Keeping chirality under control

About two-thirds of drug molecules are chiral; their chirality can influence the drug’s properties and efficiency in the body. In some cases only one enantiomer is biologically active and in others, such as thalidomide, one is harmful. Increasingly, drugs are sold as pure enantiomers. But even when only one enantiomer is prepared, racemisation can still happen.

L-Tyrosine is a non-essential amino-acid with a similar structure to L-dopa, which is used in Parkinson’s disease treatment.

Exposing L-tyrosine to sunlight, heat and UV light causes it to partially racemise. After it is incorporated into LDHs’ layers, racemisation is prevented. Duan’s group suggests that this is because the guest L-tyrosine molecules are restricted within the layers of the LDH host. Also, the LDH stops UV light reaching the molecules.

Duan plans to continue investigating the interactions between biomolecules and LDHs, and sees possibilities for other applications, saying ’intercalation in the layered host has another potential benefit.LDHs are effective as a matrix for controlled release drug delivery systems’.

Rebecca Lavender