Biosimilars/Biologics Drug Characterisation

Accredited Structural and Functional Characterisation

Delivering immediate, independent and affordable assistance in demonstrating biosimilarity, with data packs to meet FDA and ICH guidelines (ICH Q6B).

Biosimilar development begins with extensive structural and functional characterisation which underpins all further product development activities. Proteomics International operates a world leading ISO/IEC 17025:2005 accredited protein analysis laboratory, with a proven track record in characterising biosimilars.

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ISO 17025 is the most widely used standard for USA Federal testing laboratories and shares the same objective as Good Laboratory Practice (GLP) to assure data quality.

The FDA states that the submission of a laboratory package from an ISO 17025 accredited facility will likely provide sufficient information for the purposes of their review.

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Projects successfully undertaken include:

  • Insulin/Insulin lispro/Insulin glargine
  • Epidermal growth factor (EGF)
  • Rituximab (Zytux)/MabThera
  • Ustekinumab (Stelara)
  • Trastuzumab (Herceptin)
  • Omalizumab
  • Adalimumab
  • Icatibant acetate
  • Human growth hormone (HGH)
  • Granulocyte-colony stimulating factor (G-CSF)
  • Human follicle stimulating hormone (h-FSH)
  • Recombinant coagulation factor VII
  • Immunoglobulin (IgG) Fab fragment & whole molecule
  • Eptifibatide (cyclic peptide)
  • Lactoferrin
  • Protamine Sulfate
  • Semaglutide


Services include:

Project specific quotations will be provided upon request.
Request Form: Biosimilars | Biologics


Mass Spectrometry (MS) Analysis of Intact Proteins and Peptides

Suitable for pure samples, this service provides a molecular mass for the protein or peptide of interest.

Samples are processed intact (no enzyme digestion) using  LC/MS.

Request Form: Protein Mass Analysis


Disulphide Bridge Analysis

This technique is used to characterise disulphide folding pattern, ie an analysis of which Cys residues are linked.

Scope of work:

  • Confirmation of protein by MS. Unambiguous identification is provided using our standard MS/MS sequencing service.
  • Identification of location of disulphide bonds. Full protein characterisation will be performed using our high-end ESI-MS instruments. The analysis will look for disulphide bonded peptide fragments following enzyme digestion of the protein.

For analysis we require the full theoretical protein sequence, and postulated S-S bridging patterns.

Request Form: Disulphide Bridge Analysis


Peptide Mapping Analysis

A standard technique to confirm the amino acid sequence of a molecule, Peptide Mapping Analysis uses multiple enzyme digest strategy to break apart a protein into smaller peptide fragments which are subsequently analysed on the mass spectrometer.

Peptide fragments digested with different enzymes will highly likely provide overlapping amino acid sequence data, allowing for the accurate determination and confirmation of the amino acid sequence of the full length of a target protein molecule.

An added value of Peptide Mapping Analysis is that modifications such as C-terminal truncations and/or N-terminal modifications may also be detected.

For more information please email


N- & C-Terminal Analysis

Using mass spectrometry, we are able to determine a protein’s amino acid sequence at the N-terminus. Mass spectrometry can also be used to identify the amino acid sequence of N-terminally blocked proteins, where traditional N-terminal Edman sequencing fails.

Using our heavy water labeling strategy, we can determine the amino acids at a protein’s C-terminus. Using the correct enzyme during protein digestion in heavy water, we are able to confirm the protein’s C-terminus and any truncated forms.

For more information please email



Comprehensive glycoprotein characterisation at the monosaccharride level is now available to complement existing detailed mapping of the amino acid sequence. Glycosylation analysis is ideal for Quality Control of Biosimilars, recombinant/fusion proteins and antibodies, and is a key component of the ICH Q6B guidelines for molecular characterisation.

For more information please email


Weak Cation Exchange Analysis

PTM modification can affect protein function. Impurities of proteins due to formation of charged PTM(s) can be compared using a specialised chromatographic technique called weak cation exchange analysis. This UV-HPLC based technique separates the proteins and their impurities by taking advantage of their different charge states and provides relative quantification of the impurities.


Special Services:

Disulphide bridge analysis – 2-tag technology

Typical disulphide bond analysis only provides confirmation of the existence of theoretical disulphides that are known to exist in the antibody. PI’s patented 2-tag technology can provide relative quantification of disulphide bonded (oxidised) cysteines vs. non-disulphide bonded (reduced) cysteines. This method provides more precise information on efficiency of manufacturing process with respect to the tertiary structure of antibodies.


Iso-Aspartate quantification analysis

Iso-Aspartate is often an unwanted PTM that can occur in proteins. Iso-Aspartic acid residues can result from gradual non-enzymatic deamidation of asparagine or rearrangement of aspartic acid residues during storage or handling. This can affect the specificity and binding of antibody to antigen and for proteins may affect their enzymic activity. Using the power of a unique quantitative kit and UV-HPLC, Iso-Aspartate levels can be quantitated based on the amount of protein provided by PI’s new isoquant assay methodology.


N-terminal pyroglutamination relative quantitation analysis

Pyroglutamination of the N-terminal of heavy chain in antibodies often occurs as a result of manufacturing and handling process. This can be relatively quantified with PI’s new mass spectrometry-based technique.


C-terminal lysine truncated peptide quantification analysis

C-terminals of heavy chain in antibodies often have a variable modification of lysine truncation as an artefact of manufacturing. This C-terminal lysine truncation can be quantified using PI’s new mass spectrometry-based C-terminal analysis method.


For more information please email


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