Albuterol enantiomers: pre-clinical and clinical value?

Front Biosci (Elite Ed). 2010 Jun 1;2:1081-92. doi: 10.2741/e166.

Abstract

Albuterol has been used in the acute treatment of asthma exacerbations for over 25 years. Its cost is low, and delivery can be tailored to allow dose-effect titration. Like other beta-2-adrenergic receptor agonists, it can exist as a racemate of two enantiomers, one active ((R)-albuterol), and one traditionally considered inert ((S)-albuterol). Basic investigations in airway cells and models from animals and humans have shown that (R)-albuterol, in both racemic and single enantiomer formulations, produces changes consistent with both relaxation of airway smooth muscle cells, and the reduction of inflammation. In contrast, (S)-albuterol typically has produces effects opposite to those of (R)-albuterol, i.e., antagonistic to the beneficial desired effects. Coupled with the fact that (S)-albuterol can persist 12 times longer than (R)-albuterol within the human circulation, findings suggest that paradoxical effects, sometimes seen with chronic racemic albuterol use, are due to (S)-albuterol. A number of clinical studies, to date, have been generally consistent with these findings; however, overwhelming evidence for clinical superiority of the (R)-albuterol single enantiomer over that within racemic albuterol remains to be obtained.

MeSH terms

  • Adrenergic beta-Agonists / chemistry
  • Adrenergic beta-Agonists / pharmacology
  • Adrenergic beta-Agonists / therapeutic use*
  • Albuterol / chemistry
  • Albuterol / pharmacology
  • Albuterol / therapeutic use*
  • Animals
  • Bronchodilator Agents / chemistry
  • Bronchodilator Agents / pharmacology
  • Bronchodilator Agents / therapeutic use*
  • Clinical Trials as Topic
  • Humans
  • Stereoisomerism

Substances

  • Adrenergic beta-Agonists
  • Bronchodilator Agents
  • Albuterol