Metalloporphyrins as cytochrome P450 models for chlorhexidine metabolite prediction

The catalytic oxidation of chlorhexidine (CHX, a strong microbicidal agent) mediated by ironporphyrins has been investigated by using hydrogen peroxide, mCPBA, tBuOOH, or NaOCl as oxidant. All of these oxygen donors yielded p-chloroaniline (pCA) as the main product. The higher pCA yields amounted to 71% in the following conditions: catalyst/oxidant/substrate molar ratio of 1:150:50, aqueous medium, FeTMPyP as catalyst. The medium pH also had a strong effect on the pCA yields; in physiological pH, formation of this product was specially favored in the presence of the catalysts, with yields 58% higher than those achieved in control reactions. This provided strong evidence that CHX is metabolized to pCA upon ingestion.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (68 K)Download as PowerPoint slideHighlights► Chlorhexidine (CHX) is prone to degradation in the presence of metalloporphyrins. ► p-Chloroaniline (pCA) is the main product from CHX catalytic degradation. ► The results show the strong possibility of pCA formation when CHX is ingested.