacokinetics · Pharmacology

    Source sentences

    Summary
    Nasal absorption of nafarelin was increased by increasing the concentration of the drug in the dose solution and incorporating sodium glycocholate into the nasal formulation.

    In this study, Nafarelin was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking Nafarelin.

  2. 11HumanNot a test of Nafarelin aloneNon-randomized trialPharmacokinetics

    In people, maximum nasal absorption occurred with a formulation containing 1.75 mg/ml nafarelin and 2% sodium glycocholate.

    In plain wordsIn people, the best nasal absorption used 1.75 mg/ml nafarelin with 2% sodium glycocholate.

    Peptide
    Nafarelin
    Outcome
    Not applicableOptimal nasal formulation
    Study

    n: not reported in source

    Outcome group
    Pharmacokinetics · Pharmacology

    Source sentences

    Summary
    An optimal formulation providing maximum nasal absorption of nafarelin was one containing 1.75 mg nafarelin per ml and 2% sodium glycocholate.

    In this study, Nafarelin was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking Nafarelin.

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

Version history

PepBank keeps every version of the data on this study. Status changes from Retraction Watch, Europe PMC and Crossref are listed with their source.

  1. Version 2Current

    28 Oct 2026, 02:03 UTC

    Study results updated

  2. Version 1

    27 Oct 2026, 16:36 UTC

    First added · source update from Europe PMC

Subjects

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