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GnRH antagonist

Cetrorelix

Published evidence · coverage incomplete
Anatomical contextAnatomy connections are not mapped yet.

No body region is highlighted until this profile has a supported anatomical connection. This does not mean the peptide has no biological effects.

Read published mechanism findings ↓

At a glance

What is it—and why does it matter?

Cetrorelix is described as a gonadotropin-releasing hormone (GnRH) antagonist with use in reproductive medicine. The hydrogel vehicle (chitosan 95/500 plus poloxamer 407) contains cetrorelix acetate dissolved rather than carrier-loaded. This study compared MPA with cetrorelix to prevent premature LH surge during ovarian stimulation in ART cycles (including ICSI and fertility preservation). The 0.25 mg Cetrotide presentation is a sterile lyophilized powder for subcutaneous injection after reconstitution using Sterile Water for Injection provided in a 1.0 mL pre-filled syringe.

Sources for this introduction: [1] [2] [3] [4]

This published profile is a reference in progress. Findings retain their source context; missing topics are marked below.

What is it?

A molecule, not a product name.

Identity

Cetrorelix is described as a gonadotropin-releasing hormone (GnRH) antagonist with use in reproductive medicine.

Sources[6]pubmedComparison of Chitosan-Poloxamer Nanoparticles and Poloxamer-based In-Situ Forming Gel for Nose-to-Brain Delivery of Cetrorelix: In Vitro and Pharmacokinetic Studies in Rats.cetrorelix, which is a GnRH antagonist used in reproductive medicine.
Source records
1
Independent studies
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “cetrorelix, which is a GnRH antagonist used in reproductive medicine.”

    Comparison of Chitosan-Poloxamer Nanoparticles and Poloxamer-based In-Situ Forming Gel for Nose-to-Brain Delivery of Cetrorelix: In Vitro and Pharmacokinetic Studies in Rats. · Abstract

    pubmed:42243608:d90288272a0b:d90288272a0b

How does it work?

Target, response, and disposition.

Mechanism

The hydrogel vehicle (chitosan 95/500 plus poloxamer 407) contains cetrorelix acetate dissolved rather than carrier-loaded.

Sources[3]pubmedHydrogel and oleogel formulation of the decapeptide cetrorelix acetate for nasal administration.In the hydrogel formulation consisting of chitosan 95/500 and poloxamer 407, CxAc was present in solubilised form.
Source records
1
Independent studies
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “In the hydrogel formulation consisting of chitosan 95/500 and poloxamer 407, CxAc was present in solubilised form.”

    Hydrogel and oleogel formulation of the decapeptide cetrorelix acetate for nasal administration. · Abstract

    pubmed:41722737:d06361c3a669:d06361c3a669

Mechanism

In HEK293 cells, cetrorelix blocked the human GnRH receptor with an IC50 of 4.2 nM.

Sources[1]chembl-activitiesChEMBL activities for CHEMBL1200490Assay: Antagonism of human GnHR receptor, determined in a reporter gene assay in HEK293 cells Assay format: cell-based format Standard result: IC50 = 4.2 nM
Reported result
IC50 = 4.2 nM
Source records
1
Independent studies
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “Assay: Antagonism of human GnHR receptor, determined in a reporter gene assay in HEK293 cells Assay format: cell-based format Standard result: IC50 = 4.2 nM”

    ChEMBL activities for CHEMBL1200490 · Activity 1290256

    chembl-activities:chembl1200490:bfb28f85c343:bfb28f85c343

Mechanism

The study developed cetrorelix-loaded Chi-Plx nanoparticles along with a Plx in-situ gel intended to extend nasal residence time.

Sources[6]pubmedComparison of Chitosan-Poloxamer Nanoparticles and Poloxamer-based In-Situ Forming Gel for Nose-to-Brain Delivery of Cetrorelix: In Vitro and Pharmacokinetic Studies in Rats.In this study, a cetrorelix-loaded chitosan-Pluronic F-127 (Chi-Plx) nanoparticle system with a complementary Plx in-situ gel to extend nasal residence time was developed.
Source records
1
Independent studies
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “In this study, a cetrorelix-loaded chitosan-Pluronic F-127 (Chi-Plx) nanoparticle system with a complementary Plx in-situ gel to extend nasal residence time was developed.”

    Comparison of Chitosan-Poloxamer Nanoparticles and Poloxamer-based In-Situ Forming Gel for Nose-to-Brain Delivery of Cetrorelix: In Vitro and Pharmacokinetic Studies in Rats. · Abstract

    pubmed:42243608:d90288272a0b:d90288272a0b

Pharmacokinetics

The cetrorelix-loaded Chi-Plx nanoparticle formulation had a nanoscale mean particle size of 18.7 ± 2.1 nm.

