Tesamorelin — analytical characterisation
Chromatographic conditions, identity, related substances, presentation, reconstitution and in-use stability.
§6Analytical characterisation
§6.1Chromatographic conditions
- Column
- C18, 4.6 × 250 mm, 5 µm; 300 Å wide-pore phase preferred for a 44-mer
- Mobile phase and gradient
- A: 0.1 % trifluoroacetic acid in water; B: acetonitrile. Gradient 25–50 % B over 40 min
- Detection
- UV 214 nm; 280 nm (Tyr1, Tyr10)
- Retention
- Late; the hexenoyl group adds hydrophobicity
§6.2Identity by mass spectrometry
[M+4H]⁴⁺ at m/z ≈ 1284.5, [M+5H]⁵⁺ at m/z ≈ 1028.2; deconvoluted average mass 5135.9 ± 3 Da. A 44-residue peptide requires careful deconvolution; nominal-mass agreement at low resolution is insufficient.[3]
§6.3Related substances and degradation
Table 7. Related substances recorded for Tesamorelin, with the process or storage route that generates each and its analytical signature.
| Related substance | Origin | Analytical signature |
|---|---|---|
| Des-hexenoyl (native GHRH 1-44) backbone | Failed or hydrolysed acylation | −96 Da; DPP-4-labile and pharmacologically inferior. This is the most consequential impurity for this compound and the one most often absent from supplier certificates |
| Met27 sulfoxide | Oxidation | +16 Da |
| Deamidated Asn8, Gln16, Gln29, Gln34 forms | Storage | +1 Da each; a 44-mer with four deamidation-prone residues shows a complex late-storage profile |
| Truncated chains | Incomplete coupling in a long synthesis | Multiple species; a 44-residue solid-phase synthesis has substantially lower crude purity than a 30-mer, so a high final purity claim implies a demanding purification |
| Trifluoroacetate | Counter-ion | This sequence contains six arginine and five lysine residues and binds counter-ion strongly; TFA content above 10 % by mass is possible in poorly desalted material |
Degradation routes
- Methionine oxidation
- Deamidation at multiple sites
- Hydrolysis of the N-terminal hexenoyl amide, regenerating DPP-4-labile native GHRH
- Aggregation of a long, highly charged peptide at concentration
§7Presentation, reconstitution and storage
§7.1Presentation and reconstitution
- Presentation
- Lyophilised powder for reconstitution (approved product supplied with sterile water)
- Reconstitution
- A 2 mg vial reconstituted with 0.5 mL gives 4 mg/mL; the approved 1.4 mg dose is then 0.35 mL, that is 35 units on a U-100 syringe. Research vials are commonly 5 mg or 10 mg; a 10 mg vial with 2.0 mL gives 5 mg/mL and a 1 mg dose of 0.20 mL, that is 20 units.
- Storage, lyophilised
- The 2 mg presentation is stored at 2–8 °C; some presentations are stored below 25 °C. Research material should be held at −20 °C
- Storage, reconstituted
- Use immediately after reconstitution for the approved product; the label does not support storage of the reconstituted solution
- In-use period
- The approved label directs immediate use after reconstitution. The Institute publishes no extended in-use claim, and notes that the manufacturer’s own conservatism here is informative.
Because the acylation is the entire basis of the compound’s pharmacokinetic advantage, an analytical certificate that does not distinguish acylated from non-acylated material has not confirmed identity in any meaningful sense.
§7.2In-use stability
Applicable standards: CEI-MS-01 · CEI-MS-02 · CEI-MS-03 · CEI-MS-04 · CEI-MS-05 · CEI-MS-06. The full series is at methodological standards.
Working calculators: reconstitution and insulin-unit conversion · purity against peptide content · certificate minimum-data checker.
References cited on this page
References are numbered in order of first citation in this document. Each superscript in the text links to its entry below.
- United States Pharmacopeial Convention. General Chapter ⟨1225⟩ Validation of Compendial Procedures. United States Pharmacopeia — National Formulary (USP–NF) 2024;USP 2024 Issue 1. identifier not held by the Institute
- International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use. ICH Q2(R2) Validation of Analytical Procedures. ICH Harmonised Guideline 2023;Step 4 version, 1 November 2023. identifier not held by the Institute
- International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use. ICH Q6B Specifications: Test Procedures and Acceptance Criteria for Biotechnological/Biological Products. ICH Harmonised Tripartite Guideline 1999;Step 4 version. identifier not held by the Institute
- International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use. ICH Q1A(R2) Stability Testing of New Drug Substances and Products. ICH Harmonised Tripartite Guideline 2003;Step 4 version. identifier not held by the Institute
- Manning MC, Chou DK, Murphy BM, Payne RW, Katayama DS. Stability of protein pharmaceuticals: an update. Pharmaceutical Research 2010;27(4):544–575. doi:10.1007/s11095-009-0045-6 · PMID 20143256
Identifiers are reproduced only where the Institute holds them. Where a digital object identifier or PubMed identifier is not shown, the Institute has recorded the journal and year and has not constructed an identifier.