disomer

Disomer is a term used in pharmacology and medicine to refer to a specific stereoisomer of a chiral drug. Chiral drugs are molecules that exist in two non-superimposable mirror image forms, known as enantiomers. These enantiomers, despite having the same chemical formula and connectivity, can interact differently with biological systems, such as enzymes and receptors, due to their distinct three-dimensional structures.

Often, only one enantiomer of a chiral drug possesses the desired therapeutic effect, while the other enantiomer may be inactive, have different pharmacological effects, or even cause adverse reactions. The term "disomer" specifically denotes the enantiomer that is responsible for the intended biological activity or therapeutic benefit. For example, the drug ibuprofen is a racemate, meaning it is a 50:50 mixture of two enantiomers. The S-(+)-ibuprofen enantiomer is the pharmacologically active form responsible for its anti-inflammatory and analgesic properties.

The development and use of single enantiomer drugs, or "disomers," has become increasingly important in pharmaceutical research and practice. This is because administering a pure disomer can lead to improved efficacy, reduced side effects, and more predictable patient responses compared to using a racemic mixture. This approach is known as chiral switching or chiral drug development. Regulatory agencies like the FDA often encourage or require the development of single enantiomer drugs when significant differences in efficacy or safety exist between enantiomers.