BioPharmaSpec is a contract research organisation (CRO) focusing on the structural analysis of proteins, glycoproteins, peptides, and oligonucleotides and their conjugations. The company emerged from the M-Scan group, founded by Professor Howard Morris who developed the cornerstone mass spectrometry techniques for the structural characterisation of large molecules. They have labs in the UK, US, and Europe, and fulfil all of the requirements from ICH Q6B for full structural characterisation.
Synthetic peptides are peptides which are manufactured using chemical rather than biological means. Larger biological molecules can’t be produced in this way, but for shorter molecules like peptides, their chemical synthesis allows creativity and experimentation in their design.
For example, modifications like the stereoisomers or acylation can be incorporated where they may have been off-limits via recombinant production. These modifications can confer beneficial properties such as an increase in half-life, protease resistance, or biological activity.
Both the EMA and FDA have established regulatory guidelines for the analysis and characterization of synthetic peptides. These define their expectations and highlight the importance of understanding their structural attributes and impurity profiles.
Those expectations include product characterisation at the primary, secondary and tertiary structure, confirmation of the amino acid sequence, and the assessment of disulfide bridges. Furthermore, orthogonal techniques should be used to give the greatest strength to the analytical data. Both product and process related impurities are risks of chemical manufacture, which also need to be considered.
Mass spectrometry techniques can be used to provide a large amount of this structural information about the product. Intact mass, impurity profile, amino acid sequencing, and disulfide bridges, can all be assessed using mass spectrometry. Furthermore, peptide fragment ions can be generated in real time. The presentation goes on to explain common fragmentation pathways in mass spectrometry, such as the production of b and y ions, which help in determining the peptide sequence.
Impurities in synthetic peptides can arise from the synthesis process, and mass spectrometry is crucial for identifying these impurities, which can include stereoisomers and truncated species. Easton highlighted the need to differentiate between L and D forms of amino acids using techniques like GC-MS and LC-MS to ensure the purity of synthetic peptides.
The presentation concluded with an explanation of the LC-MRM method, a quadrupole technique that enhances the sensitivity and specificity of amino acid detection in synthetic peptides.
