A high-throughput screening approach can be followed for evaluating the performance of excipients against aggregation of a protein antigen at air-liquid interface.

For a long time, beer staling has been a prime concern in brewery research. Yet, to improve flavor stability, better knowledge of all chemicals involved is still needed. From our aroma extract dilu-tion analyses (AEDA) applied to naturally aged lager beers emerged an old-beer-like odorant at RICP-SIL 5 CB = 1532 and RIFFAP = 2809, with a FD value close to that of trans-2-nonenal (the well-known cardboard off-flavor found in aged beers). Specific phenol extraction, GC cold trapping, and mass spectrometry (electron impact and chemical ionization) enabled us to identify it as 4-vinylsyringol. Although already mentioned in some fresh beers, this compound had never been highlighted as involved in the aging process of lager beers.

In high-throughput screening (HTS) assays, the use of ultraviolet absorption spectroscopy (UA) is commonly limited to concentration and turbidity measurements. Our aim was to evaluate microplate-based UA and its second-derivative [(2d)UA] for measuring the conformational stability of two recombinant antigenic proteins in the presence of 44 excipients. Protein conformational stability was assessed by (2d)UA upon titration with guanidine hydrochloride. (2d)UA was compared with tryptophan fluorescence spectroscopy (TF) and differential scanning fluorimetry (DSF), both commonly used techniques for measuring protein conformational stability. The HTS data were corrected for plate, row and column effects by applying a median polish procedure. Irrespective of the unfolding method applied, similar stabilizing excipients were identified by all analytical methods for a given antigen. The native forms of both antigens were destabilized by arginine, hydroxypropyl-β-cyclodextrin, and sodium docusate, and were protected by polyols. The median polish correction improved the quality of the prediction models and the screening resolution. The higher sensitivities of TF and DSF compared with (2d)UA allowed the identification of a larger number of stabilizing excipients. However, similar screening resolutions (z'-factor > 0.8) were observed for 2dUA, TF, and DSF in a HTS of excipients applied to one of the antigens. Therefore, (2d)UA deserves more attention in HTS studies focused on protein conformational stability.

Background/Aims: Ensuring verum and placebo cannot be visually distinguished from each other is a critical aspect of blinded controlled clinical trials. Our objective was to propose a rational approach to the visual evaluation of placebo matching candidates. Methods: Verum and placebo samples were prepared in clear clinical ancillary supplies (intravenous bags, syringes and administration lines) covered at different levels using opaque sleeves. Triangle and tetrad tests, two sensory discriminative testing methods widely used in the food industry, were applied to assess visual differences between verum and placebo. Results: Triangle and tetrad test results allowed defining the level of opaque coverage required to ensure blinding for three biological drug molecules of therapeutic interest. While the limited number of panelists did not allow a statistically sound comparison of triangle and tetrad test methodologies, tetrad test has a theoretical higher power than triangle test, meaning fewer panelists are needed to reach the same statistical conclusion. Conclusion: Tetrad test offers a rational approach to define a blinding strategy for ancillary supplies used in a controlled clinical trial.

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