What is an achiral assay?

1 Answer
Aug 30, 2016

An achiral assay is a test to measure the properties of a drug without considering any differences between its enantiomers.

Explanation:

Most drugs are sold as mixtures of enantiomers in 50:50 ratios (racemic mixtures) or in other proportions.

You can do an achiral assay if:

  • The drug is enantiomerically pure
  • The drug is a mixture of enantiomers, but each has the same PD and PK properties

Other possibilities are:

1. The enantiomers exhibit different pharmacodynamic (PD) properties.

They may act differently on the body, such acting with different intensities and with different durations of effects.

2. The enantiomers have different pharmacokinetic (PK) properties.

The body may act differently on them, by absorbing them at different rates, carrying them to different tissues, transforming them into different metabolites, and excreting them at different rates.

3. The minor enantiomer may have the major activity.

If any of the above conditions exits, you should do a chiral assay, that is, you should evaluate the activity of each stereoisomer separately.