Precursor to metabolite: Ciclesonide to Des-ciclesonide

Ciclesonide is converted to Des-ciclesonide by airway esterase.

The pair

Ciclesonide — Prodrug ICS activated by esterases in the lung, limiting oral thrush.
Des-ciclesonide — Active ciclesonide metabolite formed by local esterases; supplies the glucocorticoid effect in airways and nasal tissue.