Bioassay or Biological Assay
A bioassay or biological assay is a biological testing procedure for estimating the concentration of a pharmaceutical active substance in a formulated product or bulk material. In contrast to the common physical or chemical methods detailed information on the biological activity of a substance is achieved. Over the last decade biological assays (bioassays) have become more important to an effective quality control program in biopharmaceutical development and manufacturing.
The general approach of most bioassays (biological assays) is to perform a dilution assay, which measures the biological responses at several doses. A key assumption of a dilution assay is that the active component follows the same principle of activity in standard and sample preparation. In such case the unknown preparation may in theory be derived by diluting with inert components or by concentrating the bulk solution. This concept of similarity may be checked with the help of the parallel-line model (parallel-line assay) or with the help of parallel-logistics models.
Both methods are suitable for the analysis of the results obtained by several biological assays. An exemplary list of use is given below:
- Several immunochemical methods
- Microbiological assay of several antibiotics (diffusion method and turbidimetric method)
- Assay of human coagulation factor VIII
- Assay of diphteria vaccine
- Assay of heparin
- Assay of pertussis vaccine
- Assay of tetanus vaccine
- Assay of human anti-D immunoglobulin
- Assay for erythropoietin
