| Target Molecule | Cetrorelix Acetate |
| Synonyms | Cetrorelix, Cetrotide, SB-075, NS-75A, [Ac-D-Nal1, D-Cpa2, D-Pal3, D-Cit6, D-Ala10]-GnRH |
| CAS Number | 130143-01-0 (diacetate salt); 120287-85-6 (free base) |
| Sequence (3-Letter) | Ac-D-Nal(2)-D-Phe(4-Cl)-D-Pal(3)-Ser-Tyr-D-Cit-Leu-Arg-Pro-D-Ala-NH₂ |
| Sequence (1-Letter) | Ac-[D-2Nal]-[D-4ClPhe]-[D-3Pal]-S-Y-[D-Cit]-L-R-P-[D-Ala]-NH₂ |
| Molecular Formula | C₇₀H₉₂ClN₁₇O₁₄ (anhydrous free base) |
| Molecular Weight | 1431.06 (anhydrous free base) |
| Service Category | Custom Peptide Synthesis / CDMO Manufacturing |
| Synthesis Purity | Customizable (e.g., ≥95%, ≥98% via HPLC) |
| Appearance | White to off-white lyophilized powder |
| Counter Ion | Diacetate (standard pharmaceutical salt), TFA, or custom salt options |
| Synthesis Technology | Solid-Phase Peptide Synthesis (SPPS) for Multiple Unnatural and D-Amino Acids |
| Modification Options | D-amino acid incorporation, unnatural side-chain substitution (D-Cit, D-Nal, D-Pal, D-Cpa), N-terminal acetylation, stable isotope labeling (13C, 15N), diastereomer impurity standards |
| Available Scale | Milligram (R&D) to Kilogram (Commercial CDMO) |
| Analytical Data | Comprehensive COA, HPLC, MS, and chiral purity confirmation provided per batch |
| Usage | Raw material synthesized strictly for laboratory research, analytical development, and industrial formulation. Not a finished medicine. |
Cetrorelix Acetate (CAS 130143-01-0) is a synthetic decapeptide functioning as a potent GnRH receptor antagonist. Its sequence features extensive non-standard modifications, including five unnatural D-amino acids: D-Nal(2), D-Phe(4-Cl), D-Pal(3), D-Cit, and D-Ala, alongside N-terminal acetylation. We target this sequence to supply high-purity reference materials and raw materials for reproductive endocrinology and oncology research.
Incorporating consecutive bulky D-enantiomers and unnatural building blocks creates severe steric hindrance during solid-phase peptide synthesis (SPPS), raising the risk of incomplete couplings and epimerization. Our peptide synthesis platform utilizes specialized coupling cocktails, elevated-temperature protocols, and real-time monitoring to ensure high-fidelity assembly without chiral inversion.
Yes. We provide specialized peptide modification services for GnRH antagonists. Capabilities include the deliberate synthesis of diastereomers and deletion sequences as critical impurity reference standards, site-specific stable isotope labeling (13C, 15N) for quantitative LC-MS/MS bioanalysis, and fluorescent or biotin tagging.
Our manufacturing infrastructure scales production from milligram-level analytical batches to multigram and kilogram commercial quantities. We optimize preparative HPLC purification and controlled counter-ion exchange (ensuring diacetate salt conversion) to guarantee strict batch-to-batch consistency.
We operate as an integrated technical partner providing complete peptide CDMO solutions. Our team manages sequence optimization, impurity profiling, analytical method validation, and regulatory documentation to support complex drug development pipelines.
Cetrorelix Acetate (CAS 130143-01-0), commercialized under the brand name Cetrotide, is a synthetic decapeptide operating as a competitive gonadotropin-releasing hormone (GnRH) receptor antagonist. Defined by the heavily modified sequence Ac-[D-2Nal]-[D-4ClPhe]-[D-3Pal]-S-Y-[D-Cit]-L-R-P-[D-Ala]-NH2, it incorporates five distinct D-enantiomers, N-terminal acetylation, and C-terminal amidation. Synpeptide delivers comprehensive custom synthesis solutions for this target molecule, demonstrating advanced technical expertise in non-standard amino acid assembly, stereochemical control, and CDMO manufacturing.
The assembly of Cetrorelix presents substantial synthetic obstacles. Incorporating multiple bulky non-canonical residues—specifically D-Nal(2), D-Phe(4-Cl), D-Pal(3), and D-Cit—generates severe steric hindrance, leading to incomplete coupling cycles and on-resin aggregation. Our custom peptide synthesis platform resolves these hurdles using optimized Solid-Phase Peptide Synthesis (SPPS) protocols on low-loading amide resins. By utilizing targeted activating reagents, temperature control, and rigorous capping cycles, we suppress deletion fragments and epimerization, delivering raw materials with rigorous purity specifications (typically ≥95% or ≥98% via HPLC).
Due to multiple chiral centers and unnatural residues, Cetrorelix demands comprehensive analytical validation. Diastereomeric impurities arising from partial racemization can compromise biological activity. Through our peptide modification services, we synthesize deliberate diastereomeric variants and deletion sequences as reference standards for stability-indicating assays. We also offer site-specific stable isotope labeling (13C, 15N) for pharmacokinetic mass spectrometry and fluorescently tagged analogues for receptor-binding studies.
Moving a heavily modified decapeptide from exploratory R&D to multi-gram or commercial volume demands robust downstream process engineering. The unique hydrophobic and basic properties of the non-standard residues require customized chromatographic isolation. We execute large-scale peptide synthesis for Cetrorelix by optimizing preparative HPLC purification and controlled lyophilization. Our infrastructure accommodates demands from milligram batches to kilogram commercial lots, ensuring consistent counter-ion exchange (providing the pharmaceutical diacetate salt form) across all production volumes.
We deliver comprehensive technical support as a fully integrated peptide CDMO. Our development specialists assist pharmaceutical partners with process optimization, stability testing, impurity identification, and analytical method validation. Every batch is released with complete analytical documentation—including COA, HPLC purity traces, and exact mass confirmation—ensuring regulatory alignment for downstream therapeutic programs.
