Standard Operating Procedure to Optimize Resazurin-Based Viability Assays.

The resazurin assay, also known as the Alamar Blue assay, stands as a cornerstone technique in cell biology, microbiology, and drug development. It assesses the viability of cells through the conversion of resazurin into highly fluorescent resorufin. The resulting fluorescence intensity provides a reliable estimate of viable cell numbers. Cytotoxicity assays, such as the resazurin-based method, play a crucial role in the screening of potential drug candidates and in the assessment of pharmaceutical and chemical toxicity. In recent years, inconsistencies have arisen in pharmacogenomic studies, often due to poorly optimized laboratory protocols. These inconsistencies hinder progress in understanding how substances affect cell health, leading to unreliable findings. Thus, the need for standardized and rigorously optimized protocols is evident to ensure consistent and accurate results in cytotoxicity studies. This manuscript describes a standardized procedure for optimizing resazurin-based viability assays to improve the reliability of cytotoxicity data. This optimization approach focuses on critical experimental parameters and data quality, aiming to achieve a level of measurement imprecision of less than 20%. In conclusion, to address the critical issues of reproducibility and reliability, protocol standardization, such as the one described in this manuscript, can greatly enhance the credibility of cytotoxicity studies, ultimately advancing drug safety assessments.

Quantification of cells with specific phenotypes I: determination of CD4+ cell count per microliter in reconstituted lyophilized human PBMC prelabeled with anti-CD4 FITC antibody.

A surface-labeled lyophilized lymphocyte (sLL) preparation has been developed using human peripheral blood mononuclear cells prelabeled with a fluorescein isothiocyanate conjugated anti-CD4 monoclonal antibody. The sLL preparation is intended to be used as a reference material for CD4+ cell counting including the development of higher order reference measurement procedures and has been evaluated in the pilot study CCQM-P102. This study was conducted across 16 laboratories from eight countries to assess the ability of participants to quantify the CD4+ cell count of this reference material and to document cross-laboratory variability plus associated measurement uncertainties. Twelve different flow cytometer platforms were evaluated using a standard protocol that included calibration beads used to obtain quantitative measurements of CD4+ T cell counts. There was good overall cross-platform and counting method agreement with a grand mean of the laboratory calculated means of (301.7 ± 4.9) µL(-1) CD4+ cells. Excluding outliers, greater than 90% of participant data agreed within ±15%. A major contribution to variation of sLL CD4+ cell counts was tube to tube variation of the calibration beads, amounting to an uncertainty of 3.6%. Variation due to preparative steps equated to an uncertainty of 2.6%. There was no reduction in variability when data files were centrally reanalyzed. Remaining variation was attributed to instrument specific differences. CD4+ cell counts obtained in CCQM-P102 are in excellent agreement and show the robustness of both the measurements and the data analysis and hence the suitability of sLL as a reference material for interlaboratory comparisons and external quality assessment.

The Year's New Drugs & Biologics - 2009.

This annual article presents new drugs and biologics that were launched or approved for the first time during the previous year. In 2009, 51 new medicines and vaccines reached their first markets. Line extensions (new indications, new formulations and new combinations of previously marketed products) accounted for more than 30% of the new products launched in 2009. In addition to providing an overview of all drugs and biologics launched or approved for the first time ever in the previous year, this article will also review in further depth the first-in-class drugs launched for the first time last year, providing a better understanding of their novel mechanisms of action; an analysis of the discovery and development periods for the year's new products; and a comprehensive overview of drug repositioning as a strategy for extending the life spans of medicines. We also provide a brief glimpse at selected drugs and biologics which could reach their first markets in the foreseeable future.

Overcoming the obstacles in the pharma/biotech industry: 2009 update.

The research-based biopharmaceutical industry faced new challenges during 2009, many rooted in the global economic recession, which further complicated a situation that was already characterized by the obstacles traditionally debated in this and other publications: generic competition, patent expirations and accusations of declining innovation. Once again, companies have been forced to seek out new strategies (mergers, acquisitions, licensing deals, offshore clinical testing and more) in order to cut costs and fill the gaps in their R&D pipelines. However, it is conceivable that the existing R&D model has limitations that can no longer be overcome via these traditional strategies and that the time has come for an entirely new model.

The year's new drugs & biologics - 2008.

This annual article presents new drugs and biologics that were launched or approved for the first time during the previous year. In 2008, 31 new medicines-this figure includes both drugs and biologics for therapeutic use as well as new diagnostic agents-reached their first markets. Line extensions (new indications, new formulations and new combinations of previously marketed products) accounted for more than one-third of the new medicines launched in 2008. In addition to providing an overview of all drugs and biologics launched or approved for the first time ever in the previous year, this article will also review in further depth the first-in-class drugs launched for the first time last year, providing a better understanding of their novel mechanisms of action; an analysis of the discovery and development periods for the year's new products; and a comprehensive overview of drug repositioning as a strategy for extending the life spans of medicines. We also provide a brief glimpse at selected drugs and biologics which could reach their first markets in the foreseeable future.

Overcoming the obstacles in the pharma/biotech industry: 2008 update.

In the face of patent expirations on blockbuster drugs and declining innovation in the industry, pharma/biotech companies are restructuring their research and development operations and are pursuing an aggressive strategy of acquisitions, licensing deals and research collaborations in an attempt to fill the gaps in their product pipelines.