Triptorelin Technical Specification Sheet
Molecular Properties
| Parameter |
Value |
| Chemical Name |
Triptorelin Acetate / [D-Trp⁶]-LHRH |
| Amino Acid Sequence |
pGlu-His-Trp-Ser-Tyr-D-Trp-Leu-Arg-Pro-Gly-NH₂ |
| Molecular Formula |
C₆₄H₈₂N₁₈O₁₃ |
| Molecular Weight |
1311.47 g/mol (free base); 1431.55 g/mol (acetate salt) |
| CAS Number |
57773-63-4 (free base); 140194-24-7 (acetate) |
| Sequence Length |
10 amino acids (synthetic GnRH superagonist) |
| Receptor Target |
GnRH receptor (GnRHR) on pituitary gonadotrophs |
Physical Properties
| Property |
Specification |
| Appearance |
White to off-white lyophilized powder |
| Solubility |
Freely soluble in water, PBS, or 0.9% saline at ≥2 mg/mL; pH 4.0-6.5 |
| pH (1% solution) |
5.0 - 6.5 |
| Hygroscopicity |
Moderate; desiccated storage required |
| Solution Stability |
Stable at 4°C for 14-21 days (improved vs native GnRH) |
Analytical Specifications
| Test |
Specification |
| HPLC Purity |
≥98.0% |
| Mass Spectrometry |
Confirmed [M+H]⁺ = 1311.47 ± 0.5 Da (free base) |
| Peptide Content |
≥95% (by amino acid analysis) |
| Endotoxin Level |
<1.0 EU/mg |
| Acetate Content |
8-12% (for acetate salt form) |
| TFA Content |
≤0.1% |
| Water Content |
≤6% (Karl Fischer) |
Storage Parameters
| Condition |
Specification |
| Lyophilized Storage |
-20°C to -80°C, desiccated, protected from light |
| Lyophilized Shelf Life |
36 months when stored properly |
| Reconstituted Storage |
2-8°C for up to 21 days; -20°C for up to 6 months |
| Reconstitution Protocol |
Add 1.0 mL sterile water or bacteriostatic water to 1 mg vial; gentle vortex 30-60 seconds |
| Freeze-Thaw Cycles |
Tolerates up to 5 cycles; stability superior to native GnRH |
| Light Sensitivity |
Minimal; standard amber vials recommended |
Research Dosing Reference
| Application |
Typical Dose Range |
Frequency |
Route |
| In Vitro Pituitary Cell Assays |
0.1-10 nM (50-200x more potent than GnRH) |
Acute or chronic exposure |
Culture media |
| Small Animal Models (Rodent) |
50-500 μg/kg |
Single dose or weekly depot |
SC injection |
| Receptor Desensitization Studies |
100-200 μg/kg |
Single dose; monitor 7-21 days |
SC or IM |
| Gonadal Suppression Models |
0.5-2 mg/kg (depot formulation) |
Monthly or every 3 months |
IM depot injection |
Note: Dosing information is for research reference only. Triptorelin is intended for research purposes. Initial stimulation followed by downregulation occurs with chronic administration.
Key Research Studies
| Year |
Study Focus |
Key Findings |
| 1982 |
Superagonist potency characterization |
D-Trp⁶ substitution increased GnRHR binding affinity 50-100 fold vs native GnRH; demonstrated EC₅₀ of 0.01-0.05 nM for LH release from rat pituitary cells |
| 1995 |
Pharmacokinetics and receptor dynamics |
Single SC dose (100 μg/kg) produced initial LH surge at 4h followed by sustained suppression for 14-28 days; receptor downregulation detected by day 7 with >80% reduction in GnRHR density |
| 2004 |
Depot formulation development |
Biodegradable microsphere depot released triptorelin over 1-3 months; maintained therapeutic suppression with single injection; plasma levels 0.5-2 ng/mL sustained gonadal axis suppression |
| 2012 |
Structure-activity and metabolic stability |
D-amino acid at position 6 conferred peptidase resistance; plasma half-life extended to 3-5 hours vs 2-4 minutes for native GnRH; metabolic stability increased 50-100 fold |
Mechanism of Action
| Biological Pathway |
Description |
| Receptor Binding |
High-affinity GnRHR agonist; Kd ~0.1-0.5 nM (50-100x higher affinity than native GnRH) |
| Initial Agonist Effect |
First 2-7 days: supraphysiological GnRHR activation → LH/FSH surge → transient increase in sex steroids |
| Receptor Downregulation |
Continuous GnRHR stimulation → receptor internalization and degradation → 70-90% reduction in receptor density by day 14 |
| Gonadal Suppression |
Sustained receptor desensitization → loss of LH/FSH pulsatile secretion → hypogonadal state (castration levels) |
| Half-Life |
3-5 hours (SC); depot formulations provide sustained release over weeks to months |
Comparative Analysis: Triptorelin vs Native GnRH
| Parameter |
Native GnRH (Gonadorelin) |
Triptorelin |
| Position 6 Amino Acid |
Gly (L-amino acid) |
D-Trp (D-amino acid) |
| Receptor Affinity (Kd) |
1-5 nM |
0.1-0.5 nM (50-100x higher) |
| Half-Life (SC) |
2-4 minutes |
3-5 hours (75-150x longer) |
| Potency (LH release EC₅₀) |
0.5-2 nM |
0.01-0.05 nM (50-200x more potent) |
| Clinical Effect |
Pulsatile stimulation |
Biphasic: initial surge then suppression |
| Dosing Frequency |
Pulsatile (hourly) required |
Daily to monthly (depot) |
Quality Control Parameters
| Test Method |
Acceptance Criteria |
| Appearance (visual) |
White to off-white powder; no discoloration |
| Chiral Purity (D-Trp⁶) |
D-isomer ≥99%; L-isomer <1% at position 6 |
| RP-HPLC (purity) |
Main peak ≥98.0%; no single impurity >0.5% |
| ESI-MS (identity) |
[M+H]⁺ = 1311.47 ± 0.5 Da confirmed |
| Biological Activity |
≥90% potency vs reference standard in LH release assay |
Disclaimer: This product is intended for research use only. Not for human or veterinary diagnostic or therapeutic use. Triptorelin causes initial hormonal flare followed by suppression.