CJC-1295 DAC Purity: HPLC & MS Verification
CJC-1295 with Drug Affinity Complex (DAC) is a specialized growth hormone-releasing hormone (GHRH) analog engineered for extended half-life in preclinical models. Maintaining rigorous CJC-1295 DAC purity through high-performance liquid chromatography and mass spectrometry is critical for eliminating truncated impurities and ensuring reproducible receptor activation in laboratory settings.
Quick answer
CJC-1295 with Drug Affinity Complex (DAC) is a specialized growth hormone-releasing hormone (GHRH) analog engineered for extended half-life in preclinical models. Maintaining rigorous CJC-1295 DAC purity through high-performance liquid chromatography and mass spectrometry is critical for eliminating truncated impurities and ensuring reproducible receptor activation in laboratory settings.
Key takeaways
- [CJC-1295](/research-peptides/cjc-1295-no-dac) DAC is a synthetic 30-amino acid peptide analog of endogenous growth hormone-releasing hormone (GHRH).
- In quantitative molecular biology and endocrine research, peptide purity directly dictates the accuracy of bioassay data.
- High-performance liquid chromatography (HPLC) serves as the baseline quantitative method for assessing peptide purity.
- While RP-HPLC establishes chemical purity via relative peak area integration, High-Resolution Mass Spectrometry (HRMS) or Electrospray Ionization Mass Spectrometry (ESI-MS) is required to confirm structural identity and exact molecular weight.
Structural Mechanics of CJC-1295 DAC in Laboratory Research
CJC-1295 DAC is a synthetic 30-amino acid peptide analog of endogenous growth hormone-releasing hormone (GHRH). The primary sequence is modified at positions 2, 8, 15, and 27 to confer resistance against enzymatic cleavage by dipeptidyl peptidase-4 (DPP-4). The defining characteristic of this compound is the addition of a lysine residue at the C-terminus conjugated to a maleimidopropionic acid linker, collectively designated as the Drug Affinity Complex (DAC).
In cell culture and animal models, this bioconjugate linker selectively forms a covalent bond with circulating serum albumin via a nucleophilic addition reaction with the free thiol group at Cys34. This covalent albumin-binding mechanism substantially increases the functional half-life of the peptide from minutes to several days in preclinical species. Consequently, researchers utilizing CJC-1295 DAC can evaluate sustained GHRH receptor signaling without the high-frequency dosing schedules required by native GHRH or un-complexed peptides.
The Significance of >99% Purity in Preclinical Assay Integrity
In quantitative molecular biology and endocrine research, peptide purity directly dictates the accuracy of bioassay data. Impurities in synthetic peptides typically consist of truncated fragments, deleted amino acid sequences, oxidized methionine residues, and unreacted coupling reagents derived from solid-phase peptide synthesis (SPPS). When evaluating cjc-1295 dac purity, minor contaminants can alter binding kinetics at the pituitary GHRH receptor.
A purity profile below 98% introduces variable molar concentrations of active compound into experimental media or animal models, compromising dose-response curves. Furthermore, truncated sequences containing the reactive maleimide group may competitively bind to serum albumin without eliciting GHRH receptor activation, acting as antagonist-like artifacts. PX1 Research enforces a strict purity threshold (>99%) to ensure that all observed physiological changes—such as elevated growth hormone secretion and downstream IGF-1 expression—are entirely attributable to intact CJC-1295 DAC.
High-Performance Liquid Chromatography (HPLC) Analysis Metrics
High-performance liquid chromatography (HPLC) serves as the baseline quantitative method for assessing peptide purity. The separation of CJC-1295 DAC from its synthesis byproducts relies on reverse-phase HPLC (RP-HPLC) utilizing a C18 stationary phase column. Elution is performed using a binary gradient system composed of water with 0.1% trifluoroacetic acid (TFA) as Mobile Phase A and acetonitrile with 0.1% TFA as Mobile Phase B.
Due to the hydrophobic nature of the DAC moiety, precise temperature control (typically 40°C) and a carefully calibrated organic solvent gradient are required to resolve closely eluting deletion peptides. Ultraviolet (UV) detection is recorded at 214 nm, corresponding to the peptide backbone absorption wavelength, as well as 280 nm to monitor aromatic side chains. A compliant lot of CJC-1295 DAC displays a single, sharp primary peak accounting for >99% of the total integrated peak area, demonstrating the absence of structural isomer contaminants or uncoupled precursors.
