Ganirelix Acetate | CAS 123246-29-7 | GnRH Receptor Antagonist (Research Use Only) | Knowlux

Product Description

Ganirelix Acetate, CAS 123246-29-7, is a synthetic decapeptide gonadotropin-releasing hormone (GnRH) receptor antagonist supplied by Knowlux for laboratory research use. The peptide is derived from native GnRH through substitutions at positions 1, 2, 3, 6, 8, and 10, yielding the sequence Ac-D-2-Nal-D-Phe(4-Cl)-D-3-Pal-Ser-Tyr-D-Har(Et2)-Leu-Har(Et2)-Pro-D-Ala-NH2. The molecular formula and molecular weight are salt-form dependent and are addressed in the CAS and Salt Form Clarification below. Each lot is released with a lot-specific COA, MSDS and analytical traceability.

CAS and Salt Form Clarification: CAS 123246-29-7 is the identifier most widely applied to Ganirelix Acetate across ChemicalBook, AbMole, Selleck, and DailyMed, but the molecular formula and molecular weight associated with this CAS diverge across sources in a manner that requires explicit clarification. The free peptide (net Ganirelix) corresponds to formula C80H113ClN18O13 with a molecular weight of 1570.34. The DailyMed prescribing information states the molecular weight "for Ganirelix Acetate is 1570.4 as an anhydrous free base," which confirms that 1570.34 is the net peptide value rather than the acetate salt value. The acetate salt, however, is represented with differing stoichiometries: Selleck lists C80H113ClN18O13.2C2H4O2 with MW 1690.43 (diacetate), while TargetMol and Aobious list C82H117ClN18O15 with MW 1630.4 (monoacetate), and the ChemicalBook Chinese product page reports a molecular weight of 1690.42 for the diacetate with the formula C80H113N18O13Cl.2CH3COOH. Knowlux specifies the salt stoichiometry, acetate content, and water content per lot on the COA. Buyers should confirm whether the quoted material is reported on a free-peptide, monoacetate, or diacetate basis before procurement, as the counter-ion load shifts the mass balance by approximately 60 g/mol per acetate.

Structural Note: The decapeptide backbone incorporates several non-natural residues that distinguish Ganirelix from native GnRH: D-2-naphthylalanine at position 1, D-4-chlorophenylalanine at position 2, D-3-pyridylalanine at position 3, and N9,N10-diethyl-D/L-homoarginine at positions 6 and 8. The N-terminus is acetylated and the C-terminus is D-alaninamide (D-Ala-NH2). Unlike the disulfide-constrained peptides in the Plecanatide and Ziconotide families, Ganirelix is linear and contains no cysteine residues, which simplifies handling with respect to reducing agents.

Product Parameters

Product Details

1. Overview

Ganirelix is a third-generation synthetic decapeptide that acts as a competitive antagonist at the pituitary GnRH receptor. Unlike GnRH agonists, which produce an initial stimulatory flare before receptor desensitization, Ganirelix binds the receptor without activating it, producing immediate and reversible suppression of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion. The suppression of LH is more pronounced than that of FSH, and an initial gonadotropin release has not been detected with Ganirelix, consistent with a pure antagonist mechanism. Upon discontinuation, pituitary LH and FSH levels recover fully within approximately 48 hours. In clinical medicine, Ganirelix Acetate is approved for the prevention of premature LH surges in women undergoing controlled ovarian stimulation as part of assisted reproductive technology. The material supplied under this specification is research-grade and is not intended for human administration. Knowlux supplies this compound strictly for laboratory investigation of GnRH receptor pharmacology, pituitary hormone regulation, and reproductive endocrinology.

2. Receptor Pharmacology and Selectivity

Ganirelix binds the human GnRH receptor with high affinity. BenchChem reports a dissociation constant (Kd) of 0.4 nM and an IC50 of 3.6 nM at the human GnRH receptor, compared with a Kd of 3.6 nM for native GnRH at the same receptor. The approximately 9-fold higher binding affinity of Ganirelix relative to the endogenous ligand is the quantitative basis for its antagonist potency. Functional antagonism is further characterized by a pA2 of 9.3, reported by Biorbyt and Bertin Bioreagent for the acetate salt. The GnRH receptor is a class A GPCR that couples primarily to Gq/11; antagonist binding blocks phospholipase C activation and the downstream mobilization of intracellular calcium that would otherwise drive gonadotropin synthesis and release. An additional pharmacological property relevant to in vitro systems is histamine release: Ganirelix induces a concentration-dependent increase in histamine release from rat peritoneal mast cells in vitro with an EC50 of approximately 11 microg/mL, a liability shared with Abarelix but not with all later-generation GnRH antagonists. Researchers designing assays in mast cell or histamine-sensitive systems should account for this off-target activity. These values are assay- and system-dependent and are provided for scientific reference only.

3. Research Applications

Published pharmacological characterizations and documented protocols describe the following research applications:

• GnRH receptor binding and functional antagonist assays (radioligand displacement, reporter gene antagonism)

• Pituitary LH and FSH secretion suppression studies in gonadotroph cell models

• Controlled ovarian stimulation and reproductive endocrinology research models

• Comparative pharmacology of GnRH antagonists (Ganirelix versus cetrorelix and abarelix)

• Histamine release and mast cell activation studies (Ganirelix as a positive control for pseudoallergic mechanisms)

• Reference standard development for HPLC and LC-MS analytical methods

These descriptions are derived from published research and are provided for scientific reference only. They do not constitute clinical guidance or dosing recommendations.

