Chemical structures of midazolam, remimazolam, and the carboxylic acid metabolite of remimazolam. Applying the same medicinal chemistry strategy that led to the discovery of remifentanil, our team at GlaxoSmithKline plc discovered the ultrashort-acting benzodiazepine, remimazolam. Remimazolam manifests similar pharmacologic properties as midazolam but with a predictable, ultrashort duration of action.