How to Reconstitute CJC-1295 With DAC: Laboratory Reconstitution Guide
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How to Reconstitute CJC-1295 With DAC: Laboratory Reconstitution Guide
CJC-1295 with DAC (Drug Affinity Complex, MW 3647.3 g/mol, CAS 863288-34-0) is a synthetic GHRH analogue incorporating a maleimidoproprionic acid (MPA) modification at Lys30 that enables covalent albumin binding via thiol-maleimide conjugation, producing extended GHRH-R engagement in research models. It is supplied as a lyophilised white powder in a 10mL sterile glass vial containing 2mg of peptide. The DAC albumin-binding modification requires specific considerations during reconstitution and cell model assay design to ensure accurate pharmacology data.
Materials Required
- CJC-1295 with DAC 2mg lyophilised vial
- Bacteriostatic water (BAC water) — 10mL vial
- 1mL sterile syringe with needle
- Alcohol swabs (70% isopropyl)
- Nitrile gloves
- Permanent marker for labelling
- Refrigerator at 2–8°C for storage
Pre-Reconstitution Preparation
Inspect the vial for powder integrity and an intact seal. Allow the vial to equilibrate to room temperature for 15 minutes before reconstitution. CJC-1295 with DAC's MPA modification makes it slightly more hydrophobic than unmodified GHRH analogues — the room temperature equilibration step assists even dissolution by ensuring the solvent can uniformly wet the powder surface.
Step-by-Step Reconstitution Protocol
Step 1 — Prepare workspace. Wipe down the work surface with 70% isopropyl alcohol and allow to dry. Use nitrile gloves throughout.
Step 2 — Swab both stoppers. Clean the rubber stoppers of both vials with separate fresh alcohol swabs. Air dry for 10–15 seconds.
Step 3 — Draw 1mL of BAC water. Draw 1mL of bacteriostatic water into a sterile syringe. The 1mL volume yields a 2mg/mL stock that simplifies dilution for cell model assay preparation.
Step 4 — Inject slowly along the inner wall. Insert the needle into the CJC-1295 DAC vial and direct the BAC water stream slowly down the inner glass wall over 15–20 seconds. The DAC modification can make the peptide slightly more prone to surface adherence — slow, wall-directed injection minimises this.
Step 5 — Dissolve by gentle swirling. Gently swirl the vial for 30–60 seconds. CJC-1295 with DAC may take slightly longer to dissolve fully than the No DAC version due to its larger molecular weight and hydrophobic modification. Continue gentle swirling until the solution is fully clear. Do not shake or vortex.
Step 6 — Inspect and label. Confirm clarity of the solution. Label with reconstitution date, concentration, and initials.
Resulting Concentration
Adding 1mL BAC water to a 2mg CJC-1295 DAC vial yields a stock concentration of 2mg/mL (2000mcg/mL). For extended GHRH-R engagement studies in GH3 pituitary cell model preparations, working concentrations of 1nM–100nM are prepared by serial dilution into assay buffer or serum-free media.
Concentration Reference Table
| BAC Water Volume Added | Resulting Concentration |
|---|---|
| 1mL | 2.0mg/mL (2000mcg/mL) |
| 2mL | 1.0mg/mL (1000mcg/mL) |
Storage Conditions and Stability
Store lyophilised CJC-1295 DAC at −20°C prior to reconstitution. Once reconstituted, store at 2–8°C. Reconstituted solution is stable for up to 28 days under refrigeration. Do not freeze reconstituted solution. The MPA group is reactive toward free thiols — avoid storage in buffers containing DTT, beta-mercaptoethanol, or other thiol-containing reducing agents as these can modify the DAC functionality and alter albumin binding capacity.
Research Application Notes
The critical pharmacological distinction of CJC-1295 with DAC is its covalent albumin binding via the MPA reactive group, which produces sustained GHRH-R engagement by creating an albumin-bound peptide depot. In cell model assay design, this means the effective free concentration of CJC-1295 DAC in serum-containing media is substantially lower than nominal — similar to semaglutide's albumin binding consideration. For precise concentration-response pharmacology, use serum-free conditions or account for albumin binding using equilibrium dialysis data. In comparative studies with CJC-1295 No DAC, the DAC version produces sustained rather than pulsatile GHRH-R activation, providing mechanistically distinct receptor engagement data. CJC-1295 DAC 2mg vials are available from Pinnacle Peptides, verified at ≥99% purity by HPLC and mass spectrometry.
All content is intended for in vitro laboratory research purposes only. Not for human or animal consumption. Not intended to diagnose, treat, cure, or prevent any condition.