Quality Control

Solubility and Handling

Solubility: Ganirelix Acetate solubility is salt-form- and condition-dependent, and supplier data span a wider range than for most peptides in this catalogue. Selleck's batch-tested experimental data for its acetate salt reports DMSO solubility of 100 mg/mL (59.15 mM), water solubility of 100 mg/mL, and ethanol solubility of 100 mg/mL. MedChemExpress reports H2O solubility of 50 mg/mL (29.58 mM, with sonication) and PBS (pH 7.2) solubility of 50 mg/mL (29.58 mM, clear solution with sonication) for its Ganirelix acetate lot. Biorbyt and ProbeChem both list DMSO solubility of 10 mM, which is substantially lower than Selleck's 100 mg/mL figure and likely reflects a different salt form, a different lot, or a different dissolution protocol. The EMA assessment report notes that Ganirelix is highly soluble under aqueous physiological pH, which is consistent with the high water solubility values reported by Selleck and MedChemExpress. For practical stock preparation, water or PBS at up to 50 mg/mL is supported by MedChemExpress batch data, and DMSO at 10 mM is a conservative starting point if a lower-solubility lot is encountered. Selleck's guidance notes that DMSO stock precipitation in aqueous media can be mitigated by preheating the media to 37C and mixing rapidly upon addition. Prepare solutions fresh and aliquot to avoid repeated freeze-thaw cycles.

Handling Precautions: Use powder-handling containment (glove box or fume hood with particulate control). Avoid inhalation of fine powder. Wear nitrile gloves, lab coat, and eye protection. The histamine-releasing property documented in the pharmacological literature warrants awareness when handling the compound in settings involving mast cells or histamine-sensitive assays. Follow institutional chemical hygiene plans for research peptides.

Storage and Stability

Documentation Support

Per lot: COA, MSDS, certificate of origin, HPLC chromatogram, and mass spectrometry data. Acetate content, water content, peptide content, and counter-ion stoichiometry available on request. Custom specifications and third-party inspection can be arranged on a project basis.

About Knowlux

Knowlux Biotechnology is a GMP-oriented manufacturer and supplier of peptides, APIs and fine-chemical research compounds, operating from Hubei, China. We serve research groups, CDMOs and distributors in more than 40 countries, and support contract synthesis, custom packaging and technical documentation requests.

Compliance Statement

FOR RESEARCH USE ONLY. NOT FOR HUMAN USE. NOT FOR DIAGNOSTIC OR THERAPEUTIC USE.

This product is supplied for laboratory research use only. It is not for human or animal administration, not for diagnostic or therapeutic use, not for retail sale, and not for personal use. Ganirelix Acetate is an approved medicinal product in certain jurisdictions for specific clinical indications (prevention of premature LH surges in assisted reproductive technology); however, the material offered under this specification is research-grade and is not intended for clinical use. The purchaser is responsible for verifying product specifications against their specific research requirements and for compliance with all applicable institutional, local, and national regulations governing research chemical acquisition, storage, and use. Research context statements are for scientific reference only and do not constitute medical advice, promotional claims, or dosing guidance.

Data Verification Notes: The sequence Ac-D-2-Nal-D-Phe(4-Cl)-D-3-Pal-Ser-Tyr-D-Har(Et2)-Leu-Har(Et2)-Pro-D-Ala-NH2 is confirmed by AbMole, ChemicalBook, and DailyMed. The free peptide molecular formula C80H113ClN18O13 and molecular weight 1570.34 are confirmed by AbMole, ChemicalBook, and the DailyMed prescribing information, which explicitly states that 1570.4 is the value as an anhydrous free base. The acetate salt molecular weight ambiguity is explicitly addressed: Selleck lists C80H113ClN18O13.2C2H4O2 with MW 1690.43 (diacetate), ChemicalBook reports 1690.42 for the diacetate, and TargetMol/Aobious list C82H117ClN18O15 with MW 1630.4 (monoacetate). The binding affinity data (Kd 0.4 nM, IC50 3.6 nM, pA2 9.3) are from BenchChem, Biorbyt, and Bertin Bioreagent and are assay-dependent. The histamine release EC50 of 11 microg/mL is from Bertin Bioreagent. The EMA statement on aqueous physiological pH solubility is from the European Medicines Agency assessment report. Solubility values are reported with their source conditions rather than reconciled into a single figure because the underlying measurements reflect different salt forms, dissolution techniques, and solvent systems. Storage guidance divergence, particularly the Biorbyt do not freeze instruction, is reported as-is rather than reconciled into a single blanket recommendation.

Formatting Note: All formulas, sequences, and comparison operators use plain ASCII notation to prevent character corruption on the platform. The micro symbol has been rendered as "microg" to avoid non-ASCII character risk. Section headings, table alignment, and spacing follow the approved product detail pattern. No trailing spaces or non-breaking characters are used; tables use consistent pipe alignment.