Robustness testing of live attenuated rubella vaccine potency assay using fractional factorial design of experiments

Functional design of experiment for potency assay optimization and in-silico simulation

For biotherapeutic analytics, robust and reliable potency assays are required. Design of experiment (DoE) approaches are used to investigate the impact of multiple assay parameters. Currently, specific assay features (e.g., half effective concentration) are modelled independently from each other. A joint interpretation of several assay features is thus difficult. In our functional DoE approach, we use the functional relationship of the assay features to describe the sigmoidal dose-response curve. With the composed functional form, the direct impact of assay parameters on the dose-response curve shape was modelled. Moreover, a multivariate desirability was defined and used for assay optimization. We believe that functional modelling contributes to understanding the joint influence of assay parameters and helps to design robust biotherapeutic analytics.

Practical Considerations for Next-Generation Adjuvant Development and Translation

Over the last several years, there has been increased interest from academia and the pharmaceutical/biotech industry in the development of vaccine adjuvants for new and emerging vaccine modalities. Despite this, vaccine adjuvant development still has some of the longest timelines in the pharmaceutical space, from discovery to clinical approval. The reasons for this are manyfold and range from complexities in translation from animal to human models, concerns about safety or reactogenicity, to challenges in sourcing the necessary raw materials at scale. In this review, we will describe the current state of the art for many adjuvant technologies and how they should be approached or applied in the development of new vaccine products. We postulate that there are many factors to be considered and tools to be applied earlier on in the vaccine development pipeline to improve the likelihood of clinical success. These recommendations may require a modified approach to some of the common practices in new product development but would result in more accessible and practical adjuvant-containing products.

Stability of Minimum Essential Medium functionality despite L-glutamine decomposition

L-Glutamine (L-Gln) instability in liquid media is a well-known fact. Also, negative effect of ammonia, one of the L-Gln degradation products, on viability of many cell cultures and on replication of different viruses has been described. However, negative effects of ammonia have been reported in doses excessively exceeding those that could be generated in regularly used liquid culture media due to spontaneous L-Gln breakdown (below 2 mM). Traditional virus vaccine production processes have been established and registered involving L-Gln containing media use. Eventual culture media replacement in the regular production process belongs to the major regulative changes that require substantial financial expenses. The aim of this study was to evaluate the effect of storage of Minimum Essential Media with Hanks salts on their relevant biological functions during virus vaccine production process in relation to L-Gln decrease. Our results show a cell type dependent effect of spontaneous L-Gln degradation during medium storage. They also suggest that for cell cultures used in measles, mumps, and rubella virus production the media retain their functionality in respect to cell viability or virus growth over a certain time window despite L-Gln degradation.

Development, optimisation and validation of a stability-indicating HPLC method of achyrobichalcone quantification using experimental designs

INTRODUCTION

Achyrobichalcone is a new biflavonoid found in Achyrocline satureioides. It is structurally similar to other bioactive bichalcones that were proven to exert anti-cancer activity. Recently we isolated several achyrobichalcone batches on a semi-preparative scale, showing the need to assess the quality and stability of this substance by analytical methods.

OBJECTIVE

To develop and validate a stability-indicating HPLC method of achyrobichalcone quantification using experimental designs.

METHOD

The method was developed and optimised by Box-Behnken design using column temperature, flow rate and acetonitrile content in the mobile phase as factors and system suitability parameters as responses. Validation parameters were determined according to official compendiums. Robustness was determined by Plackett-Burman design. Stability of achyrobichalcone was assessed in alkaline, acid, oxidative, thermal and photolytic stress conditions.

RESULTS

The ideal chromatographic conditions were defined from the optimisation: 37 % of acetonitrile, flow rate of 1.2 mL/min and 33°C temperature. All factors were significant for the resolution between achyrobichalcone and impurities peaks and for the retention factor. The mathematical model developed exhibited a good predictive capacity, and the design proved suitable. The HPLC method was successfully validated, being linear, specific, accurate and precise. The robustness test revealed that the flow rate and detection wavelength should be strictly controlled, as they affect achyrobichalcone concentration. The analyte was unstable only in alkaline media.

CONCLUSION

The new method developed affords evaluation of the quality of achyrobichalcone obtained by isolation, and indicates the stability of the molecule under various stress conditions.