Protein characterization is a broad term describing the profile or fingerprint of a large molecule’s (or biologic’s) physical, chemical, and biological properties. Characterization of the protein will test the purity, activity, and the quantity of the protein. Methods for quantification include chromatography methods such as high-performance liquid chromatography (HPLC) or antibody dependent methods such as Enzyme-linked immunosorbent assay (ELISA). As more and more large molecule drugs are developed the need for protein characterization, specifically the dosing solution of the drug can be streamlined.
Traditionally dose solution testing for large molecules have been performed by a GMP analytical lab. Perhaps the reason for the lack of dose solution testing by GLP bioanalytical labs stems from when large molecules exploded on to the scene in the 2000’s. GLP labs would try to adapt cell based potency assays designed for release testing into cell based neutralizing antibody methods. This approach does not work well and in recent years has been abandoned. As the drug development field continues to evolve KCAS sees a new opportunity to adopt protein characterization methods into a bioanalytical method.
Typically the reagents used for ELISA based dose solution testing of proteins, specifically the capture and detection antibodies, are the same as used for the PK assay. If the plan is to take the GMP analytical method and try and adapt it to a GLP bioanalytical method this will fail just like the cell based potency assay testing. Why? The GMP lab, during the development and validation of the dose solution method, is not designing the method to support GLP regulated PK analysis. Dose solution testing methods are buffer based so they do not test for matrix effects nor a minimum required dilution. Additionally, the standards and controls are not designed to support PK sample analysis regulations.
Recently a client came to KCAS because they needed a laboratory to transfer and validate their dose solution testing method and requested the method be adopted to support PK analysis. It came as no surprise that during the transfer we determined the method developed for dose solution testing was not adequate for support of PK sample testing. We at KCAS, using the building blocks of the dose solution method, developed an Electrochemiluminescence (ECL) PK method, which met the regulatory guidelines for PK analysis.
If we had developed a single ECL method and validated it for dose solution testing and for PK analysis, we could have saved our client an estimated $20,000 – $25,000 in development and validation costs and an estimated 1-2 months of time. We at KCAS are now offering method development and validation of dose solution testing of large molecules in addition to our PK and ADA services. Perhaps we can help you with your protein characterization dose solution needs and save you time and money.