Sources[6]pubmedComparison of Chitosan-Poloxamer Nanoparticles and Poloxamer-based In-Situ Forming Gel for Nose-to-Brain Delivery of Cetrorelix: In Vitro and Pharmacokinetic Studies in Rats.Chi-Plx nanoparticles exhibited a mean diameter of 18.7 ± 2.1 nm
Reported result
18.7 ± 2.1 nm
Source records
1
Independent studies
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “Chi-Plx nanoparticles exhibited a mean diameter of 18.7 ± 2.1 nm”

    Comparison of Chitosan-Poloxamer Nanoparticles and Poloxamer-based In-Situ Forming Gel for Nose-to-Brain Delivery of Cetrorelix: In Vitro and Pharmacokinetic Studies in Rats. · Abstract

    pubmed:42243608:d90288272a0b:d90288272a0b

What has been studied?

What the evidence says.

Comparative evidence

This study compared MPA with cetrorelix to prevent premature LH surge during ovarian stimulation in ART cycles (including ICSI and fertility preservation).

Sources[5]pubmedMedroxyprogesterone acetate vs. GnRH antagonist for preventing premature LH surge during ovarian stimulation in assisted reproductive technology: a retrospective cohort study.To compare the effectiveness of medroxyprogesterone acetate (MPA) vs. cetrorelix (GnRH antagonist) in preventing premature LH surge during ovarian stimulation in assisted reproductive technology (ART) cycles, including cycles for intracytoplasmic sperm injection (ICSI) and fertility preservation.
Source records
1
Independent studies
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “To compare the effectiveness of medroxyprogesterone acetate (MPA) vs. cetrorelix (GnRH antagonist) in preventing premature LH surge during ovarian stimulation in assisted reproductive technology (ART) cycles, including cycles for intracytoplasmic sperm injection (ICSI) and fertility preservation.”

    Medroxyprogesterone acetate vs. GnRH antagonist for preventing premature LH surge during ovarian stimulation in assisted reproductive technology: a retrospective cohort study. · OBJECTIVE

    pubmed:41939000:afe2e88b6d24:afe2e88b6d24

Study findings

In Experiment 1, the dominant follicle was larger with cetrorelix than with estradiol benzoate on Day 8.

Sources[4]pubmedA new cetrorelix-based estrogen-free ovarian synchronization protocol for fixed-time artificial insemination in beef cattle.The dominant follicle was larger in the Cetrorelix than the Estradiol (P ≤ 0.03) on Day 8 (11.3 ± 0.4 vs 9.8 ± 0.3 mm)
Reported result
11.3 ± 0.4 vs 9.8 ± 0.3 mm (P ≤ 0.03)
Source records
1
Independent studies
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “The dominant follicle was larger in the Cetrorelix than the Estradiol (P ≤ 0.03) on Day 8 (11.3 ± 0.4 vs 9.8 ± 0.3 mm)”

    A new cetrorelix-based estrogen-free ovarian synchronization protocol for fixed-time artificial insemination in beef cattle. · Abstract

    pubmed:41864162:c17a6481d527:c17a6481d527

Study findings

Rheological testing in vitro showed thixotropy and non-Newtonian, condition-dependent viscosity (shear- and temperature-dependent) for both gel systems.

Sources[3]pubmedHydrogel and oleogel formulation of the decapeptide cetrorelix acetate for nasal administration.In vitro both gel formulations exhibited thixotropic behaviour as well as shear rate- and temperature-dependent viscosities.
Source records
1
Independent studies
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “In vitro both gel formulations exhibited thixotropic behaviour as well as shear rate- and temperature-dependent viscosities.”

    Hydrogel and oleogel formulation of the decapeptide cetrorelix acetate for nasal administration. · Abstract

    pubmed:41722737:d06361c3a669:d06361c3a669

Study findings

This difference is reported for heifers in Experiment 1 and includes a P value; it may not generalize beyond the described protocol and population.

Sources[4]pubmedA new cetrorelix-based estrogen-free ovarian synchronization protocol for fixed-time artificial insemination in beef cattle.In Experiment 1, new follicular wave emergence occurred earlier (P < 0.01) in the Cetrorelix group (2.4 ± 0.2 days) than the Estradiol group (3.8 ± 0.2 days).
Reported result
2.4 ± 0.2 days vs 3.8 ± 0.2 days (P < 0.01)
Source records
1
Independent studies
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “In Experiment 1, new follicular wave emergence occurred earlier (P < 0.01) in the Cetrorelix group (2.4 ± 0.2 days) than the Estradiol group (3.8 ± 0.2 days).”

