The Application of Capillary Electrophoresis for Vaccine Release and Characterization

Aug 01, 2009

What makes a vaccine? How are they different from therapeutic proteins?

A wide variety of antigens can be used as vaccine therapeutics. The first vaccines used the weakened live or killed microorganisms. As time progressed, protection could be acquired by using parts of a microorganism such as proteins or polysaccharides. A variety of technologies are used for preparing vaccines, including conjugation of polysaccharide or peptides to a carrier protein, recombinant expression and recombinant vectors. A protein vaccine (or the protein portion of a vaccine) is fundamentally the same as a protein therapeutic, from an analytical perspective.

Why Use CE for Vaccine Analysis?

The use of CE for vaccine analysis is increasing based on the number of articles being published and scientific talks being given. Interested readers are referred to a more comprehensive review of this topic (1).

CE is an established technique for the analysis of biotherapeutics (2–3) as its advantages (speed, reduced complexity of operation and improved reproducibility/automation) have supported the effective replacing of sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) analyses as well as isoelectric focusing (IEF) gels.

CE has been used to replace a variety of techniques for vaccine analysis. The traditional methods employed in vaccine analysis include colorimetric assays for concentration determination, SDS-PAGE and high performance liquid chromatography (HPLC) for purity and impurity analysis and IEF for isoelectric point (pI) determination. The methods suffer from many problems including precision (analyst-to-analyst and assay-to-assay issues being significant), poor resolution and limited accuracy and linearity. CE offers advantages in terms of cost, precision (many of the analyst-to-analyst and assay-to-assay variance components are minimized), linearity and ease-of-use. For the analyst, CE offers a greater degree of automation, less "babysitting" and easier method development/validation.

What are the issues associated with the use of CE for vaccine analysis?

In the early years, CE suffered from some precision issues, which limited its uptake. With the advent of modern instrumentation (for example, efficient temperature control) and methodologies (for example, use of migration time standards), many of the precision issues have disappeared. Vaccine analytical chemistry requires the combination of a variety of disciplines including molecular biology, biochemistry, immunology and virology along with traditional analytical chemistry. The seemingly slower acceptance of the technology in vaccines may have some origin in the diversity of the scientists working on vaccines.

Which Companies Are Using CE for Vaccine Analysis?

There are obvious problems of confidentially regarding pharmaceutical companies publishing their data so the reports understate the extent of usage. However, papers and presentations at scientific conferences show that the usage is widespread and includes vaccine manufacturers such as Sanofi-Aventis, Merck, and Wyeth.

Are Companies Routinely Using CE and Including CE Data in Regulatory Submissions?

Again there are obvious problems of confidentiality, regarding pharmaceutical companies publishing their data, so the exact details are unknown. However, it is know that biopharmaceutical companies are submitting CE methods, so it is reasonable to surmise the same is happening in vaccine submissions.

Is Standard CE Equipment Used for Vaccine Analysis?

Yes! The CE instrument used for vaccine analysis is identical to the CE instrument used for any other biopharmaceutical analysis. No special modifications are needed.