Reliable stability prediction to manage research or marketed vaccines and pharmaceutical products. "Avoid any doubt for the end-user of vaccine compliance at time of administration".

A major challenge for the pharmaceutical/vaccine industry is to anticipate and test/control product stability, regardless of the time/temperature profile of the product, from release to administration. Current empirical stability protocols performed to ensure product stability remain limited to the prediction of product stability in a thermal excursion (cold chain break) during their long-term storage. As recently recommended by the World Health Organization, mathematical models can be used for shelf-life and stability predictions. Therefore, various approaches have been published with good performance for simple chemical reactions. However, for biomolecules/vaccines, more complex reaction profiles require more complex models to predict their stability with a good level of confidence. This complexity constitutes a real scientific challenge because the number of model parameters increases with model complexity and need to be balanced with the limited number and quality of the available experimental data. We have developed a dedicated method/software based on different vaccines/pharmaceutical case studies. This predictive method considers phenomenological models, five levels of model confidence assessment, predictive quality value and simulated designs of experiment to improve and define the limits within which the prediction models can be used, and to increase model/prediction confidence to the required regulatory and scientific levels. This artificial intelligence system should help to avoid any doubt of stability at time of vaccine injection.

Construction of atomic models of full hepatitis B vaccine particles at different stages of maturation.

Hepatitis B, one of the world's most common liver infections, is caused by the Hepatitis B Virus (HBV). Via the infected cells, this virus generates non pathogen particles with similar surface structures as those found in the full virus. These particles are used in a recombinant form (HBsAg) to produce efficient vaccines. The atomic structure of the HBsAg particles is currently unsolved, and the only existing structural data for the full particle were obtained by electronic microscopy with a maximum resolution of 12 Å. As many vaccines, HBsAg is a complex bio-system. This complexity results from numerous sources of heterogeneity, and traditional bio-immuno-chemistry analytic tools are often limited in their ability to fully describe the molecular surface or the particle. For the Hepatitis B vaccine particle (HBsAg), no atomic data are available so far. In this study, we used the principal well-known elements of HBsAg structure to reconstitute and model the full HBsAg particle assembly at a molecular level (protein assembly, particle formation and maturation). Full HBsAg particle atomic models were built based on an exhaustive experimental data review, amino acid sequence analysis, iterative threading modeling, and molecular dynamic approaches.

Characterization of different strains of poliovirus and influenza virus by differential scanning calorimetry.

Vaccines against poliomyelitis and influenza contain inactivated forms of poliovirus and influenza virus. These antigens are generated on an industrial scale from the purified active viruses that have been analysed in this study by DSC (differential scanning calorimetry). Multiple unfolding transitions are seen for influenza virus A/New Caledonia/20/99 (H1N1), A/Panama/2007/99 (H3N2) and B/Shangdong/7/97. These data, combined with previously reported data on other influenza viruses, indicates that each influenza virus strain has a characteristic unfolding behaviour. Only minor changes were seen in the thermogram of betaPL (beta-propiolactone)-inactivated influenza virus, which is consistent with the proposition that betaPL reacts mainly with the nucleotide fraction of the virus. We demonstrate that a peak annotation of the thermogram of the native virus is possible using bromelain-treated virus and virosomes. At pH 1.5-2.5, poliovirus of type I unfolds in a single unfolding event with respective Tm (midpoint of protein unfolding transition) values between 34 and 45 degrees C. At pH 2, polioviruses of type II unfold equally in a single event, but, compared with the type I virus, with a Tm value increased by 3.7 degrees C. At neutral pH, the DSC thermogram of type I poliovirus was very 'noisy'. Data obtained offer the possibility of precisely characterizing and identifying different viral strains.