Pre-Clinical Testing → Example of In Vitro Study to Assess Drug Toxicity

An example of in vitro study to assess drug toxicity – MTT cell viability assay

The MTT cell viability assay is used to measure cellular metabolic activity as an indicator of cell viability, proliferation and cytotoxicity. This colorimetric assay is based on the reduction of a yellow coloured salt to a purpose coloured salt by viable, metabolically active cells. The colour can be quantified by a multi-well spectrophotometer. The absorbance of cells treated by a pre-clinical drug candidate are normalized to that of control cells, and the data is presented as % viability. In the given example above, a drug at 50 µM concentration reduces the cell viability by approximately 75%, while no statically significant reduction in cell viability is observed at 12.5 µM. Practically, this set of data means when the drug is used at 50 µM, it will lead to cell death, and 12.5 µM is non-toxic concentration to cells.