BioPharmaSpec scientists have been characterizing heavily N and O-glycosylated proteins for over three decades and can work with you to devise the best structural and physicochemical characterization strategies for your development plans.
Whether the product of interest is a new product or a biosimilar (e.g. Erythropoietin or Darbepoetin), structural and physico-chemical characterization are a crucial part of biopharmaceutical product development. The expectations of the EMA and US FDA, in terms of structural characterization, are outlined in ICH Topic Q6B.
ICH Topic Q6B provides examples of technical approaches which might be considered for structural characterization and confirmation, and evaluation of physicochemical properties of the desired product, drug substance and/or drug product. The guideline recognizes that new analytical technology and modifications to existing technology are continuously being developed and should be utilized when appropriate.
Regulatory guideline documents recommend that the following are assessed:
- Primary (de novo) Amino Acid Sequence
- Amino Acid Composition
- Terminal Amino Acid Sequence
- Peptide Map
- Disulfide Bridges
- Carbohydrate Structure
- Secondary and Tertiary Structure
Specific Technical Considerations
Particular attention should be paid to the analysis of glycosylation when analyzing heavily glycosylated proteins. As requested in the ICH guidelines (Topic Q6B), the carbohydrate content (neutral sugars, amino sugars and sialic acids) should be determined. In addition, the structure of the carbohydrate chains, the oligosaccharide pattern (antennary profile), the glycosylation site(s) and occupancy should be analyzed.
Glycan structures should be characterized both in terms of size and relative abundance to the extent possible, and particular attention should be paid to their degree of sialylation, the glycans present at each of the sites (glycosylation site analysis) and the degree of glycosylation at each site (glycosylation site occupancy).
BioPharmaSpec has also developed methods for identifying immunogenic epitopes such as Galalpha1-3Gal antennae.