CJC-1295 — 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
- Mobile phase and gradient
- A: 0.1 % trifluoroacetic acid in water; B: acetonitrile. Gradient 20–50 % B over 35 min
- Detection
- UV 214 nm; 280 nm (Tyr1, Tyr10)
- Retention
- The DAC variant is more hydrophobic and retains longer; the two variants are readily resolved chromatographically, which means a laboratory that reports only a single unnamed peak has chosen not to make the distinction
§6.2Identity by mass spectrometry
Expected deconvoluted average mass 3647 Da (DAC) or 3368 Da (modified GRF(1-29)). These are separated by 279 Da — a difference no instrument in routine use could miss. The Institute therefore treats variant misidentification as a reporting failure rather than an analytical limitation.[3]
§6.3Related substances and degradation
Table 7. Related substances recorded for CJC-1295, with the process or storage route that generates each and its analytical signature.
| Related substance | Origin | Analytical signature |
|---|---|---|
| Wrong variant | The dominant finding | −279 Da or +279 Da relative to the labelled variant |
| Hydrolysed maleimide (DAC variant) | Storage in aqueous conditions | +18 Da; the hydrolysed maleamic acid cannot conjugate to albumin, so the compound loses its entire pharmacokinetic advantage while retaining almost the same mass and retention time. This is the most insidious quality failure for the DAC variant and requires deliberate method design to detect |
| Maleimide-thiol adducts | Reaction with free thiols during processing | Variable mass increase |
| C-terminal free acid | Incomplete amidation | +0.98 Da |
| Truncated chains | Incomplete coupling | Ladder pattern |
Degradation routes
- Maleimide hydrolysis is the critical route for the DAC variant and is rapid in aqueous solution at neutral pH
- Methionine-free sequence, so oxidation is a minor route
- Deamidation of Gln residues
- Loss of the C-terminal amide
§7Presentation, reconstitution and storage
§7.1Presentation and reconstitution
- Presentation
- Lyophilised powder in vial (research supply only)
- Reconstitution
- A 5 mg vial with 2.0 mL gives 2.5 mg/mL; a 100 µg quantity is then 0.04 mL, that is 4 units on a U-100 syringe — at the lower limit of reliable measurement, which argues for a larger reconstitution volume.
- Storage, lyophilised
- −20 °C, desiccated and protected from light
- Storage, reconstituted
- For the DAC variant, the Institute notes that maleimide hydrolysis proceeds in aqueous solution regardless of refrigeration, so reconstituted material loses conjugation capacity over days even when purity by reverse phase appears unchanged
- In-use period
- No supported in-use claim
This compound is the clearest case in the series where a conventional purity certificate can be entirely accurate and simultaneously uninformative: a hydrolysed-maleimide preparation may assay above 98 % pure and be pharmacologically inert.
§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.