Description

Carfilzomib Impurity 4 (n-Oxide Impurity) is a structurally defined degradation product and critical reference standard used in the analytical monitoring of carfilzomib, a proteasome inhibitor employed in oncology therapeutics. This impurity is essential for ensuring drug substance purity, stability, and regulatory compliance throughout pharmaceutical development and manufacturing. It is primarily utilized by quality control laboratories, contract research organizations (CROs), and active pharmaceutical ingredient (API) manufacturers engaged in method validation, forced degradation studies, and impurity profiling of carfilzomib-based formulations.

Application

• Reference standard for HPLC and UPLC method development and validation in carfilzomib quality control
• Forced degradation study material to identify and quantify n-oxide formation pathways under oxidative stress conditions
• Calibration standard in quantitative impurity testing per ICH Q3B(R2) guidelines
• Stability-indicating assay support for shelf-life determination of carfilzomib drug products
• Raw material qualification and batch release testing in GMP-compliant API manufacturing
• Proficiency testing and inter-laboratory comparison programs for oncology-related small-molecule APIs
• Supporting regulatory submissions (FDA, EMA, PMDA) requiring comprehensive impurity characterization data
• Research applications in structure–activity relationship (SAR) studies of proteasome inhibitors

Basic Information

Product Name	Carfilzomib Impurity 4 (n-Oxide Impurity)
CAS No.	1672698-96-2
Molecular Formula	C44H59N7O7
Molecular Weight	797.99 g/mol
Synonyms	Carfilzomib N-oxide; Carfilzomib n-Oxide Impurity; (2S)-N-[(1S)-1-({(2S)-2-[(tert-Butoxycarbonyl)amino]-4-methylpentanoyl}amino)-3-methylbutyl]-2-({(2R,3R)-3-[(2-morpholinoethoxy)carbonyl]oxiran-2-yl}methyl)pentanamide N-oxide; N-Oxide derivative of carfilzomib; Carfilzomib impurity F; CFZ-N-oxide; Carfilzomib related compound 4 (n-oxide); (2S)-N-[(1S)-1-{[(2S)-2-(tert-Butoxycarbonylamino)-4-methylpentanoyl]amino}-3-methylbutyl]-2-{[(2R,3R)-3-(2-morpholinoethoxycarbonyl)oxiran-2-yl]methyl}pentanamide N-oxide
EINECS	Contact for details

Quality Control

Our products undergo rigorous quality testing to ensure compliance with industry standards. Certificates of Analysis (COA) are available upon request. All batches are tested per ICH Q5A(R2) and Q5B guidelines for biological and biotechnological products where applicable, and conform to current Good Manufacturing Practice (cGMP) requirements for reference standards. Testing includes identity confirmation (IR, HPLC retention time match), assay (HPLC area normalization), and impurity profiling (HPLC with PDA detection). Reference standards are qualified per USP General Chapter <1225> on Validation of Compendial Procedures.

Storage

Preserve in a tightly closed container, protected from light. Store at 2–8 °C under inert atmosphere (nitrogen or argon) to prevent further oxidation. Due to its hygroscopic nature, maintain in a low-humidity environment (<30% RH) and minimize exposure to ambient air during handling.

Specification

Item	Specification
Appearance	White to off-white solid
Identification (IR)	Conforms to reference standard
Identification (HPLC)	Retention time matches reference standard (±0.2 min)
Assay (HPLC)	98.0–102.0%
Related Substances (HPLC)	Single impurity ≤0.5%; Total impurities ≤1.0%
Residual Solvents (GC)	Meets ICH Q3C limits
Water (Karl Fischer)	≤0.5%
Heavy Metals	≤10 ppm

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.