Triptorelin Pen
[D-Trp6]-GnRH at 2 mg/mL in bacteriostatic water, 6 mg in a 3 mL cartridge. Filled from a lot tested in the manufacturer’s own laboratory, with a certificate.
| Compound | Triptorelin [D-Trp6]-GnRH |
|---|---|
| CAS number | 57773-63-4 |
| Molecular formula | C64H82N18O13 |
| Theoretical mass | 1311.5 Da |
| Sequence / structure | pGlu-HWSY-[D-Trp]-LRPG-NH₂ (10 residues; N-terminal pyroglutamate; C-terminal amide) |
| Contents | Triptorelin: 6 mg per 3 mL pen (0.2% w/v) |
| Form | Sterile aqueous solution in bacteriostatic water (0.9% benzyl alcohol), supplied in a 3 mL glass cartridge inside a preloaded autoinjector pen fitted with a needle |
| Storage, sealed | Store at 2–8 °C in the original carton, protected from light |
| Format | Solution in a 3 mL pre-filled pen |
Sizes and lots
- 6 mg · 1 pen — $88.99
- 6 mg · Kit of 10 — $791.12
Triptorelin, or [D-Trp6]-GnRH, is the native GnRH decapeptide with D-tryptophan in place of glycine at position 6, a change that makes it a long-lived GnRH agonist. This listing is a preloaded pen with a 3 mL cartridge of triptorelin in bacteriostatic water at 0.2% w/v, 6 mg per pen. Published work on triptorelin covers the potency gained from that substitution, its resistance to enzymatic breakdown and how it degrades in aqueous solution.
What is in the pen
The 3 mL glass cartridge holds a sterile aqueous solution of triptorelin at 0.2% w/v, which is 2 mg/mL and 6 mg per pen, in bacteriostatic water with 0.9% benzyl alcohol as an antimicrobial preservative. The peptide is the same [D-Trp6]-GnRH sold dry in the triptorelin 2 mg vial. The safety data sheet classifies triptorelin as a reproductive toxicant in category 1B (H360), so the pen is stored locked up and handled with the precautions on the sheet; benzyl alcohol is listed as harmful if swallowed or inhaled, an eye irritant and a possible skin sensitizer.
Keep the pen at 2 to 8 °C in its carton, away from light, capped once in use and never frozen. A pen whose contents have frozen, changed color or turned cloudy should be discarded. How pens and vials compare as formats is covered in peptide pen vs vial.
What the research covers
Triptorelin descends from 1970s work on the glycine at position 6 of LH-RH. Coy and colleagues found that D-amino acids at that position gave analogues with far more gonadotropin-releasing activity than the natural hormone, and in immature male rats [D-Trp6]-LH-RH was 13 times as active over six hours1. The substitution also protects the peptide: Müller and colleagues described triptorelin as binding GnRH receptors with higher affinity and lasting longer in the circulation because it resists enzymatic degradation2.
For a product kept in solution, the stability studies are the more relevant part of the literature. In buffered aqueous solutions, triptorelin and native gonadorelin degraded in similar ways, were most stable near pH 5, and broke down faster in phosphate than in acetate buffer3. Those results describe purpose-made buffers, not bacteriostatic water with benzyl alcohol, so they do not give a shelf life for this pen, and the storage conditions on the safety data sheet apply. The full literature, from receptor pharmacology to the clinical record, is in the triptorelin guide.
Frequently asked questions
How is the pen different from the 2 mg vial?
The vial holds dry triptorelin kept at −20 °C until a study calls for it. The pen holds 6 mg already in solution at 2 mg/mL in bacteriostatic water and is kept at 2 to 8 °C. The vial leaves the concentration to the laboratory; the pen fixes it in advance.
How long does triptorelin keep once in solution?
The published stability work used buffered solutions near pH 5, not bacteriostatic water, so it gives no shelf life for this pen. Follow the safety data sheet: 2 to 8 °C, in the carton, away from light, never frozen, and discard the pen if the solution changes appearance.
References
- Coy DH, Vilchez-Martinez JA, Coy EJ, et al. Analogs of luteinizing hormone-releasing hormone with increased biological activity produced by D-amino acid substitutions in position 6. J Med Chem. 1976;19(3):423-5. DOI · PubMed
- Müller FO, Terblanchè J, Schall R, et al. Pharmacokinetics of triptorelin after intravenous bolus administration in healthy males and in males with renal or hepatic insufficiency. Br J Clin Pharmacol. 1997;44(4):335-41. DOI · PubMed
- Helm VJ, Müller BW. Stability of gonadorelin and triptorelin in aqueous solution. Pharm Res. 1990;7(12):1253-6. DOI · PubMed
For laboratory research use only. Not for human or veterinary consumption. Products have not been evaluated by the U.S. Food and Drug Administration and are not intended to diagnose, treat, cure or prevent any disease.