Mass Spectrometry (MS) Sequence Verification and Deconvolution
While RP-HPLC establishes chemical purity via relative peak area integration, High-Resolution Mass Spectrometry (HRMS) or Electrospray Ionization Mass Spectrometry (ESI-MS) is required to confirm structural identity and exact molecular weight. The theoretical average molecular mass of CJC-1295 DAC (tetrasubstituted GHRH 1-29 with C-terminal Lys(DAC)-NH2) is precisely defined at 3647.28 Da.
During mass spectrometric analysis, the observed mass-to-charge ratios (m/z) are deconvoluted to determine the exact monoisotopic or average molecular weight of the synthesized lot. MS verification confirms that all four amino acid substitutions (D-Ala2, Gln8, Ala15, Leu27) and the C-terminal DAC group are present without mass deviations. This dual HPLC/MS analytical testing framework ensures that every batch dispatched by PX1 Research meets absolute structural standards before laboratory distribution.
Analytical Validation of the Maleimide (DAC) Functional Group
The unique chemical functionality of CJC-1295 DAC relies on the structural integrity of its terminal maleimide ring. During storage or under non-optimal synthesis conditions, the maleimide group can undergo ring-opening hydrolysis to form an inactive maleamic acid derivative, which completely abolishes its capacity to bind serum albumin.
To verify that the DAC feature remains functionally intact, specialized quality control assays—including spectrophotometric thiol-reactivity assays (such as Ellman’s reagent titrations) or targeted liquid chromatography-mass spectrometry (LC-MS) monitoring—are employed. Ensuring that the maleimide group has not undergone pre-experimental hydrolysis is a crucial component of CJC-1295 DAC quality assurance, guaranteeing that the molecule retains its extended biological persistence in preclinical models.
Endotoxin Quantification and Residual Counter-Ion Management
In vivo rodent models and primary cell cultures are exceptionally sensitive to bacterial endotoxins (lipopolysaccharides, LPS) and residual chemical counter-ions remaining from purification. Bacterial endotoxins induce systemic inflammatory responses, upregulate pro-inflammatory cytokines (such as TNF-alpha and IL-6), and obscure endocrine signaling metrics.
PX1 ResearchSubjects every lot of CJC-1295 DAC to rigorous bacterial endotoxin testing using Chromogenic Recombinant Factor C (rFC) or LAL assays, verifying endotoxin levels remain strictly below <0.01 EU/mg. Additionally, residual trifluoroacetic acid (TFA) salts utilized during RP-HPLC purification are systematically exchanged or quantified to prevent localized pH shifts and cell toxicity in downstream assays.
Comparative Analysis: GHRH Analogs and Secretagogue Class Metrics
When designing protocols for growth hormone axis research, investigators frequently evaluate multiple GHRH analogs and ghrelin receptor agonists to determine the optimal kinetic profile for their specific research model.
For instance, while CJC-1295 DAC provides sustained, non-pulsatile elevation of growth hormone and downstream IGF-1 levels over an extended timeframe, Modified GRF (1-29) (frequently termed CJC-1295 without DAC) lacks the albumin-binding moiety and exhibits a rapid clearance profile suitable for studying acute, pulsatile GH release. Similarly, early-generation GHRH analogs like Sermorelin possess a shorter biological half-life and require frequent administration in animal models to maintain receptor occupancy. When combined in dual-receptor activation studies alongside selective growth hormone secretagogues such as Ipamorelin, research teams must carefully account for the differing purity requirements, binding affinities, and clearance rates across each distinct peptide class.
Impact of Impurities on Pituitary Receptor Kinetics and Signal Transduction
The GHRH receptor is a Class B G-protein coupled receptor (GPCR) that signals primarily through the Gs alpha subunit, activating adenylate cyclase to increase intracellular cyclic AMP (cAMP) and stimulate growth hormone synthesis. In vitro studies demonstrate that deletion fragments lacking the N-terminal Tyr1 or D-Ala2 residues exhibit up to a 1000-fold reduction in receptor binding affinity.
