Quick Definition
What is Chemically Defined Medium (CDM)?: Chemically defined medium (CDM) is cell culture medium where every component is a purified, identified chemical entity with a known molecular structure and concentration. No undefined biological mixtures — such as serum, protein hydrolysates, yeast extract, or tissue extracts — are present. CDM provides maximum reproducibility and is the regulatory gold standard for GMP biopharmaceutical manufacturing.
Why chemically defined medium is the regulatory preference
Undefined raw materials (serum, hydrolysates) introduce variability that is difficult to control. Lot-to-lot FBS variation can shift cell growth rate, productivity, and product quality (glycosylation, charge variants) — requiring re-qualification when a new lot is introduced. CDM eliminates this variability because every component is defined and consistently supplied. This makes CDM the regulatory preference for all licensed biopharmaceutical manufacturing processes.
CDM for CHO and HEK293 production
The biopharmaceutical industry has largely transitioned to CDM for CHO-based mAb production. For HEK293-based AAV and lentiviral vector production, multiple CDM options are available. SeamlessBio supports CDM formulation by supplying rHSA and OsrhTF as ACF albumin and transferrin sources.
Key Facts
- Every component is chemically identified with CAS number, molecular formula, and defined concentration
- Excludes: FBS, human serum, hPL, protein hydrolysates, yeast extract, soy extract — all undefined biological mixtures
- Includes: amino acids, vitamins, inorganic salts, purified recombinant proteins (if fully characterised), synthetic lipids, glucose
- Recombinant proteins (rHSA, OsrhTF, recombinant insulin, recombinant growth factors) are chemically defined if fully characterised
- Used in: CHO cell culture for mAb production, HEK293 suspension for viral vectors, iPSC maintenance
- CDM requires lot-to-lot consistency — managed through CoA for every component and finished medium
Further Reading
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