    A new cetrorelix-based estrogen-free ovarian synchronization protocol for fixed-time artificial insemination in beef cattle. · Abstract

    pubmed:41864162:c17a6481d527:c17a6481d527

Risks and interactions

Risks, organized for scanning.

This profile does not yet contain a published summary for this topic. This is a coverage gap, not evidence that no research exists.

Products and regulatory status

Same ingredient. Different records.

Regulatory status

The labeled indication for cetrorelix acetate is inhibition of premature LH surges during controlled ovarian stimulation in women.

Sources[2]dailymedCetrotide®0.25 mg(cetrorelix acetate for injection)Cetrotide®(cetrorelix acetate for injection) is indicated for the inhibition of premature LH surges in women undergoing controlled ovarian stimulation.
Source records
1
Regulatory records
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “Cetrotide®(cetrorelix acetate for injection) is indicated for the inhibition of premature LH surges in women undergoing controlled ovarian stimulation.”

    Cetrotide®0.25 mg(cetrorelix acetate for injection) · INDICATIONS AND USAGE

    dailymed:aca7768e-28a7-4027-b1d8-e66247665f79:b5ef2c81068d:b5ef2c81068d

Administration context

The practical clinical context.

Administration

The 0.25 mg Cetrotide presentation is a sterile lyophilized powder for subcutaneous injection after reconstitution using Sterile Water for Injection provided in a 1.0 mL pre-filled syringe.

Sources[2]dailymedCetrotide®0.25 mg(cetrorelix acetate for injection)Cetrotide®(cetrorelix acetate for injection) 0.25 mg is a sterile lyophilized powder intended for subcutaneous injection after reconstitution with Sterile Water for Injection, that comes supplied in a 1.0 mL pre-filled syringe.
Source records
1
Regulatory records
1

Evidence boundary: Applies only to the source-defined population, formulation, dose, and assessment period.

Exact passages, locators, and provenance
  1. supports · Source-backed record
    “Cetrotide®(cetrorelix acetate for injection) 0.25 mg is a sterile lyophilized powder intended for subcutaneous injection after reconstitution with Sterile Water for Injection, that comes supplied in a 1.0 mL pre-filled syringe.”

    Cetrotide®0.25 mg(cetrorelix acetate for injection) · Cetrorelix acetate

    dailymed:aca7768e-28a7-4027-b1d8-e66247665f79:b5ef2c81068d:b5ef2c81068d

Research status + gaps

What still needs better answers?

  • No publishable claim yet for: contraindication, interaction, safety
  • 135 compiled claim(s) withheld by automated assurance: assurance_score_below_0.58 (98), assurance_score_below_0.72 (30), current_regulatory_source_required (18), extraction_ambiguity (118), high_risk_requires_regulatory_or_two_independent_sources (35), no_direct_support (123), proposal_not_staged (5)

These are the limits of this profile, not an exhaustive list of scientific uncertainties.

References + discovery

Open the records yourself.

  1. ChEMBL activities for CHEMBL1200490 ↗

    chembl-activities · published 2026-08-26 · retrieved 2026-08-26T08:42:26Z

  2. Cetrotide®0.25 mg(cetrorelix acetate for injection) ↗

    dailymed · published 2025-09-22 · retrieved 2026-09-04T19:14:18Z

  3. Hydrogel and oleogel formulation of the decapeptide cetrorelix acetate for nasal administration. ↗

    pubmed · published 2026-05-01 · retrieved 2026-08-26T08:42:26Z

  4. A new cetrorelix-based estrogen-free ovarian synchronization protocol for fixed-time artificial insemination in beef cattle. ↗

    pubmed · published 2026-07-15 · retrieved 2026-08-26T08:42:26Z

  5. Medroxyprogesterone acetate vs. GnRH antagonist for preventing premature LH surge during ovarian stimulation in assisted reproductive technology: a retrospective cohort study. ↗

    pubmed · published 2026-01-01 · retrieved 2026-08-26T08:42:26Z

  6. Comparison of Chitosan-Poloxamer Nanoparticles and Poloxamer-based In-Situ Forming Gel for Nose-to-Brain Delivery of Cetrorelix: In Vitro and Pharmacokinetic Studies in Rats. ↗

    pubmed · published 2026-06-04 · retrieved 2026-08-26T08:42:26Z

Publication history and provenance

Version 6 · Automated assessment · 2026-09-04T19:14:18Z

4f56c6df3ffb61f0f1c09943092d8d8e646c86830d78e12400d6b16eaa310549