If a research batch contains deletion sequences, these modified peptides can occupy GHRH receptor sites without inducing the conformational shift necessary for adenylate cyclase activation. This competitive antagonism skews affinity constant (Kd) and potency (EC50) calculations in pharmacological studies. Maintaining high CJC-1295 DAC purity eliminates receptor occlusion artifacts and ensures valid signal transduction measurements in pituitary cell cultures.
Reconstitution Standards and Laboratory Handling Protocols
To preserve the chemical stability and biological activity of high-purity CJC-1295 DAC, stringent reconstitution procedures must be maintained in the laboratory environment. The lyophilized peptide matrix should be allowed to equilibrate to room temperature inside a desiccator prior to reconstitution to prevent moisture condensation within the vial.
Reconstitution should be executed using sterile, bacteriostatic water or an appropriate low-pH buffered aqueous solvent (such as dilute acetic acid) if long-term solution storage is required. Vigorous vortexing must be avoided, as mechanical shear stress can disrupt secondary structure and promote peptide aggregation. Once reconstituted, solution aliquots should be stored at -20°C or -80°C to prevent peptide bond hydrolysis and maleimide ring degradation over time.
PX1 Research Quality Infrastructure and Lot Traceability
PX1 Research operates strictly within USA-synthesized, GMP-compliant production facilities. Analytical testing is conducted by independent ISO 17025 accredited laboratories to maintain absolute objectivity and precision in quality control reporting.
Every lot of CJC-1295 DAC is assigned a unique batch number linked to a downloadable Certificate of Analysis (COA) containing raw HPLC chromatograms, mass spectra, endotoxin assay results, and appearance logs. Research facilities ordering from PX1 benefit from same-day dispatch (Monday through Friday) from our CA and AZ distribution hubs, ensuring rapid transit and cold-chain integrity. Explore our complete technical library within the PX1 research library or apply for laboratory volume procurement via our wholesale research program.
Frequently Asked Questions
What is the targeted purity level for CJC-1295 DAC supplied by PX1 Research?
PX1 Research supplies CJC-1295 DAC at a guaranteed analytical purity of >99%, as determined by reverse-phase HPLC peak integration at 214 nm.
How does the DAC moiety alter the physical analytical profile compared to CJC-1295 without DAC?
The Drug Affinity Complex (DAC) adds a maleimidopropionic acid linker via a C-terminal lysine, increasing the molecular weight to 3647.28 Da and increasing hydrophobicity, which alters RP-HPLC retention time and requires specialized MS deconvolution.
What analytical techniques are included on the Certificate of Analysis (COA)?
Every lot-specific COA provides reverse-phase HPLC chromatograms for purity, ESI-MS or HRMS spectrum for molecular mass verification, chromogenic endotoxin assay results (<0.01 EU/mg), and mass solubility verification.
What are the specific endotoxin thresholds enforced for CJC-1295 DAC?
PX1 Research enforces a strict bacterial endotoxin limit of <0.01 EU/mg, verified via recombinant Factor C (rFC) or LAL assays to prevent inflammatory interference in cell assays and animal models.
How should CJC-1295 DAC be reconstituted for in vitro cell culture studies?
Lyophilized CJC-1295 DAC should be reconstituted using sterile bacteriostatic water or sterile buffered saline under a laminar flow hood, gently swirling without vortexing to avoid mechanical aggregation.
Why is maleimide ring stability critical during storage?
The maleimide group is responsible for covalent bioconjugation to serum albumin. Hydrolysis into maleamic acid renders the peptide incapable of albumin binding, neutralizing its extended half-life mechanism.
What storage conditions are recommended to prevent peptide degradation?
Lyophilized CJC-1295 DAC should be stored at -20°C or -80°C in a dry environment. Reconstituted solution aliquots must be kept frozen and protected from repeated freeze-thaw cycles.
How does CJC-1295 DAC compare to Modified GRF (1-29) in experimental design?
CJC-1295 DAC covalently binds serum albumin to maintain extended, baseline GHRH activation over several days, whereas Modified GRF (1-29) lacks the DAC linker, resulting in rapid clearance suitable for acute signaling studies.
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